International Journal of Gynecological Pathology

High-grade Pelvic Serous Carcinoma Within the Fallopian Tube Lumen: Real or Artifact?

Tumor cells are occasionally observed in the lumen in histologic sections of the fallopian tube from women with gynecologic cancer. There is some evidence that this finding may be important in endometrial cancer, but its significance is unknown in women with extrauterine pelvic serous carcinomas (tubo-ovarian high-grade serous carcinoma). Fallopian tube sections from 213 women with extrauterine pelvic serous carcinoma were reviewed, and luminal tumor cells were correlated with clinical and pathologic features. Intraluminal tumor cells were found in 84 patients (39%). The presence or absence of luminal tumor cells correlated significantly with serous tubal intraepithelial carcinoma (52% and 33%, respectively, P=0.004), tubal lymphatic invasion (32% and 12%, respectively, P=0.0002), and number of tube sections reviewed (6.6 and 4.9 for lumen-positive and lumen-negative cases, respectively, P=0.0056). There was no correlation with the presence of ascites, peritoneal cytopathologic findings, lymph node metastases, or FIGO stage. In the setting of pelvic serous carcinoma, a substantial portion of fallopian tube tissue is often distorted, fibrotic, and difficult to identify. Since the identification of luminal tumor cells, serous tubal intraepithelial carcinoma and tubal lymphatic invasion all depend on identification of fallopian tube tissue, these correlates with luminal tumor cells could be a result of a higher likelihood of their observation when tubal tissue can be more readily identified and may not necessarily reflect a biologically important phenomenon. It remains unclear whether and in what proportion this finding reflects an artifact of specimen handling.

Comparison of Frozen and Permanent Section Diagnosis in Ovarian Neoplasms: Analysis of Factors Affecting Accuracy

Ovarian cancer is the seventh most common form of cancer among women worldwide. The aim of the study was to determine the accuracy of a frozen section and the factors affecting the accuracy of frozen diagnosis of ovarian neoplasms. This retrospective, cross-sectional study was conducted on 401 patients with ovarian masses with frozen section diagnosis in Shahid Faghihi Hospital affiliated to Shiraz University of Medical Sciences between 2014 and 2018. Each ovarian tumor sample was evaluated for histopathologic diagnosis using frozen and paraffin-embedded sections, which were reviewed by an expert gynecologic pathologist. Accuracy and diagnostic values were estimated by comparing the results of the 2 techniques, using the paraffin section as the gold standard. The overall accuracy of the frozen section was 94.5%. Its sensitivity was 85.3% for malignant, 88.2% for borderline, and 99.6% for benign tumors. Its specificity was also 99.7% for malignant, 98.0% for borderline, and 90.9% for benign tumors. The positive predictive value was 98.9% for malignant, 86.5% for borderline, and 94.6% for benign tumors. Most false negatives occurred in mucinous and borderline tumors. The sensitivity of malignant tumors of germ cell and sex cord-stromal cell types were 64.3% and 95.5%, respectively. The specificity of germ cell and sex-cord stromal tumors were 100% and 93.8%, respectively. Frozen section seems to be a precise technique for histopathologic diagnosis of ovarian tumors. However, borderline and mucinous tumors are the most problematic issues during frozen section diagnosis and malignant germ cell tumors have the lowest sensitivity.

Prospective Clinical Prognostication of Endometrial Carcinomas Based on Next-Generation Sequencing and Immunohistochemistry—Real-World Implementation and Results at a Tertiary Care Center

Based on findings from The Cancer Genome Atlas and the Proactive Molecular Risk Classifier for Endometrial Cancer algorithm, endometrial carcinoma can now be stratified into 4 prognostically distinct subgroups based on molecular alterations and immunohistochemical (IHC) aberrations. In this study, we describe the de novo adoption and clinical reporting of prognostic subgroup classification based on next-generation sequencing (NGS) and IHC analyses of all endometrial carcinoma resections at a single institution, framed by the Exploration, Preparation, Implementation, and Sustainment model. Results from the first 13 months show 188 tumors underwent analysis by a combination of IHC and a medium-sized (56 analyzed genes) NGS-based assay. All cases were assigned as either POLE (POLE-mutated) (5.3%), mismatch repair deficient (27.7%), no specific molecular profile (45.7%), or p53 abnormal (21.3%) inclusive of multiple-classifier cases. NGS-based analysis revealed additional distinctions among the subgroups, including reduced levels of PI3K pathway activation in the p53 abnormal subgroup, an increased rate of CTNNB1 activating mutation in the no specific molecular profile subgroup, and lower TP53 mutation variant allele frequencies in POLE and mismatch repair deficient subgroups compared with the p53 abnormal subgroup. Overall, we describe the testing protocol, reporting, and results of a combination of NGS and IHC to prospectively prognosticate endometrial carcinomas at a single tertiary care center.

Characteristics and Significance of Tertiary Lymphoid Structures Based on Molecular Subtypes in Endometrial Cancer

The purpose of this study is to investigate the characteristics and significance of tertiary lymphoid structures (TLSs) in endometrial cancer (EC) based on molecular subtypes. A total of 220 patients with EC were retrospectively enrolled, including 20 with polymerase epsilon ultramutated (POLE-mut), 63 with mismatch repair deficient, 32 with p53 abnormal, and 105 with no specific molecular profile. The presence and maturity of TLSs were determined by immunohistochemical markers (CD3, CD20, CD21, and Bcl6). Disease-free survival served as the endpoint event. TLSs were found in 91 out of 220 patients (41.1%), with 68 located in peritumoral tissues and 37 exhibiting well-formed germinal center structures. The presence and different maturity of TLSs were closely associated with tumor-infiltrating lymphocytes and the programmed cell death ligand-1 expression. Moreover, TLSs displayed heterogeneity across different molecular subtypes. Notably, the TLSs, tumor-infiltrating lymphocytes, and expression of the programmed cell death ligand-1 were significantly enriched in POLE-mut EC. Multivariate logistic regression analysis showed the presence of TLSs (odds ratio: 3.483, 95% CI: 1.044–11.623, P = 0.042) as a potential predictor of POLE-mut EC. Kaplan-Meier survival curves revealed that molecular subtypes significantly stratified prognosis in patients with EC (P = 0.002), whereas TLSs did not. Multivariate Cox regression analysis indicated that The International Federation of Gynecology and Obstetrics stage and Ki-67 expression were independent prognostic factors affecting disease-free survival in patients with EC, and TLSs were not included. In conclusion, TLSs in EC exhibit heterogeneity based on molecular subtypes, necessitating further exploration to determine their clinical application value.

Corded and Hyalinized Endometrioid Adenocarcinoma (CHEC) of the Uterine Corpus are Characterized by CTNNB1 Mutations and Can Show Adverse Clinical Outcomes

Corded and hyalinized endometrioid adenocarcinoma (CHEC) is a morphologic variant of endometrioid adenocarcinoma that is typically low-grade [International Federation of Gynecology and Obstetrics (FIGO) grade 1–2]. CHEC exhibits a biphasic appearance with gland forming adenocarcinoma merging with a diffuse component with corded growth often in a hyalinized matrix; squamous differentiation is frequent and osteoid production can be seen. This morphologic appearance can invoke a large differential diagnosis including carcinosarcoma. CHEC is thought to be associated with good clinical outcome although the available data is sparse. We performed detailed clinical, morphologic, immunohistochemical, and molecular analyses on a cohort of 7 CHEC. Six cases exhibited features of classic low-grade CHEC while one case showed greater cytologic atypia (high-grade CHEC). Patient age ranged from 19 to 69 yr. Four patients presented at stage I, 2 at stage II, and 1 at stage III. All tumors demonstrated nuclear staining for beta-catenin and loss of E-cadherin in the corded and hyalinized component. There was relative loss of epithelial markers. Loss of PTEN and ARID1A was seen in 4 and 3 tumors, respectively, and 1 tumor displayed loss of MLH1 and PMS2. Next-generation sequencing revealed CTNNB1 and PI3K pathway mutations in all 7 cases with TP53 and RB1 alterations in the high-grade CHEC. Clinical follow-up was available for 6 patients; 2 died of disease (48 and 50 mo), 2 are alive with disease (both recurred at 13 mo), and 2 have no evidence of disease (13 and 77 mo). Our study shows that CHEC universally harbors CTNNB1 mutations with nuclear staining for beta-catenin, can rarely show high-grade cytology, and can be associated with adverse clinical outcomes.

Nuclear Beta-Catenin Expression in Endometrioid Intraepithelial Neoplasia (Atypical Hyperplasia) Does Not Predict Carcinoma on Subsequent Hysterectomy

Beta-catenin (BC) mutations are associated with a high risk of recurrence in otherwise low-grade, early-stage uterine endometrioid adenocarcinomas. Recent literature suggests nuclear BC expression by immunohistochemistry is highly sensitive and specific for BC mutations. The significance of BC expression in endometrioid intraepithelial neoplasia (EIN/atypical hyperplasia) and its relationship to altered differentiation patterns in EIN has yet to be fully explored. Cases meeting current diagnostic criteria for EIN based on H&E examination were obtained from 2 institutions (years 1999–2014). Patterns of altered differentiation (eg, tubal, squamous morular metaplasia, mucinous, secretory) were noted. Representative blocks were stained for BC, and expression patterns recorded. Follow-up and demographic data was obtained from the electronic medical record. Ninety-six cases were included (84 biopsies, 12 hysterectomies). BC nuclear expression was identified in 41 cases (42.7%), with 33 of 41 demonstrating foci of nonmorular BC staining. BC staining in any component of EIN was not significantly associated with the presence of carcinoma on subsequent hysterectomy (P=0.79). When restricting to nonmorular BC, the results were the same (P=0.56). Cases with tubal differentiation were significantly less likely to demonstrate nonmorular BC than cases with no specific pattern of differentiation (P<0.01). EIN frequently demonstrates BC nuclear positivity, especially in cases without tubal differentiation. BC nuclear expression in EIN does not appear to be associated with an increased likelihood of carcinoma on subsequent hysterectomy. Our results do not support routine use of BC immunohistochemistry as a prognostic biomarker in cases of EIN.

Does Specimen Type Have an Impact on HER2 Status in Endometrial Serous Carcinoma? Discordant HER2 Status of Paired Endometrial Biopsy and Hysterectomy Specimens in the Presence of Frequent Intratumoral Heterogeneity

A recent clinical trial showed prolonged progression-free survival in human epidermal growth factor receptor 2 (HER2)-positive advanced stage and recurrent endometrial serous carcinomas when trastuzumab was added to traditional chemotherapy. Approximately one third of these tumors are HER2-positive and have been described to show unique characteristics of HER2 protein expression and gene amplification, including significant intratumoral heterogeneity, in recent studies. However, currently, there are no standard protocols for the selection of optimal specimen type or algorithm for HER2 testing in endometrial serous carcinomas. The current study aimed to evaluate the concordance of HER2 status between endometrial biopsy/curettage and subsequent hysterectomy specimens in endometrial serous carcinoma. A total of 57 patients with endometrial serous carcinoma with available HER2 status were identified during the study period, 14 of which (14/57, 25%) were HER2-positive by immunohistochemistry and/or fluorescent in situ hybridization (FISH). The final study cohort consisted of 40 paired endometrial biopsies/curettings and hysterectomies to include all 14 HER2-positive tumors and 26 selected HER2-negative tumors to represent an equal distribution of HER2 immunohistochemical scores. HER2 FISH was performed on all tumors with an immunohistochemical score of 2+. HER2 immunohistochemical scores, heterogeneity of HER2 expression, FISH results, and the overall HER2 status were compared between the 2 specimen types. HER2 status was successfully assigned in both specimen types in 37 cases, as three specimens showed inadequate FISH signals. Concordant HER2 status was observed in 84% of cases (31/37), with identical HER2 immunohistochemical scores in 65% (26/40) of tumors. Among the 6 tumors with a discordant HER2 status, 2 were HER2 negative in the biopsy and positive in the hysterectomy, and 4 were HER2-positive in the biopsy and negative in the hysterectomy. The false-negative rate would be 15.4% and 26.7% if only the biopsy or only the hysterectomy would be the basis for the result, respectively. Intratumoral heterogeneity of HER2 protein expression was present in 22 tumors (55%), including all cases with a discordant HER2 status. The concordance rate of HER2 status between paired endometrial biopsies/curettings and hysterectomies of endometrial serous carcinoma is lower than the reported rates of breast cancer, and comparable to those of gastric carcinomas. Frequent heterogeneity of HER2 protein expression combined with the possibility of a spatially more heterogenous sampling of endometrial cavity in biopsies and curettings, and the potential differences in specimen handling/fixation between the 2 specimen types may explain our findings. HER2 testing of multiple specimens may help identify a greater proportion of patients eligible for targeted trastuzumab therapy and should be taken into account in future efforts of developing endometrial cancer-specific HER2 testing algorithm.

Interlaboratory Concordance of ProMisE Molecular Classification of Endometrial Carcinoma Based on Endometrial Biopsy Specimens

Molecular classifiers improve the consistency of categorization of endometrial carcinoma and provide valuable prognostic information. We aimed to evaluate the interlaboratory agreement in ProMisE assignment across 3 dedicated Canadian gynecologic oncology centers. Fifty cases of endometrial carcinoma diagnosed on biopsy were collected from 3 centers and 3 unstained sections were provided to each participating site so that immunohistochemistry for MSH6, PMS2, and p53 could be performed and interpreted at each center, blinded to the original diagnoses and the results from other centers. A core was taken for DNA extraction and POLE mutation testing. Overall accuracy and κ statistic were assessed. MSH6, PMS2, and p53 could be assessed for all 50 cases, with agreement for 140/150 results. There was a high level of agreement in molecular classification (κ=0.82), overall. Cases with a discordant result for one of the features used in classification (n=10) were reviewed independently and the most common reason for disagreement was attributable to the weak p53 staining in 1 laboratory (n=4). Interpretive error in PMS2 (n=1) and MSH6 (n=2) assessment accounted for 3 of the remaining disagreements. Interpretive error in the assessment of p53 was identified in 2 cases, with very faint p53 nuclear reactivity being misinterpreted as wild-type staining. These results show strong interlaboratory agreement and the potential for greater agreement if technical and interpretive factors are addressed. Several solutions could improve concordance: central quality control to ensure technical consistency in immunohistochemical staining, education to decrease interpretation errors, and the use of secondary molecular testing.

Primary Angiosarcoma of the Cervix: Case Report of a Rare Lesion

Angiosarcomas of the female genital tract are rare and primary angiosarcoma of the cervix is extremely rare with only one prior case report. We report a case of a primary cervical angiosarcoma in a 43-yr-old woman who presented with heavy vaginal bleeding. Cervical biopsy and subsequent radical hysterectomy showed a malignant vascular tumor which was composed of spindled and epithelioid cells and formed abortive vascular channels. Immunohistochemically, the tumor cells were diffusely positive for CD31, CD34, ERG, and cyclin D1 and focally positive for D2-40. A reverse transcription polymerase chain reaction test for YWHAE-NUTM2 genetic fusion was negative excluding a YWHAE-translocated high-grade endometrial stromal sarcoma. The tumor formed a 5 cm mass within the cervix with microscopic involvement of the endometrium, superficial myometrium, and vagina. Metastatic microscopic tumor deposits were present in both ovaries, left fallopian tube, one paracervical lymph node, and one pelvic lymph node. In reporting this unusual case we discuss the differential diagnosis.

LAG-3 and GAL-3 in Endometrial Carcinoma: Emerging Candidates for Immunotherapy

LAG-3 is an immunosuppressive checkpoint molecule expressed on T cells. One of its ligands, GAL-3, can promote the progression of malignancy and has been identified on tumor cells. Both LAG-3 and GAL-3 are the targets of emerging immunotherapies, but have not been well-studied in endometrial carcinomas. LAG-3, CD3, and GAL-3 immunohistochemistry was performed on 75 endometrial cancers (25 nonmethylated mismatch repair-deficient, 25 MLH1-hypermethylated mismatch repair-deficient, and 25 mismatch repair-intact). LAG-3+ and CD3+ lymphocytes were averaged per high-power field. Tumoral GAL-3 expression was semiquantitatively scored. Tumor-infiltrating lymphocyte expression of LAG-3 and CD3 were positively correlated (Spearman ρ=0.521, P<0.001) and greater in mismatch repair–deficient compared with mismatch repair–intact tumors (LAG-3: P<0.001; CD3: P<0.001). The majority (64%) of endometrial carcinomas demonstrated ≥1% tumoral GAL-3 expression, with higher rates in mismatch repair-deficient versus intact tumors at the ≥1% (80% vs. 32%, P<0.001) and the ≥5% thresholds (52% vs. 16%, P=0.003). At the ≥5% threshold, nonmethylated mismatch repair-deficient cancers were more likely than intact tumors carcinomas to express GAL-3 (60% vs. 4/25 16%, P=0.003). LAG-3+ lymphocytes were positively correlated with GAL-3 expression in nonmethylated mismatch repair-deficient endometrial carcinomas only (Spearman ρ=0.461, P=0.020). LAG-3+ tumor-associated lymphocytes and GAL-3+ neoplastic cells are common in endometrial carcinomas, particularly in nonmethylated mismatch repair-deficient cancers. This supports a role for immunotherapies targeting LAG-3 and/or GAL-3 in a subset of endometrial carcinomas, potentially in concert with other checkpoint inhibitors.

Equivalent Survival of p53 Mutated Endometrial Endometrioid Carcinoma Grade 3 and Endometrial Serous Carcinoma

TP53 status is the most important prognostic biomarker in endometrial carcinoma. We asked the question whether p53 mutated endometrial endometrioid carcinomas grade 3 (EEC3) or endometrial serous carcinomas (ESC), the latter ubiquitously harboring TP53 mutation, have different outcomes. TP53 mutation status was assessed by surrogate p53 immunohistochemistry on 326 EEC3 and ESC from 2 major cancer centers in Canada. Mutant-type p53 expression, including overexpression, complete absence, or cytoplasmic expression, was distinguished from the wild-type pattern. Statistical associations with clinico-pathological parameter, other key biomarkers, and survival analyses were performed. P53 mutant-type immunohistochemistry was observed in all 126 ESC and in 47/200 (23.5%) EEC3. ESC and p53 mutated EEC3 had an unfavorable outcome compared with p53 wild-type EEC3 (hazard ratio=2.37, 95% confidence interval=1.48–3.80, P=0.003, hazard ratio=2.19, 95% confidence interval=1.16–4.12, P=0.016, respectively) in multivariable analyses adjusted for age, stage, center, and presence of lymph-vascular invasion. There was no significant difference in survival between ESC and p53 mutated EEC3 in multivariable analysis. Furthermore, p53 mutated EEC3 and ESC almost completely overlapped in univariate survival analysis when mismatch repair (MMR)-deficient cases were excluded, which suggests that EEC3 harboring combined MMR deficiency and TP53 mutations behave more according to the MMR status. Significant differences between p53 mutated MMR-proficient EEC3 and ESC in PTEN and p16 expression status remained. p53 mutated, MMR-proficient EEC3 and ESC have overlapping survival significantly different from p53 wild-type EEC3, which justifies a similar treatment with current non-targeted standard therapy. Although this is so, separate classification should continue due to biological differences that will become important for future targeted therapy.

Somatically Derived Yolk Sac Tumor of the Ovary in a Young Woman

Ovarian carcinoma with a somatically derived yolk sac tumor component is a phenomenon known to mostly occur in postmenopausal women. Herein, we report an ovarian endometriosis-associated somatic yolk sac tumor arising in the background of a low-grade endometrioid adenocarcinoma in a young woman. A 27-yr-old woman presented with abdominal pain, subsequently recognized to be caused by a right ovarian mass undergoing torsion. Following operative management, microscopic examination of the salpingo-oophorectomy specimen showed endometriosis and a predominantly cystic ovarian neoplasm with 2 distinct phenotypic areas: (1) a yolk sac tumor component containing Schiller-Duval bodies and (2) a low-grade endometrioid carcinoma component with squamous metaplasia. Immunohistochemical evaluation showed distinct profiles in the yolk sac tumor (estrogen receptor/progesterone receptor/PAX8 negative, SALL4/Glypican 3 positive) and endometrioid (estrogen receptor/progesterone receptor/PAX8 positive, SALL4/Glypican 3 negative) components. Given these findings, the diagnosis of an endometriosis-associated endometrioid adenocarcinoma with a somatically derived yolk sac tumor was rendered. The tumor was staged as pT1c1 due to intraoperative spillage. The patient underwent chemotherapeutic treatment and after 15 mo of follow-up, she was alive with no evidence of recurrence. This example demonstrates that somatic yolk sac tumor differentiation in ovarian epithelial neoplasia can occur in young patients; awareness of this phenomenon is important as somatic and germ cell yolk sac neoplasia have different behavior and therapy.

First Case of Ovarian Metastases From a Primary Retroperitoneal Mucinous Carcinoma Associated With Teratoma, With KRAS and ERBB3 Mutations: Case Report and Literature Review

Primary retroperitoneal mucinous carcinomas (PRMCa) are exceedingly rare and poorly understood neoplasms, with <80 cases documented in the medical literature and molecular profiling hardly ever performed. Recent theories suggest that PRMCa might develop from mature cystic teratomas or Brenner tumors, mirroring their ovarian counterparts. However, only 2 cases of primary retroperitoneal mucinous tumors associated with teratoma have been reported in the literature to support this idea. In this paper, we detail an exceptional case: a 66-yr-old woman with ovarian metastases stemming from a PRMCa that originated in a mature cystic teratoma. The patient initially presented with a long-standing cystic mass in the retroperitoneum, diagnosed as a mucinous carcinoma after surgical removal. Following initial resection, the patient experienced rapid metastatic progression requiring aggressive treatment. Interestingly, the later ovarian metastases exhibited the full spectrum of architectural complexity observed in the initial lesion. This “maturation phenomenon,” frequently observed in ovarian metastases of mucinous tumors, remains enigmatic. Molecular analysis revealed a KRAS mutation along with an ERBB3 mutation, making it the first instance of ERBB3 mutation being documented in this specific entity. This case underscores the importance of thorough data collection and continued research to improve our understanding of these rare tumors.

Immunohistochemical Markers With Potential Diagnostic, Prognostic, and Therapeutic Significance in Uterine Carcinosarcoma: A Clinicopathologic Study of 43 Cases

Uterine carcinosarcomas (UCS) are rare and highly aggressive tumors. Although it is currently accepted that the majority of UCS are metaplastic carcinomas, their aggressive behavior is unparalleled to that of any other high-grade endometrial neoplasms. Therefore, the search for the distinct immunohistochemical and molecular features that could help in the development of new treatment strategies continues. We evaluated the expression of PDL-1, growth hormone releasing hormone receptor, p53, WT1, PAX-8, estrogen receptor, HNF-1, and mismatch repair proteins in 43 UCS. Tumors were selected from the archives of the Magee-Womens Hospital University of Pittsburgh Medical Center Department of Pathology. Seventeen were stage I, 4 were stage II, 15 were stage III, and 7 were stage IV. The median age was 67 yr and median overall survival was 3.2 yr. Immunostaining for PAX8, HNF-1, and estrogen receptor showed statistically significant difference between epithelial and stromal components. Expression of p53 was significantly associated with clinical high stage, but other markers did not correlate with stage or survival. Immunostaining for programmed death ligand-1 was strongly positive in 30 UCS (70%), including 24 cases with tumor cell positivity, 12 cases with tumor cell and tumor-infiltrating immune cell positivity, and 6 cases with tumor-infiltrating immune cell positivity only. Of 27 tumors tested for mismatch repair expression, 12 (44%) showed loss of expression, 7 of which were PDL-1 positive. Growth hormone releasing hormone receptor was positive in 38 tumors (88%) and predominantly expressed in the epithelial component. The range of positivity for programmed death ligand-1 and growth hormone releasing hormone receptor suggests a possible potential adjuvant treatment that may be considered for UCS.

Variable Expression of MSH6 in Endometrial Carcinomas With Intact Mismatch Repair and With MLH1 Loss Due to MLH1 Methylation

Immunohistochemistry for mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 is an effective screen to detect individuals at risk for Lynch syndrome. College of American Pathologists guidelines stipulate that protein expression should be reported as present versus absent, as most patients with germline mutations in a mismatch repair gene have complete loss of protein expression in tumor cells. A similar approach is employed to screen for cancer patients eligible for immune checkpoint blockade. This “all or none” interpretive approach ignores substantial evidence that mismatch repair may be more finely regulated by other mechanisms. We have observed clinically that MSH6 expression is variable, even in carcinomas that are overall considered positive for MSH6 expression. A proof-of-principle study was therefore designed to more rigorously quantify the protein expression of MSH6 and its binding partner, MSH2, using image analysis applied to age-matched endometrioid grade 2 subsets that were either mismatch repair intact or MLH1-deficient due to MLH1 gene methylation. In both endometrioid groups, MSH6 expression was significantly lower than MSH2 expression. MSH6 expression increased in higher grade, mismatch repair intact serous carcinomas, but it was still significantly lower than that for MSH2. MSH2 expression was consistently high across the 3 different tumor groups. These results suggest that MSH6 expression is subject to wide fluctuations in expression, even when overall its expression is considered intact. While such fluctuations are likely not relevant for Lynch syndrome screening, they may be more impactful when considering patients eligible for immune checkpoint blockade.

Endometrioid Tubal Intraepithelial Neoplasia (E-TIN) of the Fallopian Tube: A Case Series

Although serous tubal intraepithelial carcinoma has been well described in the distal fallopian tube as precancers of pelvic high-grade serous carcinoma, endometrioid precancers have drawn less attention. Recently, endometrioid precursor lesions have been identified and reported to have a specific immunophenotype (PAX2−, ALDH1+, diffuse nuclear beta-catenin), as well as an association with both uterine and ovarian endometrioid carcinomas. These have been referred to as endometrioid (or type II) secretory cell outgrowths. A subset of endometrioid secretory cell outgrowths show architectural complexity resembling hyperplasia of the endometrium and have been referred to as endometrioid tubal intraepithelial neoplasia. We report 4 cases of endometrioid tubal intraepithelial neoplasia with clinical correlation and morphologic differential diagnosis.

KRAS-mutated Uterine Endometrioid Carcinoma With Extensive Surface Changes Resulting in Striking Morphologic Mimicry of an Ovarian Serous Borderline Tumor

Surface epithelial changes involving endometrioid carcinomas of the uterine corpus mimicking papillary syncytial metaplasia or cervical microglandular hyperplasia are relatively common. There have been rare reports of surface epithelial changes in endometrioid carcinomas mimicking ovarian serous borderline tumor or low-grade serous carcinoma. We report an endometrioid carcinoma of the uterine corpus with striking morphologic mimicking of an ovarian serous borderline tumor with only a minimal amount of conventional endometrioid carcinoma. The tumor was diffusely positive for estrogen receptor, negative for WT1, and showed wild-type immunoreactivity with p53. Targeted sequencing revealed a KRAS mutation (G12V/D/A), but no BRAF mutation. This close mimicry of a serous borderline tumor by a uterine endometrioid carcinoma has not been emphasized in the literature and this case is unique because the features involved almost the entire neoplasm. In reporting this case, we review surface changes in endometrioid carcinomas of the uterine corpus.

Presence of Glandular Cells at the Preoperative Cervical Cytology and Local Recurrence in Endometrial Cancer

We investigated the correlation between glandular cells (GC) detected at preoperative cervical-smear and the histologic findings and oncologic outcomes in patients undergoing surgery for endometrial cancer (EC). We retrospectively analyzed data of all consecutive EC patients who underwent surgery between January 1, 1990 and December 31, 2012 with preoperative cervical smear performed within 3 mo from the EC diagnosis. Basic descriptive, logistic regression and artificial neural network analyses were used. Five-year disease-free survival and overall survival were assessed using Kaplan-Meier and Cox hazard models. The study included 229 (89%) and 29 (11%) patients with normal cytology (control group) and GC (GC group), respectively. A higher proportion of elderly patients with nonendometrioid and FIGO grade 3 EC was observed in the GC group compared with the control group (P<0.05). No differences in 5-yr disease-free survival and overall survival were observed. However, patients in the GC group experienced a higher local recurrence rate (hazard ratio: 7.6; 95% confidence interval: 1.7–34.2; P=0.008). We observed that age, body mass index, cervical stromal invasion, vaginal brachytherapy, and GC influenced the risk for developing local recurrence. However, at the multivariable analysis, only cervical stromal invasion (odds ratio: 1.2; 95% confidence interval: 1.02–1.4; P=0.02) and GC (odds ratio: 1.07; 95% confidence interval: 1.01–1.14; P=0.03) correlated with the increased risk. In addition, the results of an artificial neural network analysis reported that the most critical predictor of local failure was cervical stromal invasion (importance: 0.352) followed by GC (importance: 0.194). These results suggest that cervical stromal invasion and presence of GC at the preoperative cervical smear might predict the occurrence of local recurrence in EC.

Diagnostic Variation in p53 Usage for Endometrial Carcinoma Diagnosis: Implications for Molecular Subtyping

Immunostaining for p53 is widely but variably used when diagnosing endometrial carcinoma (EC). Mutant-pattern p53 staining can support a diagnosis of serous carcinoma, and also serve as a surrogate test for identifying the “serous-like” subset of aggressive EC identified by The Cancer Genome Atlas characterized by high numbers of somatic copy number abnormalities. We, retrospectively, assessed WHO histotype, usage of p53 immunostaining, and p53 status in a consecutive series of biopsies showing EC from a single hospital. Of 79 ECs, 59 (75%) were low-grade EC (LGEC), 13 (16%) high-grade EC (HGEC), and 7 (9%) were serous. p53 immunostaining was performed at the time of diagnosis in 27/79 (34%) biopsies; 6/7 of serous histotype, 11/13 HGEC, and 10/59 LGEC. Mutant-pattern p53 staining was present in 6/6 serous, 2/11 HGEC, and 2/10 LGEC. The remaining 53 tumors subsequently had p53 immunostaining done; all 49 LGEC showed wild-type staining and the serous carcinoma and 1/2 HGEC showed mutant pattern staining. While there are no guidelines on using p53 in endometrial biopsies, this study shows consistent usage in high-grade histotypes and variable usage in LGEC. As 100% (7/7) of serous EC and 3% (2/59) of the LGECs showed mutant-pattern p53 staining, histotype may serve as a surrogate for p53 assessment, such that only HGEC or ambiguous carcinomas should be routinely subjected to p53 immunostaining.

Vaginal Low-Grade Endometrial Stromal Sarcoma: An Extremely Rare Case Report and Review of the Literature

Endometrial stromal sarcoma (ESS) is a malignant tumor of the uterus that has been described as the second most common malignant uterine mesenchymal tumor. Primary extrauterine ESS (EESS) is an extremely uncommon occurrence. We hereby report a new bona fide case of low-grade EESS in a 74-yr-old woman arising in the vagina, presenting as a polypoid mass associated with irregular vaginal bleeding. On examination, a 6×2×2 cm polypoid mass was found in the left vaginal wall. Consequently, the patient underwent partial vaginectomy and repair. No ESS or endometriotic lesion was found in the endometrium and bilateral adnexa. The diagnosis of ESS performed by typical pathologic and immunohistochemical evaluation was as follows: beta-catenin (+++), estrogen receptor (+++), progesterone receptor (++), vimentin (++), and uniformly negative for CD10, EMA, CD31, CD34, CD117,CD99, SMA, desmin, h-caldesmon, S-100, MelanA, and HMB45. She has remained disease free with no signs or symptoms of recurrent or advanced disease for 46 mo. Although CD10 is the most useful immunohistochemical marker for the diagnosis of this tumor, negative CD10 staining can be encountered with underfixation. Therefore, it is important to use a panel of immunostains that includes CD10, beta-catenin, and smooth muscle markers. The present study describes the clinical and pathologic features of low-grade EESS through a case report and literature review. To the best of our knowledge, this is the eighth report of EESS arising from the vagina.

Sarcomatous Transformation in Undifferentiated/Dedifferentiated Endometrial Carcinoma: An Underrecognized Phenomenon and Diagnostic Pitfall

Undifferentiated/dedifferentiated carcinoma is an aggressive endometrial carcinoma which remains underrecognized but may account for up to 9% of all endometrial malignancies. We describe 3 cases in which the undifferentiated component was associated with sarcomatous differentiation, characterized by spindled cells in 2 cases and heterologous malignant cartilage in 1 case. Two of the 3 cases demonstrated mismatch repair deficiency by immunohistochemistry. This phenomenon has not previously been formally reported and increases the likelihood of misdiagnosis, especially within biopsy samples; differential diagnoses may include endometrial stromal sarcoma and grade 3 endometrioid adenocarcinoma with spindled morphology. We review the current literature and provide strategies for resolving the differential diagnoses, with a suggested panel of antibodies which includes EMA, E-cadherin, and mismatch repair proteins as approximately 50% of cases show loss of mismatch repair expression.

Xanthogranulomatous Salpingitis

There are approximately a dozen cases of xanthogranulomatous salpingitis reported in the literature, mostly as case reports. Thirteen such cases were identified from 2003 to 2018 at our institution. Patient’s ages ranged from 21 to 75 yr old (median and mean, 49 yr). Clinical presentations and surgical indications included pelvic inflammatory disease (5 cases), endometrial carcinoma (4 cases), suspicion of ovarian malignancy (1 case), symptomatic fibroids (1 case), endometriosis (1 case), and infertility (1 case). Surgical-pathologic correlation resulted in diagnoses of tubo-ovarian abscess (4 cases), ovarian abscess (2 cases), pyosalpinx (2 cases), and chronic endometritis (2 cases). Of the remaining 3 cases, 2 presented clinically as pelvic inflammatory disease and the other was seen in the context of an endometrial carcinoma. In summary, this case series from a single institution shows that xanthogranulomatous salpingitis is an uncommon form of chronic inflammation that may be diagnosed from reproductive to menopausal age. With one exception, the cases in this series represent pelvic inflammatory disease despite variable clinical presentations. Pseudoxanthomatous salpingitis should be in the differential diagnosis.

Primary Peritoneal Low-grade Serous Carcinoma in a Patient With Lynch Syndrome: A Case Report

Lynch syndrome (LS) is an autosomal dominant disease caused by a germline mutation in DNA mismatch repair genes which increases the risk of several cancers such as endometrial and colorectal cancers. However, there are only a few reports of peritoneal malignancies in patients with LS. Herein, we report the first case of a primary peritoneal low-grade serous carcinoma in a woman with LS and provide a literature review of peritoneal malignancies in patients with LS. The patient was a 72-yr-old gravid 2 para 2 Japanese woman with a germline mutation in MLH1. She had a history of colon cancer and endometrial cancer and was treated with total hysterectomy and bilateral salpingo-oophorectomy 14 yr ago. During the follow-up, peritoneal nodules were detected by abdominal computed tomography which were surgically resected. Pathologic examination revealed a low-grade serous carcinoma with cells positive for BerEP4, MOC31, CEA, and WT-1 and negative for BAP1, PAX8, MLH1, and PMS2, by immunohistochemistry. This case report and literature review show that peritoneal low-grade serous carcinoma can occur in patients with LS and that LS-related cancers usually precede primary peritoneal malignancies. The differential diagnosis for peritoneal nodules in patients with LS should, therefore, include peritoneal serous carcinoma and malignant mesothelioma besides metastasis of LS-related cancers. Considering the ambiguous immunophenotypes, a combination of immunohistologic markers would be useful for an accurate diagnosis of such cases.

A New Classification of Benign, Premalignant, and Malignant Endometrial Tissues Using Machine Learning Applied to 1413 Candidate Variables

Benign normal (NL), premalignant (endometrial intraepithelial neoplasia, EIN) and malignant (cancer, EMCA) endometria must be precisely distinguished for optimal management. EIN was objectively defined previously as a regression model incorporating manually traced histologic variables to predict clonal growth and cancer outcomes. Results from this early computational study were used to revise subjective endometrial precancer diagnostic criteria currently in use. We here use automated feature segmentation and updated machine learning algorithms to develop a new classification algorithm. Endometrial tissue from 148 patients was randomly separated into 72-patient training and 76-patient validation cohorts encompassing all 3 diagnostic classes. We applied image analysis software to keratin stained endometrial tissues to automatically segment whole-slide digital images into epithelium, cells, and nuclei and extract corresponding variables. A total of 1413 variables were culled to 75 based on random forest classification performance in a 3-group (NL, EIN, EMCA) model. This algorithm correctly classifies cases with 3-class error rates of 0.04 (training set) and 0.058 (validation set); and 2-class (NL vs. EIN+EMCA) error rate of 0.016 (training set) and 0 (validation set). The 4 most heavily weighted variables are surrogates of those previously identified in manual-segmentation machine learning studies (stromal and epithelial area percentages, and normalized epithelial surface lengths). Lesser weighted predictors include gland and lumen axis lengths and ratios, and individual cell measures. Automated image analysis and random forest classification algorithms can classify normal, premalignant, and malignant endometrial tissues. Highest predictive variables overlap with those discovered independently in early models based on manual segmentation.

Synchronous Well-differentiated Endometrioid Adenocarcinoma and Leiomyosarcoma of the Uterus With Pulmonary Metastasis in a 50-Yr-Old Woman: A Case Report and Review of Literature

The most common synchronous gynecologic malignancies are endometrial and ovarian cancers. However, synchronous endometrial adenocarcinoma and uterine leiomyosarcoma are extremely rare. We report the case of a 50-yr-old woman who was diagnosed with concomitant endometrial adenocarcinoma and uterine leiomyosarcoma. The sarcomatous neoplasm was positive for anti-smooth muscle actin and CD10, and focally positive for Cytokeratin AE1/AE3 and Cytokeratin Cam 5.2. She underwent total abdominal hysterectomy with bilateral salpingoopherectomy followed by radiation, brachytherapy, and chemotherapy. Three years later, she presented with cough and dyspnea and was found to have pulmonary metastasis. These tumor cells were positive for anti-smooth muscle actin, Cytokeratin AE1/AE3, Cytokeratin Cam 5.2, and epithelial membrane antigen, and therefore a diagnosis of lung metastasis from myometrial leiomyosarcoma was made. She received chemotherapy postoperatively. Currently, the patient has multiple lung metastases, is on Megestrol Acetate and is clinically well. This is the first reported case of concomitant uterine malignancies with pulmonary metastases and a long follow-up of 9 yr. It is important to rule out carcinosarcoma as a differential diagnosis in such patients.

Distinct Histologic, Immunohistochemical and Clinical Features Associated With Serous Endometrial Intraepithelial Carcinoma Involving Polyps

The origin of serous endometrial intraepithelial carcinoma (SEIC) is debated, due to its premalignant and independently malignant nature. It often arises next to endometrial serous carcinoma (ESC), with a propensity for polypoid growth. We aimed to better characterize this discrepancy by analyzing the clinical, histologic, and immunohistochemical features of polypoid carcinoma associated with SEIC (P-SEIC), and compared them with usual endometrial serous carcinoma without SEIC (UESC). Consecutive patients with P-SEIC were recruited and compared with UESC controls from our institutional research center. Clinical, histologic, and immunohistochemical (IHC, ER, PR, P53, Napsin-A, WT1, P16) were analyzed. BRCA testing results and familial history were also extracted from clinical databases. Welch T test, Pearson χ2, and Fisher exact test were performed in SPSS version 23. A total of 37 P-SEIC and 25 UESC were the basis of a case-control study. P-SEIC was associated with more bilateral ovarian involvement (P=0.026), yet showed lower rates of myometrial invasion (P=0.002). P-SEIC showed a statistically different IHC profile: p53+, p16+, ER+, PR+, and WT-1+, and high rates of Napsin-A, while UESC was p53+, p16+, WT-1−, Napsin-A−, with lower rates of ER and PR. We also identified 2 patients who received prophylactic salpingo-oophorectomy for BRCA mutations and who subsequently developed P-SEIC with its unique IHC pattern. Our results suggest different underlying expression profiles and possibly diverging molecular signatures between both P-SEIC and UESC. If confirmed in further molecular studies, it could lead to a distinct molecular subclass.

Use of Immunohistochemical Markers (HNF-1β, Napsin A, ER, CTH, and ASS1) to Distinguish Endometrial Clear Cell Carcinoma From Its Morphologic Mimics Including Arias-Stella Reaction

The diagnosis of clear cell (CC) carcinoma of the endometrium can be challenging, especially when endometrioid (EC) and serous (SC) endometrial cancers exhibit nonspecific clear cell changes, in carcinomas with mixed histology and in the setting of Arias-Stella reaction (ASR). In this study, classic CC immunohistochemical markers (Napsin A, HNF-1β, and ER) and 2 recent novel markers, cystathionine gamma-lyase (CTH) and arginosuccinate synthase (ASS1), are assessed for their utility in distinguishing CC from its morphologic mimics. Tissue microarrays containing 64 CC, 128 EC, 5 EC with clear cell change, 16 SC, 5 mixed carcinomas, and 11 whole ASR sections were stained, with 12 additional examples of ASR stained subsequently. A cutoff of 70% and moderate intensity were used for HNF-1β, 80% of cells and strong intensity were used for CTH, and any staining was considered positive for the remaining markers. For differentiating CC from pure EC and SC, HNF-1β, Napsin A, and CTH all performed well. HNF-1β had higher specificity (99.3% vs. 95.1%) but lower sensitivity (55.8% vs. 73.1%) compared with Napsin A. CTH did not substantially outperform HNF- 1β or Napsin A (sensitivity 51.9%, specificity 99.3%). ASS1 and ER were not helpful (specificities of 60.1% and 22.6%). For differentiating CC from ASR, HNF-1β, Napsin A, and CTH stained a large proportion of ASR and were not useful. However, ER positivity and ASS1 negativity were helpful for identifying ASR (specificity 88.2% and 95.1%, respectively). EC with clear cell changes exhibited immunohistochemical patterns similar to pure EC (HNF-1β−, ER+, and CTH−). No markers were useful in confirming the CC components in mixed carcinomas.

Is It Possible to Develop a Prediction Model for Lymphovascular Space Invasion in Endometrioid Endometrial Cancer?

Objective The purpose of this retrospective study was to define a risk index that would serve as a surrogate marker of lymphovascular space invasion (LVSI) in women with endometrioid endometrial cancer (EC). Materials and Methods Final pathology reports of 498 women who underwent surgery with curative intent for endometrioid EC between January 2008 and June 2018 were retrospectively reviewed. Logistic regression was used to investigate clinicopathologic factors associated with positive LVSI status. Independent risk factors for LVSI were used to build a risk model and “risk of LVSI index” was defined as “tumor grade×primary tumor diameter×percentage of myometrium involved.” The scores used in the “risk of LVSI index” were weighted according to the odds ratios assigned for each variable. The risk of LVSI index was noted for each patient. The diagnostic performance of the model was expressed as sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio. Results According to the “risk of LVSI index,” presence of LVSI was correctly estimated in 89 of 104 LVSI-positive women at a cutoff of 161.0 (sensitivity 85.5%, specificity 79.4%, negative predictive value 95.4%, positive predictive value 52.3%, positive likelihood ratio 4.15, negative likelihood ratio 0.18). The area under curve of the receiver-operating characteristics was 0.90 (95% confidence interval, 0.87–0.93) at this cutoff. Conclusions It seems possible to predict the presence of LVSI in women with endometrioid EC when the “risk of LVSI index” is calculated. However, external validation of this model is warranted.

Interpretation of Mismatch Repair Protein Immunohistochemistry in Endometrial Carcinoma Should Consider Both Lynch Syndrome Screening and Immunotherapy Susceptibility: An Illustrative Case Report

We present an instructive case of FIGO grade 1 endometrioid endometrial carcinoma with a biphasic morphology, corresponding to subclonal loss of mismatch repair proteins (MMRP) MLH1 and PMS2 by immunohistochemistry and subclonal microsatellite instability. A pulmonary metastasis represented only the tumor component with retention of MMRPs. This case illustrates the need for pathologists to recognize and report heterogenous expression of MMRPs in endometrial carcinoma, to consider tumor heterogeneity when selecting foci for molecular studies, and to re-evaluate MMRP expression in tumor metastases, when clinically indicated. These considerations are particularly important as the relevance of MMRP expression in endometrial cancer expands beyond Lynch syndrome screening, into a new role as a predictive marker for immunotherapy.

Dedifferentiated Carcinoma of the Endometrium Associated With Low-grade Müllerian Adenosarcoma: A Clinicopathologic Case Report Including the Immunohistochemical and Molecular Profile

Dedifferentiated carcinoma is defined as undifferentiated carcinoma coexisting with a second component of FIGO grade 1 or 2 endometrioid carcinoma. It is a rare entity with highly aggressive behavior. Dedifferentiated carcinoma combined with another primary uterine tumor is even rarer. We describe a case containing 3 different morphologies comprised of a dedifferentiated carcinoma associated with a low-grade endometrioid carcinoma coexisting with a low-grade Müllerian adenosarcoma. We also used targeted genomic analysis to show all 3 components arise from the same founding clone and identify novel mutations that drive tumor progression.

Molecular Classification and Emerging Targeted Therapy in Endometrial Cancer

Recent advances in molecular studies, especially genome-wide analyses, have revealed the landscape of genomic alterations present in endometrial carcinomas, and have provided valuable insight into the pathogenesis of this disease. The current challenges are in developing a molecular-morphologic classification system to enhance traditional pathologic diagnosis and in determining the optimal approach to using this new information to guide clinical management. Molecular assays may be particularly beneficial in allowing the earlier detection of endometrial cancer or precursor lesions and in guiding personalized treatment approaches. In this review, we describe the current molecular landscape of endometrial cancers, efforts underway to incorporate molecular alterations into the current classification systems, and the development of diagnostic tools for the early detection of endometrial cancer. Finally, we present opportunities for using these data to tailor therapeutic strategies. A comprehensive understanding of the molecular alterations responsible for the origination, relapse, and resistance patterns of this disease will ultimately improve outcomes for patients with endometrial cancer.

Clinicopathologic and Immunohistochemical Correlates of CTNNB1 Mutated Endometrial Endometrioid Carcinoma

Endometrial endometrioid carcinomas (EECs) with exon 3 CTNNB1 mutations characterize a more aggressive subset of tumors in patients with low-grade low-stage disease. Thus, prospectively identifying these cases may be clinically relevant. The aim of this study was to examine the feasibility of β-catenin and Cyclin D1 immunohistochemistry to identify EECs harboring CTNNB1 mutations and to evaluate the clinicopathologic features of EECs with exon 3 CTNNB1 mutations. Thirty-nine CTNNB1 mutated EECs and 40 CTNNB1 wild-type EECs were identified from a cohort of previously sequenced endometrial carcinomas using a targeted next-generation sequencing panel. Immunohistochemistry for β-catenin and Cyclin D1 was performed on all cases. Immunohistochemistry results were correlated with CTNNB1 mutation status and clinicopathologic parameters. Patients with CTNNB1 mutated EECs were younger than those with CTNNB1 wild-type (56.2 vs. 61.5 y; P=0.033). Nuclear β-catenin expression correlated with exon 3 CTNNB1 mutation (P<0.0001) with a sensitivity of 91% and a specificity of 89%. Cyclin D1 expression correlated with CTNNB1 exon 3 mutation with relatively high specificity (90%) but low sensitivity (29%). Recurrence rate in patients with stage IA disease at diagnosis was significantly higher in patients whose tumors were CTNNB1 mutated compared with CTNNB1 wild-type (30% vs. 0%; P=0.025) and included distant metastases; all recurrent tumors in this group harbored exon 3 mutations and were histologically low grade (5 grade 1, 2 grade 2). Nuclear β-catenin expression appears to be an acceptable proxy for CTNNB1 mutation.

Endometrial Endometrioid Carcinoma With Ovarian Metastasis Showing Morula-like Features in a Patient With Cowden Syndrome: A Case Report

Cowden syndrome (CS) is a multiple hamartoma syndrome associated with the development of various tumors, including endometrial cancer. However, the histology of CS-associated endometrial cancer remains to be fully described. To our knowledge, this is the first report of a patient with CS having endometrial endometrioid carcinoma with ovarian metastasis demonstrating morula-like features. A 31-yr-old, nulliparous, Japanese woman presented with abnormal genital bleeding. Endometrial biopsy revealed endometrioid carcinoma with an extensive morular formation, partially resembling atypical polypoid adenomyoma (APAM). Moreover, she had a past history of bilateral breast cancer and a family history of juvenile breast cancer in her mother. Genetic testing revealed they shared the same pathogenic germline PTEN mutation. She underwent an abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node biopsy. Pathologic examination revealed endometrial endometrioid carcinoma with APAM-like histology. Furthermore, the solid components with morula-like morphology and immunophenotypes showed myometrial invasion and ovarian metastasis (FIGO stage IIIA/pT3aN0M0). The present case highlights the need for careful assessment of myometrial invasion and extrauterine spread for appropriate gynecologic treatment even if endometrial biopsy shows APAM-like histology. Moreover, characterization of CS-associated endometrial cancers is required.

Rare Primary Fallopian Tube Grade 2 Neuroendocrine Tumor: A Case Report With Review of Literature

Neuroendocrine neoplasms commonly arise from the gastrointestinal tract and lungs. Less commonly, they may occur in the gynecologic tract, typically within the ovary of a mature cystic teratoma. Primary neuroendocrine neoplasms of the fallopian tube are exceptionally rare and only a total of 11 cases have been reported in the literature. We describe the first case to our knowledge of a primary grade 2 neuroendocrine tumor of the fallopian tube in a 47-yr-old female. In this report, we describe the case’s unique presentation, review the published literature on primary neuroendocrine neoplasms of the fallopian tube, discuss the treatment options, and speculate on their origin and histogenesis.

Serous Tubal Intraepithelial Carcinoma in a Risk-reducing Salpingo-oophorectomy Specimen From a RAD51D Mutation Carrier: A Case Report

The RAD51D gene codes a protein-paralog of the RAD51 DNA recombinase, which catalyzes DNA strand exchange during homologous recombination. Similar to BRCA1/BRCA2, mutations in RAD51D both predispose to ovarian carcinoma and impart sensitivity to poly (ADP-ribose) polymerase inhibitors in preclinical studies. Based on cancer risk prediction models, RAD51D mutations pose a moderate-to-high risk for ovarian cancer warranting consideration for risk-reducing surgery. We report a case of serous tubal intraepithelial carcinoma in a patient undergoing risk-reducing total hysterectomy with bilateral salpingo-oophorectomy for a RAD51D pathogenic variant. The histopathologic and p53-immunophenotypic features of this lesion are similar to those reported previously in BRCA1/BRCA2 mutation carriers and those of serous tubal intraepithelial carcinoma associated with sporadic high-grade serous carcinomas. These features include marked increase in nuclear-to-cytoplasmic ratio, loss of cell polarity, absence of ciliation, prominent nucleoli, mitotic activity, epithelial stratification, surface exfoliative changes, and complete loss of p53 staining. Although familial ovarian cancers with mutations in RAD51D—or other genes in the Fanconi anemia pathway—are much less common those with BRCA1/BRCA2 mutations, our findings support a common phenotype for early serous cancers in this pathway.

Immunohistochemical Expression Status of p53, CD44v9, and Ki-67 in a Series of Fallopian Tube Lesions of High-grade Serous Carcinoma

Pelvic high-grade serous carcinoma (HGSC) has been postulated to arise via a stepwise accumulation of (epi)genetic alterations from normal epithelium to secretory cell outgrowth (SCOUT), p53 signature, and serous tubal intraepithelial carcinoma (STIC) to invasive HGSC. The aim of this study is to investigate alterations in p53 and CD44v9 expression and the status of Ki-67 labeling index in a series of fallopian tube lesions of HGSC patients. A total of 45 specimens were analyzed in 16 patients with HGSC, and their lesions were categorized as follows: morphologically normal fallopian tube epithelium (FTE, n=6 samples), SCOUT (n=5), p53 signature (n=4), dormant STIC (n=8), active STIC (n=6), and HGSC (n=16). Morphologic features and immunohistochemical expression patterns of the p53 protein, CD44v9 protein, and Ki-67 antigen were blindly evaluated by 2 pathologists. Increased nuclear p53 protein accumulation was observed in p53 signature, dormant STIC, active STIC and HGSC compared with normal FTE and SCOUT (P<0.001). Immunohistochemistry scores of CD44v9 protein expression were significantly higher in normal FTE, SCOUT, and p53 signature than in dormant STIC, active STIC, and HGSC (P<0.001). Both active STIC and HGSC had significantly higher Ki-67 labeling indices than normal FTE, SCOUT, p53 signature and dormant STIC (P<0.001). CD44v9 loss contributes to the stepwise progression of p53 signature to dormant STIC. In conclusion, p53 mutation followed by CD44v9 loss may be involved in the evolution of STIC, which may confer positive clonal selection with a growth and survival advantage.

Adenomatoid Tumor of Fallopian Tube With “Deciduoid” Morphology and Atypical Nuclear Features

Adenomatoid tumor is a benign neoplasm of mesothelial origin. Adenomatoid tumor in female genital tract shows typical morphologic features with bland nuclei. Deciduoid morphology has not been reported in adenomatoid tumor. Tumors with deciduoid cells and atypical nuclear features may pose a diagnostic challenge and raise the suspicion of malignancy. We present a case of fallopian tube adenomatoid tumor with deciduoid morphology and atypical nuclear features in a 39-year-old woman with prolonged progestin therapy. We hypothesize that the unusual morphological changes in adenomatoid tumor, like deciduoid morphology and nuclear atypia, may be secondary to hormone effects.

Ovarian Mixed Epithelial Carcinoma With Extensive Bilateral Fallopian Tubes Metastases by the Low-grade Serous Carcinoma Component Mimicking Serous Tubal Intraepithelial Carcinoma: Case Presentation and Literature Review

Seromucinous carcinoma of the ovary was a newly defined category in the revised 2014 World Health Organization Classification of Tumors of Female Reproductive Organs. It was defined as a carcinoma composed of predominantly of serous and endocervical-type mucinous epithelium. Foci containing clear cells, and areas of endometrioid and squamous differentiation are not uncommon. It is a rare entity with morphologic and immunophenotypic features overlapping other types of ovarian carcinoma. There are different opinions as to whether it is a distinct entity or a histologic variant of well-established entities. Subsequent, to the writing of this manuscript the WHO 2020 reclassified this tumor as a type of endometrioid carcinoma. Here we present a case of seromucinous carcinoma of bilateral ovaries that had variable differentiation and morphology at different sites. Tumor in the fallopian tubes, ovarian surfaces, omentum, and peritoneal surfaces displayed predominant features of low-grade serous carcinoma, while the tumor in the ovaries had predominant mucinous carcinoma morphology with a confluent/expansile growth pattern. The mucosal involvement of the fallopian tubes morphologically mimicked serous tubal intraepithelial carcinoma.

A Case Report of Incidental Primary Leiomyosarcoma of the Fallopian Tube and a Review of the Recent Literature

Primary leiomyosarcoma of the fallopian tube is a very rare neoplasm with descriptions limited to case reports. We present the case of a 46-yr-old woman with a history of renal transplantation in whom a primary leiomyosarcoma of the fallopian tube was identified incidentally following hysterectomy and bilateral salpingectomy undertaken for a uterine fibroid. The tumor demonstrated classic morphological and immunohistochemical features of a leiomyosarcoma. It appeared localized to the fallopian tube and was completely resected. Adjuvant therapy was not given but active surveillance initiated. After 14 mo of follow-up, there was no evidence of disease recurrence. We review cases from the past 20 yr with a focus on management and outcomes. Given the rarity of this disease, continued publication of case reports and the creation of a centralized case registry would be of benefit.

Impact of Ki-67 Labeling Index on Prognostic Significance of the Chemotherapy Response Score in Women With Tubo-ovarian Cancer Treated With Neoadjuvant Chemotherapy

The chemotherapy response score (CRS) proposed by Bohm and colleagues in 2015 has been validated as a reproducible method for determining histopathologic response of tubo-ovarian carcinoma to neoadjuvant chemotherapy and stratifies tumor response into 3 groups: CRS1 is defined as minimal/no response, CRS2 as moderate response, and CRS3 as marked response. Although described as a 3-tiered system, it essentially works as a 2-tiered system (CRS1/CRS2 vs. CRS3) for assessing prognosis. Here, we analyzed the prognostic value of CRS in a large cohort of tubo-ovarian carcinomas at a tertiary care center and evaluated the potential for Ki-67 labeling index on post-neoadjuvant chemotherapy samples to provide additional prognostic information. We included 170 patients with tubo-ovarian carcinoma treated with neoadjuvant chemotherapy followed by interval debulking surgery. We determined CRS for each case by reviewing slides from the interval debulking surgery resection specimen and calculated progression-free survival and overall survival. For each case with residual disease (CRS1 and CRS2, n=123, 72%), we also performed Ki-67 antibody staining and determined both average and highest Ki-67 labeling index. Consistent with prior studies, patients in our cohort with CRS1 and CRS2 showed significantly shorter progression-free survival and overall survival compared with CRS3. Further, in the subset of cases with CRS1 and CRS2, Ki-67 labeling index was predictive of OS at multiple cutoff points. An average Ki-67 labeling index of 20% (log rank test P-value: 0.0004) or a highest Ki-67 labeling index of 50% (log rank test P-value: 0.0002) could provide a practically useful cutoff. Multivariable cox proportional hazard model showed worse overall survival with both, average Ki-67 >20% (hazard ratios: 2.02, P-value: 0.00422, confidence interval: 1.25–3.28) and highest Ki-67 >50% (hazard ratios: 1.88, P-value: 0.0205, confidence interval: 1.1–3.2). We propose adding Ki-67 labeling index to CRS to provide additional prognostic separation between patients with CRS1 and CRS2.

Leydig Cells in the Fallopian Tube and Walthard Cell Nests in the Ovary: Heterotopia or Eutopia?

An Alternate Diagnostic Algorithm for the Diagnosis of Intraepithelial Fallopian Tube Lesions

Intraepithelial fallopian tube neoplasia is thought to be a precursor lesion to high-grade serous carcinoma of the Müllerian adnexae, particularly in women with BRCA1 or BRCA2 mutations. This association has led to recommendations to assess fallopian tubes for intraepithelial atypia. However, the diagnostic reproducibility of a diagnosis of intraepithelial neoplasia is unclear. In this study, 2 gynecologic pathologists independently evaluated sections of fallopian tubes from a sample of women (N=198, 623 slides) undergoing salpingectomy. A total of 101 (54%) women were undergoing risk-reducing salpingo-oophorectomy. Pathologists were blinded to patient histories and prior diagnoses. Pathologists rendered one of three diagnoses for each slide: “negative for fallopian tube intraepithelial neoplasia (FTIN),” “indeterminate for FTIN,” or “definite for FTIN.” Cases that were considered by histology definite for FTIN or suspicious for FTIN were stained with p53 and Ki67. Pathologists agreed on the diagnosis of “definite for FTIN” 61.5% of the time. There was no agreement on any cases for the diagnosis of “indeterminate for FTIN.” Fifteen “indeterminate for FTIN” and 12 “definite for FTIN” cases were stained with p53 and Ki67. Two of the “indeterminate” cases (13%) had p53-positive foci. Five of the “definite” cases had p53-positive foci. In 3 of the other 8 “definite” cases, there was obvious carcinoma present, but the carcinoma did not stain with p53, suggesting a possible null phenotype. We propose that immunostains should only be used to aid in the diagnosis of FTIN in cases with indeterminate histology. The use of p53 immunohistochemistry in cases that were considered “definite for FTIN” by histology was minimally helpful, and in fact often served to further confuse the diagnosis.

Lymphatic Invasion in the Fallopian Tube is a Late Event in the Progression of Pelvic Serous Carcinoma and Correlates With Distant Metastasis

The majority of extrauterine high-grade serous carcinomas are believed to arise in the fallopian tube as serous tubal intraepithelial carcinomas. The primary mode of metastasis is intraperitoneal, and patients usually present with peritoneal carcinomatosis. Although the tubes have a rich lymphatic network, tubal lymphatic invasion is observed in only a minority of cases. Fallopian tube sections from 222 patients with advanced stage high-grade extrauterine serous carcinoma were reviewed and lymphatic invasion within the lamina propria and myosalpinx were assessed. Seventeen patients were FIGO stage II, 162 stage III, and 43 stage IV. Tubal lymphatic invasion was identified in 44 cases (19.7%). Among the cases with lymphatic invasion, nonfimbrial lamina propria, fimbrial lamina propria, and myosalpingeal lymphatic invasion were present in 23 (52%), 21 (48%), and 21 (48%), respectively. Among cases with lymphatic invasion, 16 (36%) were FIGO stage IV, while among cases without lymphatic invasion, 27 (15%) were stage IV (P=0.0014, χ2). In summary, in women with advanced stage high-grade extrauterine serous carcinoma, lymphatic invasion in the fallopian tube is uncommon, and is more than twice as likely to be associated with distant metastases as compared with those without tubal lymphatic invasion.

Low-grade Serous Carcinoma Arising in Inguinal Nodal Endosalpingiosis: Report of 2 Cases and Literature Review

We report 2 cases of low-grade serous carcinoma probably arising from endosalpingiosis within inguinal lymph nodes. The neoplasms occurred in 51- and 58-yr old women in the absence of tumor within the adnexa, peritoneum or elsewhere. These represent the first reported examples of low-grade serous carcinoma arising within and confined to inguinal nodes. We review the pertinent literature regarding primary nodal low-grade serous carcinoma.

Ovarian Sclerosing Stromal Tumor and Müllerian Cyst in an 11-yr-old Girl: A Case Report and Review of the Literature

Sclerosing stromal tumor (SST) is an extremely rare ovarian neoplasm that primarily affects young female individuals. Patients with SST often present with pelvic pain and menstrual irregularities. Herein, we report a case of SST of the ovary in an 11-yr-old girl with symptoms of abdominal pain and menstrual irregularities. A preoperative diagnosis of tumors in the left adnexa and right ovary was made by pelvic ultrasonography and magnetic resonance imaging, and the patient underwent exploratory laparotomy and laparoscopic cystectomy. The ovarian masses were removed and proven to be SST in the left ovary and Müllerian cyst in the right fallopian tube on histopathologic examination and immunochemistry. To our knowledge, the 11-yr-old patient presented here was the only case with SST and Müllerian cyst simultaneously.

Microscopic Sertoliform Sex Cord Proliferation Involving Pelvic Peritoneum: Report of a Case Associated With Endosalpingiosis

Microscopic sex cord proliferations are an uncommon finding, most often associated with ovarian or uterine stromal, epithelial, or mixed epithelial and stromal neoplasms. Rarely they occur in conjunction with a non-neoplastic process such as endometriosis or adenomyosis, and occasionally in the absence of concurrent pathology in locations such as the fallopian tube. Most reports of this phenomenon document adult granulosa cell tumor-like morphology but more uncommonly the proliferations exhibit Sertoliform features. We report a case of a multifocal sex cord proliferation (inhibin and calretinin positive; BerEP4 and epithelial membrane antigen negative) with Sertoliform features occurring in the pelvic peritoneum and associated with endosalpingiosis, a previously unreported phenomenon. We discuss the differential diagnosis and speculate that this represents a non-neoplastic phenomenon.

Estrogen Receptor (ER) and Progesterone Receptor (PR) Immunohistochemistry is Sensitive and Specific for Differentiating Retroperitoneal Leiomyosarcomas With Symplastic-like Features From Their Uterine Mimics

Previous studies have evaluated the utility of estrogen receptor (ER) and progesterone receptor (PR) immunohistochemistry (IHC) in differentiating uterine versus extrauterine leiomyosarcomas (LMS). At best, these studies have shown only modest sensitivity and specificity for these markers in this context. In our own practice, we have noticed that retroperitoneal LMS, such as those arising in the wall of the inferior vena cava, frequently exhibit a remarkable resemblance not to uterine LMS, but rather to uterine leiomyomas (LM) with bizarre nuclei, formerly known as symplastic LM. This includes areas with bland nuclear cytology, punctuated by the presence of cells with large bizarre nuclei but a paradoxically low mitotic index. We refer to these areas in retroperitoneal LMS as “symplastic-like.” It has been our experience that these “symplastic-like” areas are frequently the predominant or exclusive component in small core biopsies of retroperitoneal LMS, even when the resection of these tumors reveals the presence of more conventional high-grade LMS morphology. In female patients, symplastic-like morphology in a smooth muscle tumor at an intra-abdominal site raises the possibility of iatrogenic dissemination of a uterine LM with bizarre nuclei from a prior myomectomy or morcellation procedure. We hypothesized that negative staining for ER and PR by IHC could effectively exclude a uterine origin, given the high sensitivity of these markers for all variants of uterine LM. After successfully using ER and PR IHC in our clinical practice on a few index cases, we decided to study a larger cohort of carefully selected cases to systematically determine the sensitivity and specificity of these markers in this very specific context. Confining our search to include only female patients, we identified 8 cases of retroperitoneal LMS that had been confirmed radiologically, intraoperatively and/or histologically to originate from a retroperitoneal source and 6 cases of uterine-based LM with bizarre nuclei, all diagnosed at our institution over an 8-year period. We tested only whole slides for ER and PR IHC. ER and PR were both completely negative in all 8 cases of retroperitoneal LMS and were both strongly expressed in all 6 cases of LM with bizarre nuclei. In conclusion, despite conflicting data in the literature regarding the utility of ER and PR in distinguishing uterine versus extrauterine smooth muscle tumors, we endorse the use of these markers for the specific distinction of retroperitoneal LMS with symplastic-like features from disseminated uterine LM with bizarre nuclei in female patients.

Malignant Glomus Tumor of the Uterus With Cyclin D1 Expression and CARMN::NOTCH2 Fusion

Glomus tumors of the female genital tract are rare, and to our knowledge, malignant glomus tumors (MGTs) of the female genital tract have not been previously reported. The diagnosis of MGTs is challenging, given their morphologic and immunophenotypic overlap with other common uterine mesenchymal tumors, especially in the absence of classic benign glomus tumor components. Here, we report a case involving a 34-year-old woman with uterine MGT that was positive for smooth muscle actin, h-caldesmon, cyclin D1, and synaptophysin, and negative for desmin. CARMN::NOTCH2 fusion was identified using hybrid capture-based next-generation sequencing. The presence of CARMN::NOTCH2 fusion combined with supportive immunohistochemical and morphologic features validated the diagnosis of MGT. The patient underwent 4 courses of chemotherapy with ifosfamide and pirarubicin. She had no evidence of tumor recurrence or metastasis at 20 months, as confirmed at the latest follow-up visit. The findings from this case highlight the morphologic and immunohistochemical features that are diagnostic of this rare uterine tumor. Furthermore, this report summarizes the morphologic criteria for malignancy and the key points for its differential diagnosis.

Coinactivation of the Switch/Sucrose Nonfermenting Complex SMARCA4/BRG1 and SMARCB1/INI1 in a Cervical Mixed Carcinoma: A Case Report

SMARCB1/SMARCA4-deficient malignancies of the female genital tract are rare entities, characterized by similar histologic features, such as sheet-like growth patterns and rhabdoid cells. Previous studies have shown mutually exclusive loss of SMARCA4/BRG1 and SMARCB1/INI1. Herein, we describe a unique cervical mixed carcinoma in a 77-year-old patient. The tumor consisted of 3 components, gastric-type adenocarcinoma, squamous carcinoma, and undifferentiated carcinoma. While the undifferentiated carcinoma was negtive for CK7, CK5/6 and p63, it was positive for pan-CK. DNA-based next-generation sequencing revealed a nonsense mutation in SMARCA4, copy number loss in SMARCB1, and a nonsense mutation in ARID1A. Different molecular alterations of the switch/sucrose nonfermenting complex subunits in the present case may provide further insights into the functions of the switch/sucrose nonfermenting complex in the progression of tumors.

A Case of CDKN2C/CIC Null Epithelioid Leiomyosarcoma With a Low-grade Component Indistinguishable From Leiomyoma

Numerous emerging molecularly defined subtypes of uterine leiomyosarcoma (LMS) have been described in recent years. Here we report our experience with a challenging case of the recently described CDKN2C/CIC null subtype of LMS – a LMS subtype that is frequently epithelioid in appearance, is wild-type for both TP53 and RB1 and may exhibit low-grade histology that falls short of LMS. The 48-year-old patient was initially diagnosed with an epithelioid leiomyoma with a component of intravenous leiomyomatosis. Recurrence occurred 5 years later with an extensive disease burden in the abdomen and pelvis. Upon review, the lesion in the hysterectomy specimen and the recurrent tumor had similar morphology. This included (1) focal epithelioid morphology meeting current diagnostic criteria for epithelioid LMS and (2) other areas with morphology indistinguishable from leiomyoma (LM), including conventional spindle cell LM, cellular LM, and LM with bizarre nuclei. Targeted next-generation molecular analysis performed on both the original tumor in the hysterectomy specimen and the tumor from the recurrence showed the same CDKN2C/CIC null profile. This case highlights the striking intratumoral heterogeneity that is possible in CDKN2C/CIC null LMS, including areas morphologically indistinguishable from LM. Clinicopathological findings in this case, including features that may assist in recognizing this challenging LMS subtype, are discussed. We underscore the importance of early diagnosis, which can facilitate appropriate adjuvant and/or maintenance therapy that may decrease the morbidity associated with extensive debulking surgery.

SATB2 Cytoplasmic Expression is Characteristic of a Subset of Ovarian Stromal Cells and Sex Cord Stromal Tumors

Special AT-rich sequence-binding protein 2 (SATB2) is a nuclear transcription factor that shows consistent nuclear staining in colorectal adenocarcinoma and osteosarcoma. Following the observation of cytoplasmic staining with this marker in luteinized ovarian stromal cells, we studied the expression of SATB2 in ovarian stromal cells, various types of follicular cysts, and sex cord-stromal tumors. Eighty-five cases were stained for SATB2. Ovarian hilar Leydig cells (n = 12), luteinized stromal cells (n = 10), corpora lutea (n = 4), luteinized follicular cysts (n = 4), and stromal hyperthecosis (n = 6) exhibited consistent, usually diffuse, granular cytoplasmic staining. In addition, Leydig cell tumors (n = 1) and steroid cell tumors (n = 4) showed diffuse cytoplasmic staining. SATB2 also exhibited cytoplasmic staining in most Sertoli-Leydig cell tumors (n = 16) and gynandroblastomas (n = 3) confined to the Leydig cell component. Adult granulosa cell tumors (n = 14), juvenile granulosa cell tumors (n = 3), sex cord tumors with annular tubules (n = 3), cellular fibromas (n = 3), sclerosing stromal tumors (n = 1), and thecomas (n = 1) were negative apart from cytoplasmic staining in associated luteinized stromal cells. SATB2 cytoplasmic staining has not been previously described in these lesions but is characteristic of a variety of ovarian stromal cells and sex cord-stromal tumors, in particular, those exhibiting luteinization or a Leydig or steroid cell component. SATB2 staining may be of value in identifying luteinized or Leydig cells when these are morphologically inconspicuous.

Entirely Exophytic HPV-associated Endocervical Adenocarcinoma: A Rare But Potentially Aggressive Neoplastic Phenomenon

A subset of human papillomavirus (HPV)-associated endocervical adenocarcinoma (EA) displays exclusively exophytic growth, with or without a classic villoglandular appearance. Given that increased depth and extent of destructive stromal invasion are associated with poorer prognosis for HPV-associated EA, it is believed that exclusively exophytic tumors are associated with a relatively indolent clinical course. There is, however, a paucity of data regarding the behavior of these neoplasms. We assembled a cohort of 73 patients with entirely resected cervix-confined HPV-associated EA treated with primary operative therapy. The tumors were classified based on architecture and presence/extent of stromal invasion, and histopathologic parameters, including the International Federation of Gynecology and Obstetrics (FIGO) 2018 substage and lymphovascular invasion (LVI). Clinical outcomes including local recurrence, metastasis, and death were evaluated. Of 73 tumors, 4 (6%) demonstrated exclusively exophytic growth (0.4–2.2 cm in maximal dimension). All lacked LVI as well as nodal involvement. None of the 4 patients with exclusively exophytic tumors received adjuvant therapy. Two of the 4 (50%), however, experienced recurrence and both patients eventually died of causes related to EA. Of the remaining 69 cases with a component of nonexophytic growth, <6% of patients experienced tumor recurrence. Our study has found that, in at least a subset of cases, exclusively exophytic HPV-associated EA is associated with adverse outcomes. Additional studies are needed to substantiate these findings and to identify additional features (pathologic, molecular, etc.) that may aid in identifying those patients who could benefit from more aggressive treatment.

Sclerosis in Metastatic Uterine Tumor Resembling Ovarian Sex Cord Tumor: Diagnostic Dilemma Presented by Unusual Morphology

Uterine tumors resembling ovarian sex cord tumors (UTROSCT) are rare neoplasms that typically follow a benign course. However, metastasis occurs in rare cases and features associated with poor outcomes are only recently being described. These include: size >5 cm, at least moderate cytologic atypia, >3 mitosis per 10 high-powered fields, infiltrative borders, necrosis, GREB1 rearrangements, ESR1 rearrangements, and NCOA2/3 fusions. To our knowledge, prominent sclerosis has not been described in UTROSCT, nor has it been associated with an increased risk of metastasis. We present the case of a 51-yr-old woman with UTROSCT with corded/trabecular growth and sclerosis. The presence of sclerosis resulted in the misdiagnosis of her uterine tumor as leiomyoma and her lung metastasis as sclerosing epithelioid fibrosarcoma. The correct diagnosis of UTROSCT with lung metastasis was reached upon a morphologic comparison of the primary and metastatic tumors and the performance of a broad panel of immunohistochemical stains revealing the tumor to be CD99, CD56, ER, and inhibin positive and negative for rearrangements in 138 targeted genes, including genes commonly described as rearranged in endometrial stromal sarcomas, Ewing sarcoma and sclerosing epithelioid fibrosarcoma. The panel did not include GREB1 or ESR or NCOA3, but NCOA1/2 rearrangements were not detected. Our case highlights the diagnostic dilemma introduced by the presence of sclerosis in UTROSCT. We suspect prominent sclerosis may be another feature predictive of malignant potential in UTROSCT.

Clinicopathologic and Genomic Features of Invasive Stratified Mucin-producing Carcinoma of the Uterine Cervix Coexisting With High-grade Squamous Intraepithelial Lesion

Invasive stratified mucin-producing carcinoma (ISMC) is a specific type of adenocarcinoma of the cervix, which is associated with human papillomavirus infection and often coexists with other types of carcinomas. However, given its rarity, understanding of this disease remains insufficient. We present a unique case of ISMC of the cervix coexisting with a high-grade squamous intraepithelial lesion (HSIL). In addition to histologic and immunohistochemical feature observation, genomic profiling of the 2 lesions was performed. Histologically, the ISMC and HSIL lesions were independent of each other. Aside from the typical morphology, various architectural features of ISMC were observed. Immunohistochemically, the ISMC and HSIL lesions were strongly and diffusely positive for p16 and exhibited high Ki-67 expression. The ISMC lesion was also positive for CK7, MUC5AC, and MUC6, while it was negative for PAX-8. The HSIL lesion was positive for CK5/6 and p40. The combined positive score of PD-L1 was 55. The other markers were all negative in both lesions, and the p53 was wild-type. Next-generation sequencing analysis revealed multiple gene mutations in the ISMC and HSIL lesions. A total of 88 gene mutations were identified in the ISMC lesion, while 20 gene mutations were identified in the HSIL lesion. Three mutations (ERBB2, histidine decarboxylase gene [HDC], and BSN) were detected in the ISMC and HSIL lesions. Both lesions had a low tumor mutation burden and microsatellite-stable status. No copy number-associated variants or structural variations were identified in either lesion. These results suggest that patients with ISMC may benefit from PD-L1 immunotherapy and targeted therapy.

Whole-exome Sequence Analysis of Gastric-type Adenocarcinoma of the Uterine Cervix and Adjacent Lobular Endocervical Glandular Hyperplasia in the Same Case

Lobular endocervical glandular hyperplasia (LEGH) may be a precursor lesion of gastric-type adenocarcinoma of the uterine cervix (GAS). However, the genetic mechanisms underlying its carcinogenesis remain unclear. To elucidate the oncogenic process from LEGH to GAS, we compared gene mutations in early-stage GAS and adjacent LEGH in the same case. Fresh-frozen tissue sections were obtained from a patient with Stage IB3 GAS and adjacent LEGH who had undergone hysterectomy. Using laser microdissection, we harvested the LEGH and GAS portions separately from these sections and extracted the genomic DNA. Somatic variant analysis using whole-exome sequencing used DNA from the normal myometrium as a reference sequence. Somatic variants involving amino acid substitutions were detected in 61 and 125 locations in LEGH and GAS, respectively. Seven variants were common in both lesions, of which the pathogenic variant was GNAS only (c.2531G>A, p.R844H), a mutation frequently reported in pancreatic and colorectal cancers. LEGH had no other pathogenic variants; another pathogenic variant in GAS was found only at the same amino acid site as GNAS (c.2530C>T, p.R844C). In the present case, LEGH and GAS shared the same pathogenic variant of GNAS, indicating that both lesions had a common origin. Furthermore, the current results showed that the second GNAS variant is associated with the progression of LEGH to GAS. Further studies are required to elucidate GAS’s pathogenesis and biological characteristics.

Improved Risk Prediction in Human Papillomavirus–Associated Endocervical Adenocarcinoma Through Assessment of Binary Silva Pattern-based Classification: An International Multicenter Retrospective Observational Study Led by the International Society of Gynecological Pathologists (ISGyP)

Endocervical adenocarcinomas (EACs) are a group of malignant neoplasms associated with diverse pathogenesis, morphology, and clinical behavior. As a component of the International Society of Gynecological Pathologists International Endocervical Adenocarcinoma Project, a large international retrospective cohort of EACs was generated in an effort to study potential clinicopathological features with prognostic significance that may guide treatment in these patients. In this study, we endeavored to develop a robust human papillomavirus (HPV)–associated EAC prognostic model for surgically treated International Federation of Gynecology and Obstetrics (FIGO) stage IA2 to IB3 adenocarcinomas incorporating patient age, lymphovascular space invasion (LVSI) status, FIGO stage, and pattern of invasion according to the Silva system (traditionally a 3-tier system). Recently, a 2-tier/binary Silva pattern of invasion system has been proposed whereby adenocarcinomas are classified into low-risk (pattern A/pattern B without LVSI) and high-risk (pattern B with LVSI/pattern C) categories. Our cohort comprised 792 patients with HPV-associated EAC. Multivariate analysis showed that a binary Silva pattern of invasion classification was associated with recurrence-free and disease-specific survival (P < 0.05) whereas FIGO 2018 stage I substages were not. Evaluation of the current 3-tiered system showed that disease-specific survival for those patients with pattern B tumors did not significantly differ from that for those patients with pattern C tumors, in contrast to that for those patients with pattern A tumors. These findings underscore the need for prospective studies to further investigate the prognostic significance of stage I HPV-associated EAC substaging and the inclusion of the binary Silva pattern of invasion classification (which includes LVSI status) as a component of treatment recommendations.

Superficial and Invasive Spread of High-grade Squamous Intraepithelial Lesion and Squamous Cell Carcinoma: A Case Report

We present a case of extensive spread of high-grade squamous intraepithelial lesion (HSIL)/cervical intraepithelial neoplasia grade 3 (CIN3) with foci of invasive squamous cell carcinoma (SCC) in a premenopausal woman. Superficial spread of CIN3 and cervical SCC to the endometrium and/or fallopian tubes is rare, especially in countries with cervical cancer screening programs. Our case occurred during the COVID-19 pandemic, which may have been a major contributing factor to delayed detection and, consequently extensive spread.

A Population-based Study Investigating the Incidence of Human Papillomavirus–Associated and Human Papillomavirus–Independent Cervical Adenocarcinomas

Cervical adenocarcinomas are now classified as human papillomavirus (HPV)-associated and HPV-independent types with the former being more common. However, population-based studies regarding the relative incidences of the 2 types are few. This study investigates the incidence of cervical adenocarcinomas in Northern Ireland (a country with a relatively stable population of ~1.8 million) over a recent 9-year period (2015–2023). Overall, there were 146 primary cervical adenocarcinomas, 130 HPV-associated (89%) and 16 HPV-independent (11%). The median age was 43 years (range: 24–82) for HPV-associated and 62.5 years (range: 31–84) for HPV-independent neoplasms; this was statistically significant (P < 0.001). The calculated age-adjusted incidence of the patients with HPV-associated and HPV-independent neoplasms was 1.68 and 0.20 per 100,000 person-years, respectively. The HPV-independent neoplasms were more often advanced stage at diagnosis; 97 of 130 (75.4%) of the HPV-associated cases were diagnosed at Stage I compared with 5 of 16 (31.3%) of the HPV-independent cases. The HPV-independent neoplasms were mostly gastric-type (56.3%) with smaller numbers of clear cells and mesonephric. Despite the relatively short follow-up, the mortality of patients with HPV-independent adenocarcinomas was significantly higher than patients with HPV-associated neoplasms (56.3% vs 5.4%) with a median survival of just over a year (13.2 mo) in the former for those who died.

Mixed Gestational Trophoblastic Tumors—Challenging Clinicopathological Presentations

Mixed gestational trophoblastic tumors are exceptionally rare and have variable clinicopathological presentations. We report 3 such tumors with different combinations of choriocarcinoma (CC), placental site trophoblastic tumor (PSTT), and epithelioid trophoblastic tumor (ETT). The patients’ age ranged from 38 to 44 years. Mixed trophoblastic tumor was not considered at the initial diagnosis and all 3 tumors were proven of gestational origin by DNA genotyping. Patient #1 presented with serum human chorionic gonadotropin (hCG) of 97 mIU/mL and a 5.6-cm cervical mass that was initially interpreted as PSTT on biopsy. Hysterectomy revealed a mixed PSTT (60%) and ETT (40%) with extrauterine metastases of only the ETT component. The tumor recurred 15 months after a multiagent chemotherapy and was tested positive for programmed death-ligand 1. The patient received immune checkpoint inhibitor therapy and remained disease-free after 24 months. Patient #2 presented with vaginal bleeding and serum hCG of 46,458 mIU/mL. An endometrial biopsy was interpreted as CC. Recurrence developed in the uterus and lung after methotrexate-based chemotherapy. A mixed CC and ETT were eventually diagnosed upon consultation review. Patient #3 presented with a complete hydatidiform mole and serum hCG of 744,828 mIU/mL. Three months after methotrexate, followed by actinomycin D therapy, a uterine mass was found. Hysterectomy revealed a mixed CC and PSTT. In conclusion, the rarity, elusive presentation, and wide range of histology make the diagnosis of mixed trophoblastic tumors highly challenging. The clinical management and prognosis are dictated by each component of the tumor. CC component must be considered when the patient presents with a high serum hCG level.

Human Papilloma Virus–Independent/p53abnormal Keratinizing Squamous Cell Carcinoma of the Uterine Cervix Associated With Uterine Prolapse

Knowledge about the morphologic and molecular characteristics of cervical squamous cell carcinomas (CSCCs) associated with uterine prolapse is very limited. Detailed histopathological and immunohistochemical (p16, p53, and cytokeratin 17), as well as molecular evaluation for human papillomavirus (HPV)-DNA and p53-mutational analyses in 4 consecutive CSCCs associated with uterine prolapse with definition of a hitherto not well-described HPV-independent/p53abnormal precursor lesion (HPV-independent cervical intraepithelial neoplasia [CIN; differentiated CIN]) and molecular tumorigenetic pathway. Cases diagnosed within 7 years with a mean age of 75 (range: 69–83) years and a mean tumor size of 7.3 cm (range: 5.2–9.4 cm). All patients presented with locally advanced disease, and 1 woman died of the disease within 4, and another within 14 months of follow-up. All CSCCs and their adjacent precursor lesions were negative for p16, with aberrant p53-expression and diffuse and strong staining for cytokeratin 17. Both the CSCCs and their precursors were negative for HPV-DNA but harbored a TP53 mutation. The precursor lesions were characterized by epithelial thickening with superficial keratinization, and the presence of basal and parabasal keratinocytes with mitotic figures beyond the basal layer, thus showing features similar to those seen in differentiated types of vulvar intraepithelial lesions (vulvar intraepithelial neoplasia [VIN] syn. HPV-independent/p53abn VIN), suggesting the terminology of differentiated CIN or HPV-independent/p53abn CIN. An HPV-independent pathogenetic pathway with a p53-alteration was identified for these cases. CSCC associated with uterine prolapse represents HPV-independent tumors harboring a TP53 mutation. For the first time, a precursor lesion of HPV-independent CSCC of the uterine cervix is described with a differentiated VIN–like morphology, and a separate tumorigenic pathway defined.

Stathmin is an Independent Prognostic Marker of Poor Outcome in Uterine Leiomyosarcoma

The objective of this study was to analyze the expression and prognostic role of cancer-associated proteins in uterine leiomyosarcoma (uLMS). p53, DAXX, ATRX, HMGA2, IMP3, Stathmin, and phospho-Stathmin (p-Stathmin) protein expression by immunohistochemistry was analyzed in tissue microarrays from 244 uLMS. Expression was assessed for association with clinicopathologic parameters in 173 patients with available data. Tissue microarrays were informative in 230 cases. p53 was aberrant in 44% of tumors. DAXX, ATRX, HMGA2, IMP3, and Stathmin were expressed in 90%, 55%, 40%, 33%, and 97% uLMS, respectively. Cytoplasmic and nuclear p-Stathmin staining was seen in 77% and 68% of tumors, respectively. Stathmin expression was significantly related to higher mitotic count (P < 0.001), a higher degree of atypia (P = 0.006), and vascular invasion (P = 0.016), whereas p-Stathmin expression was significantly related to advanced stage (P < 0.001), higher mitotic count (P < 0.001), and vascular invasion (P = 0.001). In univariate survival analysis for 165 patients with informative tissue microarrays, aberrant p53 (P = 0.026) and higher IMP3 (P = 0.024), Stathmin (P < 0.001), cytoplasmic p-Stathmin (P < 0.001), and nuclear p-Stathmin (P < 0.001) expression was associated with poor disease-specific survival. Clinicopathologic parameters significantly related to poor disease-specific survival were older age (P = 0.006), extrauterine disease at diagnosis (International Federation of Gynecology and Obstetrics (FIGO) stage ≥2; P < 0.001), high mitotic count (P = 0.02), and grade 2 to 3 atypia (P = 0.017). In multivariate analysis, age (P = 0.002), FIGO stage (P < 0.001), and Stathmin expression (P < 0.001) were independent prognosticators. Stathmin was the only prognosticator in a multivariate analysis limited to patients with FIGO stage I disease (P = 0.013). In conclusion, Stathmin expression is strongly associated with poor survival in uLMS and may be a new prognostic marker in this malignancy.

Wilms Tumor of the Ovary: Review of the Literature and Report of 2 Cases

Primary extrarenal Wilms tumor of the gynecologic tract is extremely rare with scattered case reports occurring in the ovary, uterine corpus and cervix. Only 9 cases of primary ovarian Wilms tumor have been reported to date. Here, we provide an extensive literature review and describe 2 patients with ovarian Wilms tumor: a 36-yr-old female (patient 1) and a 16-yr-old female (patient 2), both presenting with abdominal pain and suspected ovarian torsion. They were each found to have unilateral ovarian masses measuring >15 cm in size which were removed by unilateral salpingo-oophorectomy. Microscopically, the tumors exhibited the typical triphasic histology of Wilms tumor. In addition, the tumor from patient 1 contained elements of mature cystic teratoma, while an extensive rhabdomyosarcomatous component was identified in patient 2. Both tumors were diffusely and strongly positive for WT1 with variable staining for other biomarkers. The cases were diagnostically challenging and referred to our center for an expert opinion. Teratoid Wilms tumor in patient 1 is the second reported case of ovarian Wilms tumor arising in association with teratoma. Recognition of primary ovarian Wilms tumor requires a high index of suspicion and exclusion of other entities based on tumor morphology and immunohistochemical studies.

Neuroendocrine Marker Expression in Primary Non-neuroendocrine Epithelial Tumors of the Ovary: A Study of 551 Cases

Expression of neuroendocrine (NE) markers in primary ovarian non-NE epithelial tumors has rarely been evaluated. The aim of our study was to evaluate the expression of the most widely used NE markers in these neoplasms and to determine any prognostic significance of NE marker expression. The cohort consisted of 551 primary ovarian tumors, including serous borderline tumors, low-grade serous carcinomas, high-grade serous carcinomas (HGSC), clear cell carcinomas, endometroid carcinomas, mucinous borderline tumors, and mucinous carcinomas. Immunohistochemical analysis was performed using antibodies against INSM1, synaptophysin, chromogranin, and CD56 on tissue microarray. Positivity for INSM1, synaptophysin, chromogranin, and CD56 was most frequently observed in mucinous tumors (48.7%, 26.0%, 41.5%, and 100%, respectively). The positivity for these NE markers was mostly restricted to nonmucinous elements distributed throughout the tumor. The mucinous borderline tumor and mucinous carcinomas groups had similar proportions of positivity (mucinous borderline tumor: 53%, mucinous carcinomas: 39%). In the other tumor types, except for HGSC, there was only focal expression (5%–10%) or negativity for NE markers. HGSC showed high CD56 expression (in 26% of cases). Survival analysis was only performed for CD56 in HGSC as this was the only group with sufficient positive cases, and it showed no prognostic significance. Except for mucinous tumors, expression of NE markers in non-NE ovarian epithelial tumors is low. CD56 expression in HGSC occurs frequently but is without diagnostic or prognostic value.

High-Risk Human Papillomavirus–Associated Mixed Intestinal-Type Mucinous Adenocarcinoma and Low-grade Neuroendocrine Tumor of the Uterine Cervix: Report of a Case Harboring Shared ARID1A and SMAD4 Mutations Between Morphologically Distinct Components

Risk Factors Affecting Clinical Outcomes of Low-risk Early-stage Human Papillomavirus–Associated Endocervical Adenocarcinoma Treated by Surgery Alone: Application of Silva Pattern

This study aimed to report the clinical outcomes and risk factors for survival of patients with low-risk early-stage human papillomavirus–associated (HPVA) endocervical adenocarcinoma (EAC) treated with surgery alone. This retrospective study obtained the clinicopathological data of patients with early-stage HPVA EAC who underwent surgery between 2012 and 2018. The Silva pattern of invasion was determined by reviewing pathology slides. Locoregional recurrence-free survival (RFS), RFS, and overall survival were calculated, and the risk factors for survival were analyzed. One hundred seventeen patients with a median follow-up of 5.2 years (0.5–9.7 yr) were included. The most common histologic type was usual (94/117, 80.3%). The Silva pattern was A in 79 patients (67.5%), B in 30 (25.6%), and C in 8 (6.8%). The 5-year locoregional RFS, RFS, and overall survival rates were 92.4%, 87.8%, and 97.2%, respectively. The presence of intermediate-risk factors and Silva pattern C were significantly associated with worse survival. Based on these findings, patients were categorized into 2 groups: Group 1 (Silva pattern A or Silva pattern B without intermediate-risk factors) and Group 2 (Silva pattern B with intermediate-risk factors or Silva pattern C ). Group 2 showed significantly worse outcomes than Group 1, including the 5-year locoregional RFS (98.6% vs 68.0%), RFS (96.4% vs 54.6%), and overall survival (100.0% vs 86.5%). In conclusion, surgery alone for early-stage HPVA EAC resulted in favorable outcomes. Consideration of the Silva pattern, in addition to well-known risk factors, could help in precise risk group stratification of low-risk, early-stage HPVA EAC.

PD-L1 Expression and Silva Invasion Pattern in Villoglandular Adenocarcinoma of the Uterine Cervix

Villoglandular adenocarcinoma (VGA) of the uterine cervix is a rare subtype of endocervical adenocarcinoma in young women. Between 2007 and 2020, all women with endocervical adenocarcinoma were retrospectively reviewed to find patients with VGA. Eight patients in whom pure VGA had been diagnosed were included. The mean age at initial diagnosis was 36.3 years (range 24–46). After surgical treatment, patients were followed up for 59 months (range 16–150). To date, all patients are alive with no evidence of disease. Neither lymph node involvement nor lymphovascular invasion was found. Furthermore, we examined the samples with a focus on morphological invasion pattern (Silva), stromal tumor-infiltrating lymphocytes (sTILs), and immunohistochemical programmed death ligand-1 (PD-L1) expression. PD-L1 expression was observed in 7/8 using the combined positive score (cutoff≥1%), 1/8 of VGAs using the tumor proportion score (cutoff≥1%), and 7/8 using the immune cell (cutoff≥1%). Using combined positive score and immune cell, PD-L1 expression was seen in 7/8 of pattern B and C tumors, with significantly higher expression in tumors with destructive-type patterns (P<0.05, A vs. B+C). Using tumor proportion score, no significant difference in PD-L1 expression was seen between VGAs with different invasion patterns. VGAs demonstrated twice higher sTILs in tumors with destructive-type invasion patterns. Our observations suggest that PD-L1 expression, tumor invasion patterns, and sTILs do not correlate with the excellent prognosis of pure VGA.

SMARCB1 (INI1) Deficient Tumours of the Uterine Cervix: Report of Two Cases, Including One Associated With an NTRK Fusion

Pathogenic variants (mutations) and other molecular events involving subunits of the SWItch/Sucrose Non-Fermentable chromatin remodelling complex are common in a wide variety of malignancies. Many of these neoplasms are characterized by undifferentiated morphology. They arise at a variety of sites in the female genital tract but have rarely been reported in the uterine cervix. We report 2 primary cervical neoplasms arising in young women (ages 28 and 29 yr) exhibiting loss of nuclear immunoreactivity with SMARCB1 (INI1). In one case, which had a mixture of epithelioid and spindle cells, molecular studies revealed no SMARCB1 pathogenic variant, but showed a SPECCL1::NTRK 3 fusion, in keeping with an NTRK fusion sarcoma. The second case exhibited rhabdoid morphology and molecular testing confirmed a SMARCB1 pathogenic variant (c.425 T>G:p.(Leu142Ter) which, interpreted in conjunction with the morphology and immunohistochemistry, resulted in classification as a proximal-type epithelioid sarcoma. To our knowledge, this is the first reported cervical neoplasm exhibiting a SMARCB1 pathogenic variant and the first NTRK fusion sarcoma showing SMARCB1 protein loss. We discuss the diagnostic challenges and complexities of the molecular findings.

Diffuse Pediatric-type High-grade Glioma Arising in an Ovarian Mature Cystic Teratoma

Immature neuroectodermal tissue can be found in the ovary as part of an immature teratoma or as part of a teratoma with malignant neuroectodermal transformation. Such lesions may closely resemble central nervous system tumors, but their biologic similarity is unclear. We describe an 18-yr-old female who presented with abdominal pain caused by an ovarian mass with widespread metastases. Histology showed a primitive, high-grade tumor arising in the background of a mature teratoma. The tumor was SOX10 positive, with focal expression of GFAP, S100, NSE, and synaptophysin. Molecular analysis demonstrated co-amplification of PDGFRA and KIT, alterations common in high-grade gliomas. By whole-genome methylation profiling, it clustered into the “diffuse pediatric-type high-grade glioma, RTK1 subtype, subclass c” group. Despite progressing through 2 lines of chemotherapy with widespread metastatic disease, she achieved an excellent response to chemotherapy directed toward aggressive germ cell tumors. This case emphasizes the importance of immunohistochemical, genomic, and epigenetic analyses to accurately classify these exceedingly rare tumors and determine the optimal therapy.

Enteric Type Bartholin Gland Adenocarcinoma: An Unusual Variant of a Rare Neoplasm

Vulval cancer is rare. With Bartholin gland carcinomas representing <5% of all vulval carcinomas they present both diagnostic and management challenges. There are a small number of cases in the literature describing Bartholin gland carcinomas with unusual histology which necessitates the need to explore the possibility of metastases from elsewhere. We present a case of a 55-yr-old woman presenting with a vulval lesion within the Bartholin gland. Morphology demonstrated enteric type adenocarcinoma and the immunohistochemistry profile was positive for CK7, CK20, CDX2, CEA, and CA19-9. There was no evidence of an alternative primary cancer and the tumor was excised with negative regional sentinel node assessment. Genotyping showed no detectable mutations in KRAS, BRAF or NRAS suggesting a possible future role for anti-EGFR therapy.

Interobserver Reproducibility in Assessing Eosinophilic Cells in Ovarian Serous Borderline Tumors to Predict BRAF Mutational Status

Ovarian serous borderline tumors (SBTs) harboring the BRAF V600E mutation are associated with decreased risk of progression to low-grade serous carcinoma, and often prominently feature tumor cells with abundant eosinophilic cytoplasm. Since eosinophilic cells (ECs) may be a marker of the underlying genetic driver, we proposed morphologic criteria and evaluated the interobserver reproducibility for assessing this histologic feature. Following the completion of an online training module, representative tumor slides from 40 SBTs (BRAF V600E-mutated, n=18, BRAF-wildtype, n=22) were independently reviewed by 5 pathologists. For each case, reviewers provided a semiquantitative assessment of the extent of ECs (0: absent, 1: <10%, 2: 10%–50%, or 3: >50%, of tumor area). Interobserver reproducibility for estimating the extent of ECs was moderate (κ=0.41). Applying a cut-off score of ≥2, the median sensitivity and specificity for predicting BRAF V600E mutation were 67% and 95%, respectively. With a cut-off score of ≥1, median sensitivity and specificity were 100% and 82%, respectively. Morphologic mimics of ECs, including tumor cells with tufting or hobnail change and detached cell clusters in micropapillary SBTs, were possible contributing factors for discordant interobserver interpretations. BRAF V600E immunohistochemistry showed diffuse staining in BRAF-mutated tumors, including those with few ECs. In conclusion, the finding of extensive ECs in SBT is highly specific for BRAF V600E mutation. However, in some BRAF-mutated SBTs, ECs may be focal and/or difficult to distinguish from other tumor cells with overlapping cytologic features. The morphologic finding of definitive ECs, even when scarce, should therefore prompt consideration for BRAF V600E mutation testing.

Somatic BAP1 Loss in Ovarian Serous Borderline Tumor and Recurrent Low-grade Serous Carcinoma From a Germline BAP1 Mutation Carrier

Intratumoral Heterogeneity Accounts for Apparent Progression of Noninvasive Serous Tumors to Invasive Low-grade Serous Carcinoma: A Study of 30 Low-grade Serous Tumors of the Ovary in 18 Patients With Peritoneal Carcinomatosis

Noninvasive ovarian low-grade serous tumors [atypical proliferative serous tumor (APST)/serous borderline tumor] appear to progress to invasive low-grade serous carcinoma (LGSC) at a low but regular rate. The underlying biology of this phenomenon is unknown. We studied 18 patients with 30 ovarian tumors (12 bilateral), including APST, noninvasive LGSC and invasive LGSC, who also had low-grade serous carcinomatosis. Tumors were evaluated for microinvasion (usual eosinophilic cell type), microinvasive carcinoma (<5 mm invasion of micropapillary nests), and overt carcinoma (≥5 mm invasion of micropapillary nests). Tumors were evaluated based on the original numerical order of sections under the hypothetical scenarios in which sampling was stopped at 1 section/cm and 2 sections/cm. Sampling based on 1 section/cm of greatest tumor dimension identified invasion of any type in 21 tumors (70%). Among these 21 tumors, 10 had microinvasive carcinoma, and 11 overt carcinoma. Sampling based on 2 sections/cm identified microinvasive carcinoma in 9 tumors and overt carcinoma in 14 tumors. With increased sampling from 1 to 2 sections/cm, the diagnosis in 3 tumors would have changed from microinvasive carcinoma to overt carcinoma, and in an additional 2 tumors from APST to APST with microinvasive carcinoma. Sampling based on >2 sections/cm changed the diagnosis in 1 additional case of APST with microinvasive carcinoma to overt carcinoma. These findings support that undetected (unsampled) occult invasion in the primary ovarian tumors is a likely explanation for some cases of apparent progression of noninvasive low-grade serous ovarian tumors to invasive LGSC. To minimize undetected occult invasion, consideration of sampling noninvasive low-grade ovarian serous tumors with at least 2 sections/cm of maximum tumor diameter may be warranted. The eosinophilic cell type of microinvasion, or microinvasive carcinoma, regardless of size, should prompt further sampling to identify overt carcinoma. The eosinophilic type of microinvasion was never seen alone in this cohort and by itself may be biologically insignificant.

Adult Granulosa Cell Tumor With Sarcomatous Transformation: A Case Study With Emphasis on Molecular Alterations

Adult granulosa cells tumors (AGCTs) are typically low-grade indolent tumors. On rare occasions, they undergo high-grade/sarcomatous transformation and behave aggressively. This transformation is postulated to occur as the result of acquired genetic alterations, some of which may be eligible for targeted therapy. Here we report a rare case of AGCT with sarcomatous transformation that harbored distinct molecular alterations from those typically seen with AGCTs supporting a molecularly driven approach to these malignancies. The patient is a 56-yr-old G3P3 woman with a history of multiple recurrences of ovarian AGCT for which the first diagnosis was made at the age of 25 when she was evaluated for infertility. The ovarian tumor displayed typical features of AGCT with low-grade, bland morphology. The first extraovarian spread of tumor involving the cul-de-sac was reported at the age of 39. After that, recurrences occurred every 2 to 3 yr with involvement of multiple anatomic sites and repeated surgical resections. At the age of 55 she developed a symptomatic recurrence in the pelvis and underwent resection of an isolated lesion (specimen 1) to no gross residual disease. Within 4 wk of resection she developed significant pelvic pain and imaging showed recurrence of the mass. Therefore, in 5 mo after the initial resection she underwent repeat excision of the lesion (specimen 2) and associated bowel. The sections from specimen 1 showed a biphasic morphology: a low-grade component with morphology and immunophenotype consistent with a typical AGCT and a high-grade spindle cell component with features consistent with a high-grade sarcoma. Specimen 2 featured a pure high-grade sarcoma characterized by coagulative tumor cell necrosis, readily recognizable mitoses, highly atypical cells with vesicular nuclei and prominent nucleoli. SF-1 positivity and the presence of FOXL2 C134W mutation in the sarcomatous component support the notion of transformation of typical AGCT. While detected TERT promoter C228T mutation may play a role in this process, we further identified genetic alterations affecting PI3K/AKT/mTOR pathway, including mutations in PIK3CA, PIK3R1, AKT1, and NF2, which may also contribute to tumor progression/transformation. These findings provide rationale for molecular/pathway-based targeted therapy for patients with advanced AGCT.

An Unusual Enteric Yolk Sac Tumor: First Report of an Ovarian Germ Cell Tumor Associated With a Germline Pathogenic Variant in DICER1

A variety of unusual tumors are associated with both germline and somatic DICER1 pathogenic variants (PVs), including, in the female genital tract, embryonal rhabdomyosarcoma at various sites and ovarian Sertoli-Leydig cell tumor. There have been occasional reported cases of ovarian germ cell tumors [mainly yolk sac tumor (YST)] harboring DICER1 PVs but, as far as we are aware, none of these has been proven to have a germline provenance. We report an unusual enteric variant of ovarian YST in a 28-yr-old woman associated with a germline PV c.901C>T (p.Gln301Ter) in exon 7 of DICER1, accompanied by a somatic (YST-only) hotspot mutation: c.5437G>A, p.E1813K. To our knowledge, this is the first report of an ovarian germ cell tumor associated with a germline DICER1 PV. We review other reported cases of ovarian germ cell tumor with DICER1 PVs and discuss the differential diagnosis of this unusual variant of YST which was originally diagnosed as a mucinous adenocarcinoma.

Cystic Ovarian Mucinous Carcinoma With Carcinosarcomatous Mural Nodules: An Uncommon Entity

Mural nodules in ovarian mucinous cystic tumors are uncommon, with only 80 cases reported over the last 30 yr. The literature describes only 5 cases of carcinosarcomatous mural nodules with mucinous ovarian neoplasm. We compared and summarized the literature related to mural nodules in mucinous ovarian tumors to elaborate on the clinical and histomorphologic features. A 21-yr-old woman presented with 2 mo history of abdominal distension. Physical examination showed a palpable pelvic mass. Radiologic investigation showed a 31×18.6×25 cm large right ovarian cyst. Few nodular solid masses were also seen, the largest mass measured 3.5×3.1 cm. On histomorphology and immunohistochemistry, it was a mucinous ovarian carcinoma with carcinosarcomatous mural nodules. Carcinosarcomatous mural nodules with ovarian mucinous neoplasm affects younger females. It presents at an early stage and does not carry an adverse prognosis.

Prevalence of Occult Ovarian Cancer and Metastatic Breast Cancer in Ovarian Ablation Specimens of Patients With Hormone Receptor-Positive Breast Cancer: Implications for Tissue Sampling Strategies, Early Ovarian Cancer Detection and Resource Utilization

Bilateral oophorectomy is one method of hormone suppression for premenopausal patients with hormone receptor-positive breast cancer. Such specimens could, in theory, harbor occult early ovarian cancer and/or metastatic breast cancer but guidelines for tissue sampling for pathologic examination remain to be addressed. Therefore, we evaluated oophorectomy specimens from 166 patients who underwent ovarian ablation for hormone receptor-positive breast cancer. Results of germline genetic testing were documented by the surgeon in only 31.3% of the pathology specimen requisition forms, whereas that information was available for 81.3% of patients elsewhere in the electronic medical records. All but 5.2% tested negative for a hereditary ovarian cancer gene pathogenic variant before oophorectomy. Complete tissue sampling was performed in 77.1% of the cases and representative sampling in the remainder. No cases of ovarian cancer were observed. Ovarian metastasis of breast cancer was identified in 9.6% of patients, all of whom were already known to have advanced-stage disease. The number of tissue cassettes per ovary required for complete tissue submission was on average three times higher than that for representative tissue sampling (P < 0.01) and ranged up to 20 cassettes per ovary when multiple follicle cysts were present. We propose that guidelines for tissue sampling in this context be defined by a combination of hereditary risk and macroscopic examination; representative sampling is reasonable for macroscopically normal ovaries in hormone receptor-positive breast cancer patients whose germline genetic testing is negative. Positive genetic test results merit complete tissue submission even if macroscopically normal. This strategy balances the goals of early ovarian cancer detection and optimal resource utilization. However, it depends on clear documentation of genetic test results. Our study demonstrates that many opportunities remain to close gaps in the communication of genetic test results by clinicians submitting oophorectomy specimens for pathologic evaluation.

Evidence for a Novel Endometrioid Carcinogenic Sequence in the Fallopian Tube With Unique Beta-Catenin Expression

Epithelial proliferations in the fallopian tube have been characterized by some as stem cell outgrowths (SCOUTs) and divided into type I and type II. Type II SCOUTs exhibit diffuse cellular beta-catenin nuclear staining (β-catenin+), implying a CTNNB1 mutation. SCOUTs are more common in perimenopausal and postmenopausal women and are associated with ovarian cancer but have not been linked directly to malignancy. We analyzed type II SCOUTs in various gynecologic conditions, and searched for endometrioid atypical hyperplasias (tubal endometrioid intraepithelial neoplasia) or adenocarcinomas in the tube. β-catenin+ SCOUT frequency in cases of neoplasia was 66.7% per case and 30.7% per nonfimbrial cross-section for uterine endometrioid carcinomas versus 25% and 13.3% for controls, respectively (P=0.02 and 0.09). Multiple (3 or more) β-catenin+ SCOUTs in a single section were uncommon; 6 of 9 were associated with a carcinoma or proliferative lesion in the endometrium. Tubal endometrioid intraepithelial neoplasia/atypical hyperplasia displayed complex growth, including focal cribriform growth patterns and squamous morules. Two cases of type II SCOUTs associated with tubal endometrioid intraepithelial neoplasia/atypical hyperplasia and/or adenocarcinomas in the fallopian tube were identified, both of which coexisted with a separate endometrioid adenocarcinoma, one with bilateral ovarian endometrioid adenocarcinomas. Both benign and neoplastic tubal lesions were β-catenin+. This report is the first to link components of a unique β-catenin+ endometrioid carcinogenic sequence in the fallopian tube. It further emphasizes the multifocal nature of endometrioid neoplasia in the female genital tract and poses questions regarding the frequency and biologic underpinnings of β-catenin+ proliferations in the oviduct.

Clinicopathologic Evaluation of CTNNB1 Mutations in High-Intermediate Risk Endometrial Endometrioid Carcinoma

CTNNB1 mutations convey increased risk of recurrence in low-risk endometrial endometrioid carcinoma (EEC). Results from previous high-intermediate risk (HIR) cohorts are mixed. The aims of this study were to correlate CTNNB1 mutational status with clinical outcomes and to evaluate the relationship between CTNNB1 mutations and the 4 prognostic subgroups defined by The Cancer Genome Atlas in HIR EEC. CTNNB1 mutational status was determined by Sanger sequencing of exon 3 of the CTNNB1 gene. Mismatch repair, POLE, p53, and L1 cell-adhesion molecule (L1CAM) status were also evaluated. Descriptive statistics and survival analyses were performed. Eighty-eight cases of HIR EEC were identified, of which 22 (25%) were CTNNB1 mutant (CTNNB1-mut) and 66 (75%) were wild-type (CTNNB1-WT). Median follow-up was 60 mo. Recurrence occurred in 13/88 (15%) patients. Recurrence rates were not significantly different between patients with CTNNB1-mut and CTNNB1-WT tumors (14% vs. 15%, P=0.86). Recurrence-free survival and overall survival were not significantly different (recurrence-free survival hazard ratio: 0.97, 95% confidence interval: 0.27–3.52, P=0.96; overall survival hazard ratio: 0.23, 95% confidence interval: 0.03–1.71, P=0.15). Mismatch repair deficiency was more prevalent in CTNNB1-WT compared with CTNNB1-mut tumors (46% vs. 14%, P=0.01); prevalence of POLE mutations and aberrant p53 were not significantly different. In contrast to patients with low-risk EEC, no differences in recurrence or survival were found in patients with HIR EEC with CTNNB1-mut compared with CTNNB1-WT tumors.

PAX8 Positivity, Abnormal p53 Expression, and p16 Negativity in a Primary Endometrial Squamous Cell Carcinoma: A Case Report and Review of the Literature

Primary endometrial squamous cell carcinoma (PESCC) is a rare entity. As the clinicopathologic features and the immunophenotype have not been completely defined yet, here we report our experience and review of the literature on this topic. A 73-yr-old nulliparous woman presented with pelvic pain and vaginal bleeding. Endometrial biopsy showed a carcinoma with squamous differentiation infiltrating the myometrium. Total hysterectomy with bilateral salpingo-oophorectomy and selective pelvic lymphadenectomy was performed. Definitive diagnosis was squamous carcinoma of the endometrium, with one lymph node metastasis (stage IIIC1). Immunohistochemistry evidenced immunoreactivity of the tumor cells for cytokeratin 5, p63, cytokeratin 7, PAX8, PTEN, and cyclin D1, aberrant p53 overexpression, and Ki-67 reactivity in ~70% of the tumor cells. Estrogen and progesterone receptor, PAX2, WT1, and p16 were negative. Our case was the first PAX8-positive PESCC in the literature, underlining the Mullerian system origin of this neoplasm. Abnormal p53 expression of this case confirmed its role in the pathogenesis of PESCC. Further studies on a large number of cases are needed to better understand the pathologic features and the immunophenotype of PESCC.

Prevalence and Prognostic Significance of PIK3CA Mutation and CNV Status and Phosphorylated AKT Expression in Patients With Cervical Cancer Treated With Primary Surgery

Currently, there are limited and conflicting reports on the prognostic utility of PIK3CA and associated pathway markers for cervical cancers treated with primary surgical management. Moreover, current studies are lacking complete characterization of adjuvant treatment with RT and/or chemotherapy. We aimed to document the prevalence, clinicopathologic, adjuvant treatment details, and prognostic value of PI3K/AKT pathway mutations and copy number variation and phosphorylated AKT status in patients with cervical cancers treated with primary surgery. A clinicopathologic review was performed on a retrospective cohort of 185 patients with cervical cancer, treated with primary surgery at a single tertiary institution. Next-generation sequencing and digital PCR was used to determine PI3K/AKT pathway mutational status and PIK3CA copy number variation, respectively, and fluorescent immunohistochemistry measured phosphorylated AKT expression. In all, 179 of 185 (96.8%) of tumors were successfully sequenced; 48 (26.8%) were positive for PI3K/AKT pathway mutations—the majority (n=37, 77.1%) PIK3CA mutations. PIK3CA mutation was associated with pathologically positive lymph nodes [12 (32%) vs. 22 (16%); P=0.022] and indication for postoperative chemoradiotherapy [17 (45.9%) vs. 32 (22.5%); P=0.004]. On multivariable analysis, PIK3CA status was not associated with overall survival (P=0.103) or progression-free survival (P=0.240) at 5 yrs, nor was PIK3CA copy number variation status. phosphorylated AKT ≤ median significantly predicted for progression-free survival [multivariable hazard ratio 0.39 (0.17–0.89; P=0.025)] but not overall survival (P=0.087). The correlation of PIK3CA with pathologic positive lymph node status yet lack of association with survival outcomes may be due to the use of adjuvant postoperative therapy. PIK3CA assessment before radical hysterectomy may help identify patients with a higher risk of node-positive disease.

Programmed Death Ligand-1 (PD-L1) Expression in Cervical Squamous Cell Carcinoma: Does it Correlate With Outcomes?

Cervical cancer is one of the most common gynecological malignancies. Upregulation of programmed death ligand-1 (PD-L1), an immunoregulatory protein, is associated with an adverse outcomes in several malignancies. Most studies evaluating PD-L1 expression in cervical squamous cell carcinoma (CSCC) lack data on outcomes. In this study, we correlate PD-L1 expression with clinicopathologic factors and clinical outcomes in invasive CSCC. Seventy-three cases of CSCC from 2010 to 2018 were immunostained for PD-L1. A combined positive score (CPS) of ≥1 and ≥10 was correlated with age, stage, and survival outcomes. Kaplan-Meier curves for progression-free survival and overall survival were plotted and compared using the log-rank test. Cox regression analysis was performed to identify significant prognostic factors (2-tailed P<0.05 was considered statistically significant). With CPS ≥1 or ≥10 as the cut-off, PD-L1 was positive in 52/73 (71.2%) and 23/73 (31.5%) of cases, respectively. PD-L1 positive patients present at a higher stage of disease, especially those with CPS ≥10. With CPS of ≥10 as the cut-off, the 5-yr progression-free survival and 5-yr overall survival were significantly lower (P = 0.034 and 0.012, respectively). Only stage was statistically significant for worse overall survival on multivariate analysis. PD-L1 positive patients present at a higher stage of disease, and stage is an independent prognostic indicator for adverse outcomes in CSCC. This study highlights the potential of PD-L1 targeted therapy in patients with CSCC.

Performance Characteristics of Endometrial Sampling in Diagnosis of Endometrial Carcinoma

Outpatient endometrial biopsy can give false-negative results, with a 0.9% reported posttest probability for endometrial carcinoma (EC) after a negative result. Our objective was to determine if there has been any improvement in the performance characteristics of endometrial biopsy over the last 15 yr. All hysterectomy specimens with a diagnosis of EC or atypical hyperplasia (AH), reported between May 2011 and May 2015, were identified and cross-referenced for any negative endometrial sampling results during the 5 yr before hysterectomy. Negative endometrial samples were defined as either benign findings or insufficient/nondiagnostic, excluding those diagnosed as AH or EC and those for which follow-up sampling was recommended because of atypia. Of 1677 hysterectomy specimens showing AH or EC there were previous negative biopsies in 172: 116 benign and 56 insufficient/nondiagnostic. Over the same period 22,875 negative endometrial biopsy specimens were reported in our region. The posttest probability of having EC or AH in the hysterectomy specimen, given a negative endometrial biopsy result, was 0.74%. In a subset of 90 cases in which a negative biopsy was followed by a diagnosis of AH or EC in a hysterectomy specimen, the slides were independently reviewed. There were no cases where a diagnosis of carcinoma was missed. In 12 samples atypia or possible atypia was identified, and the level of agreement with the original diagnosis was excellent κ=0.83±0.05. In a prospective comparison of examination of 3 levels from each block versus a single slide in 319 cases, the routine preparation of additional slides did not yield clinically significant information. Although there has been evolution in the diagnostic criteria for AH and for recognition of morphologically subtle forms of AH or EC, our results demonstrate a significant lack of sensitivity of outpatient endometrial sampling in the diagnosis of endometrial malignancy/premalignancy. The sensitivity problems are mainly attributable to failure to sample abnormal endometrium. Independent review of slides or examination of additional levels did little to increase the diagnostic yield.

Ovarian Clear Cell Carcinoma and Markers of Epithelial-Mesenchymal Transition (EMT): Immunohistochemical Characterization of Tumor Budding

Tumor budding, largely considered a manifestation of epithelial-mesenchymal transition (EMT) is an established prognostic marker for several cancers. In a recent study, tumor budding was associated with poor clinical outcomes in early-stage ovarian clear cell carcinoma. Here, we evaluated the immune expression of 3 proteins shown to be associated with EMT (E-cadherin, β-catenin, and glypican-3) in 72 primary tumors of ovarian clear cell carcinoma with median follow-up of 39.47 mo. E-cadherin and β-catenin expression was further evaluated in tumor buds in 29 (40%) cases. In the tumor mass, diffuse membranous expression of E-cadherin and β-catenin was seen in 83% (60/72) and 81% (58/72) cases, respectively. Nuclear accumulation of E-cadherin was seen in 7 (10%) cases, while none of the cases showed nuclear β-catenin expression. Glypican-3 expression was diffuse in 33.3% (24/72), patchy in 29.2% (21/72), and absent in 37.5% (27/72) cases. Evaluation of tumor buds showed aberrant patterns of expression (complete loss/cytoplasmic accumulation/diminished, discontinuous incomplete membranous staining) of E-cadherin in 29/29 (100%) and of β-catenin in 26/29 (90%) cases. E-cadherin, β-catenin, and glypican-3 expression in the main tumor mass had no association with stage, lymph node status, recurrent/progressive disease, status at last follow-up, survival and histopathologic features (P>0.05). Our finding of aberrant expression of both E-cadherin and β-catenin in tumor buds indicates involvement of Wnt signaling pathway/EMT in tumor budding and outlines its significance as a prognostic marker especially for early-stage ovarian clear cell carcinoma.

Ovarian RASoma With Mesonephric-like Adenocarcinoma and Mixed Mullerian Components: A Case Report With Molecular Analysis Demonstrating Multidirectional Mullerian Differentiation

Gynecologic carcinomas with RAS mutations may show a wide spectrum of histologic types, including mixed types. We present the case of a 63-yr-old patient diagnosed with an ovarian tumor harboring a mesonephric-like adenocarcinoma in a background of mixed mesonephric-like, mucinous, and endometrioid components. Molecular analysis revealed that all 3 components shared the same clonal KRAS mutation (p.G12A) and chromosome 1q gain. Based on shifts in clonality, copy number gains, and acquisition of an additional mutation, our data suggest that the mucinous component likely constituted the substrate from which the mesonephric-like and endometrioid components arose.

Adult Granulosa Cell Tumour With Heterologous Adipocytic Differentiation: Report of a Unique Case

Adult granulosa cell tumor is the most common malignant ovarian sex cord-stromal tumor and heterologous elements, in the form of hepatocytes or mucinous epithelium, have rarely been described in these neoplasms. Here, we report an adult granulosa cell tumor in a 61-year-old woman with classic and luteinized elements and exhibiting a previously unreported feature in the form of foci of mature adipocytes. In reporting this case, we review heterologous adipocytic elements and other heterologous elements in ovarian sex cord-stromal tumors and speculate on the pathogenesis of the adipocytic differentiation.

Ovarian Malignant Mixed Germ Cell Tumor Composed Mainly of a Polyembryoma Pattern With Vasculogenic Mesenchymal Tumor Components

Ovarian germ cell tumors composed of numerous well-formed embryonal bodies have been described as exhibiting a “polyembryoma pattern.” In addition, some germ cell tumors are occasionally concomitant with neoplastic vascular proliferation. These include angiosarcomas and the recently reported mediastinal vasculogenic mesenchymal tumors. A 9-yr-old Japanese girl underwent surgery for a right ovarian tumor. Histologically, the polyembryoma pattern, nongestational choriocarcinoma, and vasculogenic lesions characterized by a neoplastic repetition of embryonic vasculogenesis have been intermingled. The polyembryoma pattern consisted of numerous complete and incomplete embryonal bodies and glandular structures resembling adult-type and fetal-type intestines. Vasculogenic lesions were composed of variously developed neoplastic vessels within the myxomatous stroma, which extended well beyond one low-power (40×) microscopic field. We concluded that the vasculogenic lesion in our case was the ovarian counterpart of the mediastinal vasculogenic mesenchymal tumor. After the surgery, the patient was administered adjuvant chemotherapy and was alive with no evidence of recurrence or other malignancy at 28 mo postsurgery.

HPV42-associated Seborrhoeic Keratosis-like Lesion of the Cervix: First Reported Case With High-grade Morphology

Seborrheic keratosis-like lesion (SKLL) is an extremely rare, morphologically distinct lesion occurring in the cervix and vagina that differs histologically from usual squamous intraepithelial lesions in these sites, by bearing close resemblance to cutaneous seborrheic keratosis and lacking koilocytosis. Like many vulvar seborrheic keratoses, which are associated with low-risk human papillomavirus (HPV), an association between SKLL and low-risk HPV is suggested based on the identification of HPV42, regarded as a low-risk genotype, in 4 of 8 reported cases. We report a further HPV42-associated SKLL of the cervix which differs from the previously reported cases by the presence of high-grade morphology and block-type p16 immunoreactivity. This novel finding challenges the classification of HPV42 as a low-risk genotype and expands the reported morphologic spectrum of SKLL, suggesting that they may not always be clinically indolent.

Tumor to Tumor Metastasis: A Case Report of Metastatic Angiosarcoma to an Ovarian Brenner Tumor and Review of the Literature

While angiosarcoma metastatic to the ovary is rare, metastatic angiosarcoma to an ovarian tumor has never been reported in the literature, so far. We report a case of a 61-yr-old postmenopausal woman with history of breast cancer, presenting with metastatic angiosarcoma to an ovarian Brenner tumor. Initially at the frozen section examination, on limited sampling, and without knowledge of the patient’s history, a diagnosis of at least proliferating Brenner tumor was rendered. Upon review of permanent sections, an intermixed angiosarcoma component was identified within Brenner tumor. Tumor to ovarian tumor metastasis is a rare phenomenon, with only 18 cases reported in the last 50 yr. It poses diagnostic challenges during sampling and histopathologic interpretation. Detailed clinical history, careful gross examination and sampling are important to recognize the separate tumor components.

Malignant Lymphoma of the Ovary: A Diagnostic Pitfall of Intraoperative Consultation

Primary ovarian lymphomas are rare, but can potentially evoke diagnostic problems. We present a case of ovarian lymphoma, in which an ambiguous intraoperative pathologic report led to overtreatment (unnecessary surgery). A 73-yr-old woman with fatigue and low-grade fever was diagnosed as having a left ovarian tumor by imaging modalities. Exploratory laparotomy was carried out to confirm the diagnosis. The frozen tissue sections of the ovarian tumor showed condensed proliferation of atypical round cells accompanied with a few small lymphocytes. The pathologists could not determine whether this tumor was a lymphoma or another malignancy (eg, dysgerminoma). Hence, they reported it to gynecologists who operated as simply a malignant tumor in order to evade misdiagnosis. On the basis of the inconclusive pathologic report, the gynecologists decided to change the planned laparotomy to total hysterectomy with bilateral salpingo-oophorectomy and pelvic lymph node dissection. A postoperative paraffin section–based pathologic diagnosis was diffuse large B-cell lymphoma of the ovary, which basically does not require surgical treatments. Subsequently, chemotherapy for B-cell lymphoma was initiated, and no lymphoma recurrence has been reported to date. A more robust preoperative discussion between the gynecologists and the pathologists might have avoided the overtreatment.

Ovarian Low-grade Basaloid Carcinoma Arising in Brenner Tumor: A New Variant of Malignant Brenner Tumor

Brenner tumors are uncommon ovarian neoplasms, most of which are benign, although borderline and malignant variants occur. We report 2 unusual ovarian neoplasms composed of an admixture of typical benign Brenner tumor and a low-grade epithelial neoplasm which we designate as low-grade basaloid carcinoma. The latter component morphologically and immunohistochemically resembled “salivary gland-type/myoepithelial” neoplasms with variable positive staining with cytokeratins, p63, S100, and CD117. One tumor exhibited aggressive behavior with local recurrence and distant metastasis. This neoplasm exhibited focal “high-grade” transformation with diffuse mutation-type p53 staining, in contrast to the wild-type immunoreactivity in the low-grade component. As far as we are aware, such neoplasms have not previously been reported in the literature and this represents a newly described morphologic variant of malignant Brenner tumor.

Immunohistochemical Loss of DPC4 in Tumors With Mucinous Differentiation Arising in or Involving the Gynecologic Tract

DPC4 immunohistochemistry (IHC) is usually part of the work-up of mucinous neoplasms in the ovary where the distinction between an ovarian primary and metastatic pancreaticobiliary adenocarcinoma (PanACa) must be made. Although DPC4 IHC is lost in about 55% (46%–61%) of PanACas and typically retained in most primary ovarian mucinous neoplasms, no study has evaluated the expression of this marker in a large cohort of neoplasms arising in or involving gynecologic (GYN) organs. In this study, we retrospectively analyzed the expression of DPC4 IHC in a total of 251 tumors and lesions related to the GYN tract in which DPC4 IHC stain was performed during the initial pathology evaluation. Of these, 138 were primary GYN tumors and lesions, 31 were metastatic GYN tumors involving non-GYN sites, and 83 were metastatic non-GYN tumors involving the GYN tract. We identified 27 cases with loss of DPC4 IHC expression of which 20 cases met the inclusion criteria (i.e. clinical information was available to determine the site of tumor origin). We observed that loss of DPC4 nuclear expression was most commonly seen in tumors of endocervical origin (n=7), of which 5 were gastric-type cervical adenocarcinomas (GCxACa) and 2 were usual-type cervical adenocarcinomas, either primary or metastatic. This was followed by tumors of the pancreaticobiliary tract (n=5), ovary (n=2), and appendix (n=1). In addition, 1 gastric-type vaginal adenocarcinoma (GVaACa) also showed loss of DPC4. Our findings indicate that in female patients with mucinous neoplasms involving the ovary or other sites, with loss of DPC4 by IHC, and negative pancreaticobiliary imaging, the possibility of an occult GCx/GVaACa, and rarely an ovarian primary must be considered.

CDX2, SATB2, GATA3, TTF1, and PAX8 Immunohistochemistry in Krukenberg Tumors

Twenty-six Krukenberg tumors (16 lower gastrointestinal, 4 upper gastrointestinal, and 6 of unknown origin) and their primaries when known were stained with CDX2, SATB2, GATA3, TTF1, and PAX8 using a tissue microarray containing predominantly or exclusively signet ring cells. The most common primary was appendiceal mixed adenoneuroendocrine carcinoma. CDX2 and SATB2 were positive in all known lower gastrointestinal primary tumors and negative in nearly all known upper gastrointestinal primary tumors. Primaries showed identical immunophenotypes to their metastases. Among cases of unknown primary origin, 3 were positive and 3 were negative for CDX2 and SATB2. Chest images, upper endoscopies, colonoscopies, appendectomies, and mammogram were performed with negative results in all, 4, 2, 2, and 1 cases, respectively. No cystoscopies were attempted. PAX8, GATA3, and TTF1 were negative in all cases. The literature was reviewed with emphasis on immunohistochemistry of signet ring cell–containing carcinomas from the appendix, colon, stomach, breast, lung, and bladder. Three quarters of gastric primaries stain for CDX2 and only rare examples stain for SATB2. Colorectal primaries (most of them) and appendiceal primaries (all of them) are positive for CDX2 and SATB2. GATA3 stains almost all breast primaries and approximately half of bladder primaries. All pulmonary primaries are positive for TTF1. PAX8 is negative in the gastric, colorectal, and appendiceal primaries reported. This study shows that the panel of immunostains is useful in confirming the site of origin of a metastatic Krukenberg tumor when one is known and has limited diagnostic value for diagnosing metastases of unknown origin.

Expression of the Immune Checkpoints LAG-3 and PD-L1 in High-grade Serous Ovarian Carcinoma: Relationship to Tumor-associated Lymphocytes and Germline BRCA Status

Ovarian high-grade serous carcinomas (HGSC) have shown lackluster responses to immunotherapies targeting the PD-1/PD-L1 axis, perhaps due to the coexistence of other mechanisms of immune evasion in this tumor type. Lymphocyte activation gene-3 (LAG-3) is another inhibitory immune checkpoint often expressed on tumor-associated lymphocytes which is targeted by drugs currently in clinical trials. Forty-eight HGSC with known germline BRCA mutation status were immunohistochemically stained for LAG-3, CD8, and FOXP3. Positive tumor-associated lymphocytes were enumerated and averaged over 10 high-power fields (HPF). PD-L1 immunostaining was also preformed and expression was evaluated on tumor cells and using the combined positive score (CPS). The average number of LAG-3-positve tumor-associated lymphocytes was 6/HPF (range: 0–25.6). Cytotoxic (CD8+) T cells averaged 30/HPF (range: 0–168.9), and regulatory (FOXP3) cells averaged 6.6/HPF (range: 0–76.3). Tumoral PD-L1 expression of ≥1% was observed in 27% (13/48) of cases, with only 8% (4/48) showing >5% staining; 81% (39/48) cases had a CPS ≥1. LAG-3-positive lymphocytes and PD-L1 expression were positively correlated, even after controlling for the overall level of CD8 and FOX3P+ lymphocyte infiltration. Germline BRCA status was not significantly associated with LAG-3, CD8, FOXP3, or PD-L1 expression. These findings indicate that immunotherapies targeting LAG-3 may benefit some ovarian HGSC patients, particularly when used in conjunction with anti-PD-1/PD-L1 approaches. The typically limited expression of LAG-3 and PD-L1 suggests that immunotherapeutic response may be muted in most HGSC even with a combination approach.

Malignant Sex Cord-Stromal Tumor, Not Otherwise Specified, Harboring FOXL2, p53, and TERT Promoter Mutations: Report of a Case

Rare sex cord-stromal tumors of the ovary cannot be further subclassified and are therefore designated “sex cord-stromal tumor-not otherwise specified.” These tumors have highly varied morphology, and the literature describing them is limited. Herein, we report the pathology and clinical course of a 46-yr-old woman diagnosed with sex cord-stromal tumor-not otherwise specified. The tumor was composed predominantly of juvenile granulosa cell tumor histology, with elements of thecoma, adult granulosa, Sertoli, as well as poorly differentiated epithelioid and sarcomatoid components. Next-generation sequencing revealed a FOXL2 C134W mutation, seen most commonly in adult granulosa cell tumors, as well as mutations in TP53 (V172F) and TERT promoter (-124C>T). The patient exhibited an aggressive clinical course involving rapid recurrence with distant metastases that responded to 4 cycles of cisplatin, bleomycin, and etoposide.

A Case of Recurrent Vulvar Carcinoma With Cardiac Metastasis: Case Report and Review of the Literature

A 67-yr-old female patient was diagnosed with squamous cell vulvar carcinoma and treated with a radical vulvectomy and bilateral sentinel lymphadenectomy. Three months after the surgery, the patient presented with local recurrence and underwent surgical excision of the mass, followed by chemotherapy. Eight months later, the patient was admitted due to weakness and pleural effusion. The patient underwent a chest computed tomography and echocardiogram, which revealed a large mass in the right ventricle penetrating into the pericardium and an additional mass residing on the tricuspid valve. She underwent a pericardial biopsy, and the pathology revealed a moderately differentiated squamous cell carcinoma metastasis. The patient was admitted thereafter in the oncological department for additional chemotherapy treatment. Because of a rapid deterioration in the patient’s condition, only palliative treatment was given, and the patient died shortly after. Secondary cardiac tumors are very rare and have not been extensively studied in oncology. Therefore, optimal management is not entirely clear. It is extremely rare for vulvar cancer to metastasize to the heart, and only a handful of cases have been reported in the literature.

Intralymphatic Rosai-Dorfman Disease Associated With Vulvar Lymphedema: A Case Report of an Extremely Rare Phenomenon

Sinus histiocytosis with massive lymphadenopathy, also known as Rosai-Dorfman disease (RDD), is a self-limited histiocytic disorder of unclear etiology which most commonly presents with cervical lymphadenopathy. Purely extranodal presentation of RDD is uncommon, and isolated intralymphatic/intravascular confinement of this entity has not previously been described. We report a 16-yr-old female who presented with vaginal swelling and mass-like enlargement of the right labia. The mass had been present for nearly a year without pain or tenderness. Clinically, the lesion was thought to be a Bartholin gland cyst. Following surgical resection, histologic examination demonstrated a hypocellular myxedematous stroma with a mixture of ectatic thin and thick-walled vessels within which there were numerous collections of histiocytes, lymphocytes, and plasma cells. The histopathologic differential diagnosis included localized vulvar lymphedema, a specialized genital tract neoplasm, and childhood asymmetric labium majus enlargement. The histiocytes showed occasional plasma cells and lymphocytes within their cytoplasm, consistent with emperipolesis. Immunohistochemical studies showed that the histiocytes expressed CD163 and S100, while ERG and D2-40 highlighted their intralymphatic confinement, ultimately leading to the diagnosis of intralymphatic RDD. Intralymphatic RDD may present as vulvar lymphedema and can potentially mimic other myxedematous neoplasms of the vulvovaginal region.

Multiple Epidermolytic Acanthomas: Rare Vulval Lesions Which May be Mistaken for Viral Warts

Epidermolytic acanthoma is a rare benign lesion that most often presents as a solitary or multiple small papular lesions on the trunk, face, limbs or external male genitalia. Only a small number of cases have been reported occurring on the vulva and clinically and histologically they may mimic and be misdiagnosed as viral warts. We report 2 cases of multiple epidermolytic acanthomas localized to the vulva. Molecular tests (in situ hybridization and polymerase chain reaction) showed no evidence of human papillomavirus infection and p16 staining was negative. We stress the need for pathologists to consider epidermolytic acanthoma in the differential diagnosis of multiple vulval lesions resembling viral warts.

HPV-independent Vulvar Squamous Cell Carcinoma is Associated With Significantly Worse Prognosis Compared With HPV-associated Tumors

Vulvar squamous cell carcinomas (VSCC) represent the most common carcinoma of the female external genitalia, with increasing incidence. Although high-risk human papillomavirus (HPV) infection has long been implicated in the majority of cervical and anal squamous cell carcinomas, there is uncertainty about its prevalence and prognostic impact in VSCC. In this study, we conducted a retrospective integrated morphologic and multimodal HPV analysis of a cohort of 114 VSCC cases treated at the Princess Margaret Cancer Centre/University Health Network, Toronto, Canada between 2000 and 2010. VSCC histology was reviewed. We analyzed the cohort for HPV using polymerase chain reaction based method, and tissue microarray DNA and RNA in situ hybridization (ISH), and p16 immunohistochemistry. Among the 114 cases (age 70±16 yr), 36.7% of cases were classified as having histomorphology of HPV infection. HPV was detected in 31.9% (polymerase chain reaction), 14.0% (DNA ISH), and 27.3% (RNA ISH) of cases. p16 immunohistochemistry was positive in 37.8% of cases. On univariate analysis, HPV morphology (P=0.009), p16+ (P=0.00013), DNA ISH+ (P=0.021), and RNA ISH+ (P=0.00061) were associated with better 5-yr progression-free survival. DNA ISH+ (P=0.049) was associated with better 5-yr overall survival. On multivariate analysis, HPV morphology (P=0.033), p16+ (P=0.01), and RNA ISH+ (P=0.035) were associated with better 5-yr progression-free survival. In conclusion, a subset of VSCC is associated with HPV, which correlates with better outcome. Relatively inexpensive tests such as histomorphologic evaluation, p16 immunohistochemistry, and HPV RNA ISH can be used to predict outcome in VSCC. Therefore, routine reporting of HPV status in VSCC is recommended.

P16 Expression in Primary Vulvar Extramammary Paget Disease

P16 immunohistochemistry has been widely used in facilitating the diagnosis of human papillomavirus (HPV)-related usual type vulvar intraepithelial neoplasm. However, studies of p16 expression in primary vulvar extramammary Paget disease (EMPD) are limited. We assessed the p16 expression by immunohistochemistry in 40 cases of primary vulvar EMPD, including 34 cases of intraepithelial vulvar EMPD and 6 cases of invasive vulvar EMPD and correlated p16 expression patterns with disease progression. Overall, p16 expression was present in 36 cases (90%), including 20 cases (50%) with focal staining pattern and 16 cases (40%) with diffuse staining pattern. All 20 cases with focal p16 staining pattern were intraepithelial vulvar EMPD. Diffuse p16 staining pattern was present in 10/30 cases (33.3%) of intraepithelial EMPD and in 6/6 cases (100%) with invasive vulvar EMPD. Negative p16 staining was present in four intraepithelial EMPD cases. Using a highly sensitive RNA in situ hybridization method, we did not detect high-risk HPV in the selected 10 cases with diffuse p16 staining pattern, including 6 cases of intraepithelial EMPD and 4 cases of invasive EMPD. We also observed that intraepithelial EMPD had predominantly cytoplasmic p16 immunoreactivity, whereas nuclear p16 immunoreactivity was mainly seen in invasive EMPD components. Our study demonstrated that the p16 positive immunostaining was seen in the majority of primary vulvar EMPD which is not related to HPV infection. Therefore, knowing the overlapping p16 immunostaining patterns in vulvar EMPD and usual type vulvar intraepithelial neoplasm is important to render the correct diagnosis.

An Exceptional Vulvar Tumor: Myeloid Sarcoma of the Labia Majora

Vulvar malignancies are rare and have diverse origins and presentations. The majority of these tumors are squamous cell carcinoma. An ulcerating vulvar tumor was found in a 74-yr-old woman presenting with fatigue and leukocytosis. Tumor biopsy revealed infiltration of blastoid cells from myeloid origin. Through bone marrow aspiration chronic myelomonocytic leukemia was diagnosed, of which the vulvar tumor was a rare extramedullary disease manifestation termed myeloid sarcoma. Limited palliative treatment was instated with a focus on the patient’s quality of life. Myeloid sarcoma (chloroma; granulocytic sarcoma) is a mass of myeloblasts occurring in cases of myeloid disease. Manifestations in most organ systems have been described. Presentation in gynecologic areas is reported in a few case reports, to which we now add our experience.

Misdiagnosis of High-grade Serous Ovarian Cancer With BRCA Mutation as Endometriotic Cyst Due to Its Unique Gross Morphology: A Case Report and Literature Review

It is believed that high-grade serous ovarian cancer (HGSOC) is a solid or multilocular-solid cancer. Here, we report the case of a 40-yr-old woman with a left ovarian unilocular cyst. Ultrasonography and computed tomographic examination confirmed that the cyst was thin-walled and homogenous in thickness without mural nodules. It was considered to be an endometriotic cyst. Left ovarian cyst excision specimens proved it to be HGSOC after pathologic examination. Therefore, the patient underwent radical surgery for HGSOC. Pathologic examination of radical resection specimens confirmed that the HGSOC was still in FIGO stage IA and no fallopian tube lesion was found. Considering that the patient had a history of breast cancer in both the breasts at a young age, it was hypothesized that the breast cancer susceptibility gene (BRCA) gene may have a germline mutation. Next-generation sequencing confirmed the BRCA1 (c.3770_3771delAG) germline mutation in this patient. Previous studies have reported the special morphological characteristics and growth pattern of HGSOC with BRCA mutation in the advanced stage. Our case demonstrates that HGSOC with the BRCA mutation can also be a unilocular cyst with a thin wall and uniform thickness without a mural nodule, and in the early stage, may have unique gross morphology.

Expression of Potential Biomarker Targets by Immunohistochemistry in Cervical Carcinomas

There have been few clinically useful targetable biomarkers in uterine cervical carcinomas. Estrogen receptor (ER), HER2, and fibroblast activation protein (FAP) are potential therapeutic or theranostic targets in other gynecologic and genitourinary carcinoma types. We determined the immunohistochemical expression patterns of these markers in treatment-naive cervical carcinoma, and whether expression correlated with clinical outcomes after definitive chemoradiation therapy. Tissue microarrays were created from 71 patient samples taken before therapy (57 squamous cell carcinomas and 14 nonsquamous cell carcinomas) and stained for ER, HER2, and FAP. ER was positive in 25/70 cases (36%). Of 66 tumors with evaluable HER2 staining, only 1 had positive (3+) staining (3%, positive for HER2 amplification by fluorescence in situ hybridization), and 1 had equivocal (2+) staining (negative for amplification by fluorescence in situ hybridization). The remainder were negative for HER2 overexpression. FAP expression was widely variably in the tumor stroma. ER positivity and FAP expression did not correlate with cervical recurrence, pelvic recurrence, distant recurrence, or cancer death. In conclusion, HER2 amplification is very rare in nonmetastatic treatment-naive cervical carcinomas, but if present, could represent a target for antibody therapy. ER and FAP were expressed in a subset of tumors, but expression did not correlate with clinical outcomes. These immunohistochemical markers do not demonstrate prognostic significance in treatment-naive cervical cancer, but they may have utility in targeted therapy or imaging.

International Endocervical Adenocarcinoma Criteria and Classification (IECC): An Independent Cohort With Clinical and Molecular Findings

Recently, the International Endocervical Adenocarcinoma Criteria and Classification (IECC) has reorganized the classification of endocervical adenocarcinomas (ECAs), separating them into human papilloma virus (HPV)-associated (HPVA) and HPVA independent (HPVI) categories. In this study, we sought to revalidate the IECC clinical findings in an independent cohort and assess the mutational differences between HPVA and HPVI ECAs using next generation sequencing. Consecutive cases of ECAs were reclassified under the IECC. Clinicopathologic information was collected and tissue was sent for targeted next-generation sequencing in 33 genes. Associations between HPV status, clinicopathologic parameters and mutation status, with survival were evaluated. The series comprised of 85/100 HPVA (63 HPVA-usual type, 4 villoglandular, 3 mucinous intestinal, 15 mucinous not otherwise specified) and 15/100 HPVI (9 gastric, 4 mesonephric, 1 clear cell, 1 not otherwise specified). HPVA ECAs presented at a lower age (P=0.001), smaller tumor sizes (P=0.011), less margin positivity (P=0.027), less Silva pattern C (P=0.002), and lower FIGO stages (P=0.020). HPVA had superior survival compared with HPVI ECA [overall survival (P=0.0026), disease-specific survival (P=0.0092), and progression-free survival (P=0.0041)]. Factors that correlated with worse prognosis irrespective of HPV status were FIGO stage, positive margins and lymphovascular invasion (P<0.05). TP53 mutations were detected in a significantly higher proportion of HPVIs than HPVAs (P<<0.001). The study revalidates the IECC system by reaffirming the clinical and prognostic differences between HPVA and HPVI ECAs in an independent dataset.

Primary Ovarian High-grade Neuroendocrine Carcinoma With Merkel Cell–like Immunophenotype Arising in a Teratoma

Ovarian high-grade neuroendocrine carcinomas (NECs) (small cell and large cell NEC) are rare neoplasms. They may arise in association with other ovarian tumors, most commonly epithelial neoplasms and rarely teratomas. We report a case of an 19-yr-old female with bilateral ovarian teratomas with a high-grade NEC (immunohistochemically positive with chromogranin, synaptophysin, and CD56 and MIB1 proliferation index in excess of 90%) arising within one of these. Although CK20 was negative, the NEC exhibited an immunophenotype suggestive of a Merkel cell carcinoma with diffuse positive staining with FLI-1, SATB2 and neurofilament, markers which are preferentially expressed in Merkel cell carcinoma compared with other NECs. There was also diffuse staining for SALL4. Immunohistochemistry and molecular studies for Merkel cell polyomavirus were negative. Immunohistochemical staining for CK20, FLI-1, SATB2, neurofilament, and SALL4 was performed in 6 additional primary ovarian high-grade NECs; One, 5, 5, 1, and 0 cases were positive for CK20, FLI-1, SATB2, neurofilament, and SALL4, respectively, usually with very focal immunoreactivity. Pathologists should be aware of these potential unexpected staining patterns in ovarian NECs as positivity may result in consideration of other neoplasms.

Ovarian Steroid Cell Tumor in an Adolescent With Von Hippel-Lindau Syndrome: A Case Report and Review of the Literature

Von Hippel-Lindau (VHL) syndrome is an autosomal dominant genetic disorder caused by germline mutation of the VHL gene. It is associated with multiple neoplasias including hemangioblastoma, clear cell renal cell carcinoma, pheochromocytoma, and neuroendocrine tumors. Ovarian tumors are extremely rare in this syndrome. We describe the case of a 16-yr-old girl with a previous diagnosis of bilateral pheochromocytoma and several pancreatic neuroendocrine tumors in VHL syndrome context. Follow-up abdominal-pelvic magnetic resonance imaging revealed a 33 mm, well-circumscribed nodule in the right ovary. The patient was submitted to laparoscopic right salpingo-oophorectomy. Microscopically, the tumor consisted of polygonal cells with abundant microvacuolized clear cytoplasm arranged in a solid pattern. The neoplastic cells were immunohistochemically positive for inhibin and calretinin. A diagnosis of ovarian steroid cell tumor was made. Only 4 cases with this association have been reported to date. Of the previously described cases, only one concerns a child; the others were all adult women. All of them had a previous diagnosis of VHL syndrome and presented with secondary amenorrhea and/or hirsutism due to testosterone-secreting ovarian steroid cell tumors. Although extremely rare, the association between VHL syndrome and ovarian steroid cell tumor has been reported, and our case suggests there is a link between the 2 entities.

Folate Receptor Alpha Expression and the Tumor Immune Microenvironment in Patients with Cervical Cancer

Folate receptor α (FRα) is a cell-surface protein and an attractive target for cancer treatment. We investigated the association between FRα expression and the tumor immune microenvironment in patients with cervical cancer. We examined whole tumor sections of 123 patients with cervical cancer: 67 and 56 sections of squamous cell carcinoma (SCC) and non-SCC, respectively. FRα expression was assessed using immunohistochemical staining with the anti-FRα monoclonal antibody clone 26B3. Programmed death-ligand 1 (PD-L1) expression was assessed using a combined positive score (CPS). The intratumoral CD3 and CD8 cell densities were calculated as the average number of positive cells in five independent areas. FRα-positivity was identified in 72.4% of the patients, and it differed by histology (SCC vs. non-SCC; 55.2% vs. 92.9%, P<0.001). PD-L1 status was positive (CPS ≥1) in 75.6% and was more commonly expressed in patients with SCC (SCC vs. non-SCC; 83.5% vs. 66.1%, P=0.02). FRα expression had a weak correlation with PD-L1 expression (r=−0.22, P<0.001) and CD8-positive cells (r=−0.19, P=0.03). FRα-positivity was more frequently observed in the PD-L1 CPS <10 group than in the PD-L1 CPS ≥10 group (81% vs. 64%, P=0.03). FRα-high was significantly associated with poor prognosis, especially in the PD-L1 CPS ≥10 groups (hazard ratio: 4.10, 95% confidence interval: 1.39–12.06, P=0.01). In conclusion, FRα expression was higher in patients with cervical cancer and PD-L1 CPS <10 than in those with CPS ≥10. Targeting FRα expression may be a potential therapeutic strategy for cervical cancer patients with low or negative PD-L1 expression.

BRAF Wild-type, PTEN Mutant Malignant Uveal Melanoma Arising Within a Mature Ovarian Teratoma: A Case Report and Review of the Literature

Mature cystic teratomas are common in women of all ages; however, malignant transformation within them is rare and difficult to diagnosis preoperatively. Primary melanoma of the ovary is exceptionally rare and only occurs in relation to a teratoma where it can originate from sporadic somatic mutagenesis within epidermal junctional melanocytes, through malignant transformation of a benign nevus formed within the mature cystic teratoma or from other well differentiated pigment-containing structures such as the uvea. We present a case of primary malignant melanoma arising within a mature cystic teratoma in a young patient, who ultimately developed widespread metastasis necessitating systemic therapy. Our case highlights the role of molecular medicine not only in forming an understanding the origin of the melanoma, but also guiding targeted systemic therapies. Alongside the case we present a review of the literature describing the incidence of molecular aberrations within melanoma as well as the established and emerging techniques and cytotoxic agents for malignant melanoma.

Tumor-to-Tumor Metastasis of Colorectal Adenocarcinoma to Ovarian Cystadenofibroma: A Case Report and Review of the Literature

Tumor-to-tumor metastasis is being described in different types of tumors and in increasing amount of cases. Being aware of this phenomenon is important, as it affects disease stage and treatment approach. In this report, we descried an incidental histopathologic finding of metastatic adenocarcinoma to an ovarian cystadenofibroma and review cases published previously in the literature.

Primary Ovarian Tumors With Lymphogenic and Hematogenic Metastasis Express High MMP-14, Which Colocalizes With Highly Sulfated Chondroitin Sulfate in the Stroma

Lymphogenic and hematogenic metastases are uncommon in ovarian cancer, especially at presentation. We hypothesized that MMP-14 and MMP-2, CD44, and highly sulfated chondroitin sulfate (CS-E) may be overexpressed in tumors with these metastatic patterns. These molecules are all present in the ovarian tumor microenvironment, wherein they may interact. In an ovarian cancer cohort of 44 patients with metastases in lymph nodes, spleen, and/or liver, the presence of MMP-14, MMP-2, CD44, and CS-E in both the primary tumor and the metastases was determined with immunohistochemistry and related to clinical characteristics. Immunohistochemical expression was found for MMP-14 in all primary tumors as well as in all metastases and for MMP-2 expression in most of the samples. Most primary tumors with synchronous metastases were positive for CS-E, as well as most primary tumors with metachronous lymphogenic metastases. The expression of the MMPs and CS-E in the stroma seemed to colocalize. For CD44 immunohistochemical expression, this relationship was not found. Epithelial MMP-14 on the one hand and stromal CS-E on the other hand seem to be essential players in ovarian cancer with lymphogenic and hematogenic metastases. CD44 expression is not correlated with the other markers. More research on the interaction of these molecules and their role in the process of dissimination of disease is warranted.

Ovarian Combined Low-grade Serous and Mesonephric-like Adenocarcinoma: Further Evidence for A Mullerian Origin of Mesonephric-like Adenocarcinoma

Mesonephric-like adenocarcinomas are rare neoplasms occurring in the uterine corpus and ovary which bear a close morphologic resemblance to cervical mesonephric adenocarcinomas. They also have a similar immunophenotype and harbor similar molecular abnormalities to mesonephric adenocarcinomas and it is debated whether they are truly of mesonephric origin or represent Mullerian neoplasms closely mimicking mesonephric adenocarcinomas. We report an unusual case with bilateral ovarian serous borderline tumors and extraovarian low-grade serous carcinoma (invasive implants). In one ovary, there was a component of mesonephric-like adenocarcinoma. The immunophenotypes of the serous and the mesonephric-like components were distinct and as expected for the individual tumor types (serous component diffusely positive with WT1 and estrogen receptor and negative with GATA3, TTF1 and CD10; mesonephric-like component WT1 and estrogen receptor negative and GATA3, TTF1, and CD10 positive; both components diffusely positive with PAX8 and exhibiting “wild-type” p53 immunoreactivity). In all components (bilateral serous borderline tumors, low-grade serous carcinoma and mesonephric-like adenocarcinoma), an identical KRAS mutation was detected (NM_004985.4): c.35G>A, p.(G12D) proving a clonal association between the serous and mesonephric-like components and excluding a collision neoplasm. This represents the second reported case of a combined ovarian low-grade serous tumor and mesonephric-like adenocarcinoma; in the previously reported case, an identical NRAS mutation was present in both components. These 2 cases provide evidence that ovarian mesonephric-like adenocarcinomas have, at least in some cases, a Mullerian origin and differentiate along mesonephric lines. We present additional evidence for this by reviewing associated findings in published and unpublished ovarian mesonephric-like adenocarcinomas; 8 of 11 of these neoplasms contained other Mullerian lesions in the same ovary, mainly endometriosis and adenomas/adenofibromas.

Risk of Malignancy in Postmenopausal Patients With Ovarian Torsion

Bilateral Signet-ring Stromal Tumor of the Ovary: A Case Report With Next-generation Sequencing Analysis and FOXL2 Mutation Testing

Signet-ring stromal tumor (SRST) is a rare benign stromal neoplasm of the ovary with only a handful of cases reported in the literature. To date, all but one reported cases have been unilateral, and the pathogenesis and underlying genetic abnormalities of this entity are not well characterized. Here we report a case of a 70-yr-old woman with bilateral ovarian SRST, clinically presenting with abdominal distention and rectal bleeding, and bilateral ovarian masses on imaging studies. Total hysterectomy and bilateral salpingo-oophorectomy were performed, revealing bilateral solid ovarian tumors with characteristic signet-ring cell morphology. The immunohistochemical profile—positive steroidogenic factor 1, calretinin, and smooth muscle actin, and negative epithelial membrane antigen—supported the diagnosis of SRST. CTNNB1 mutation and abnormal nuclear beta-catenin expression have recently been reported in 2 SRSTs. However, we did not identify any mutations in 54 oncogenes and tumor suppressor genes (including CTNNB1) by next-generation sequencing analysis, and PCR Sanger sequencing did not reveal FOXL2 C134W mutation, suggesting the possibility of heterogenous pathogenesis of these tumors.

Peritoneal Carcinomatosis From Yolk Sac Tumor in a Postmenopausal Woman Following Chemotherapy for High-grade Ovarian Serous Carcinoma

Cerebellar Metastasis From Ovarian Carcinoma Harboring PIK3CA-Activating Mutation: A “Clear” Explanation for Unexpected “Vertigo”

Brain metastasis is a rare and generally late manifestation of an advanced-stage, high-grade serous ovarian carcinoma. Nowadays, the improved control of intra-abdominal disease by surgery and platinum-based chemotherapy results in a longer survival, allowing distant metastasis to implant and grow in the brain parenchyma. Herein, we describe a unique case of a cerebellar metastasis from clear cell ovarian carcinoma that initially presented as a FIGO Stage IC cancer. Surprisingly, 6 mo after surgery, the patient was in good condition with complete disappearance of symptoms and no evidence of recurrence. This relatively good biologic behavior may be explained by the presence of a PIK3CA-activating mutation in exon 9 which as previously reported in the literature, may be associated with better prognosis. To the best of our knowledge, this is the first reported case of cerebellar metastasis from ovarian clear cell carcinoma. In the presence of neurological symptoms, both clinicians and pathologists must be aware of this rare possibility, to assure correct patient management and effective therapeutic options. Generally, the prognosis of epithelial ovarian cancer patients with brain metastases is poor. PIK3CA mutations could be a good prognostic indicator in clear cell carcinomas.

Claudin-4 Expression is Associated With Survival in Ovarian Cancer But Not With Chemotherapy Response

A Constellation of Rare Gynecological Malignancies and Familial Adenomatous Polyposis Gastrointestinal Adenocarcinoma: A Case Report

Ovarian microcystic stromal tumors (MST) are a rare subtype of sex-cord stromal tumors. We are presenting a case of a MST arising in a patient with familial adenomatous polyposis (FAP) and concurrent colonic adenocarcinoma. During the patient’s workup of an ampullary adenoma associated with her FAP, she was found to have an enlarged uterus with a thickened endometrium and an incidental pelvic mass on the fundus of the uterus. Subsequent imaging identified heterogenous bulky ovaries. This patient underwent surgical resection including a total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, bilateral pelvic sentinel lymph node biopsy during her planned total proctocolectomy and transduodenal ampullectomy. Extensive histologic and immunohistochemical investigations were completed and the final pathology report revealed a unique compilation of International Federation of Gynecology and Obstetrics Stage II, grade 1 endometrioid endometrial adenocarcinoma, bilateral ovarian MST, a sperate pedunculated mass favoring a diagnosis of uterine tumor resembling ovarian sex cord tumor (UTROSCT), 2 distinct adenocarcinomas of the colon (T2N0 and T1N0) and a tubular adenoma of the ampulla. The pathology showed the endometroid adenocarcinoma was β-catenin negative while the MST and UTROSCT both showed nuclear positivity with β-catenin. To our knowledge this is the first reported case of a UTROSCT with concurrent endometrial adenocarcinoma presenting with bilateral ovarian MST’s and adenomatous polyposis coli gene positive FAP colon adenocarcinoma.

Ovarian Metastasis by Gastric-type Endocervical Adenocarcinoma: A Clinicopathologic Description of 12 Cases

Cervical gastric-type adenocarcinoma has a propensity for ovarian metastasis, but the clinicopathologic findings and possible routes of tumor spread have not been well characterized to date. To address these points, we reported 12 cervical gastric-type adenocarcinomas with ovarian metastases from a single institution. Seven patients with gastric-type adenocarcinoma had concurrent endometrial fallopian tube involvement, 5 of which showed tumors confined to the fallopian tube mucosa. Two of these 5 patients died of disease at 2 and 16 mo, and 1 recurred at 18 mo. In the remaining 5 patients, 3 had wide pelvic/peritoneal spread while the other 2 showed no evidence of uterine or tubal involvement. Among them, 1 died of disease at 94 mo, and another relapsed at 20 mo. Morphologically, ovarian tumors frequently had surface involvement consistent with metastasis, but also mimicked a primary tumor with a mixture of benign/borderline/intraepithelial carcinoma-like areas, as well as carcinoma with expansile or destructive stromal invasion. The tubal lesions were predominantly in the form of mucosal colonization without invasion of the underlying structures. Block p16 and high-risk human papillomavirus mRNA signals were not detected in cervical gastric-type adenocarcinomas and ovarian metastatic tumors. We conclude that fallopian tube spread may be associated with ovarian metastasis of cervical gastric-type adenocarcinomas that have bad clinical outcomes. Ovarian involvement may be a part of the aggressive nature of these tumors.

Endometrioid Tubal Intraepithelial Neoplasia and Bilateral Ovarian Microcystic Stromal Tumors Harboring APC Mutations: Report of a Case

Microcystic ovarian tumor of the ovary is a neoplasm of presumed stromal derivation characterized by CTNNB1 or APC alterations leading to nuclear β-catenin expression. This tumor has been described as unilateral and indolent in previously published series. The recently characterized endometrioid tubal intraepithelial neoplasia (eTIN) is an epithelial proliferation of the tube also characterized by nuclear β-catenin staining, and distinct from high-grade serous precursors. Herein, a case of bilateral ovarian microcystic stromal tumors and multiple left tubal eTINs discovered incidentally in a 41-yr-old woman with previous history of colon cancer is described. Both ovarian and tubal proliferations harbored APC inactivating mutations. Although history of familial adenomatous polyposis or a germline defect could not be confirmed, the history of colon cancer at a young age and the shared APC mutation in both microcystic stromal tumor and eTIN were suggestive of this possibility. Microcystic stromal tumor has been described in the setting of familial adenomatous polyposis syndrome. This case adds to this association by documenting for the first time bilateral ovarian involvement by microcystic stromal tumor. Moreover, it alerts to the possibility of endometrioid neoplasia of the fallopian tube secondary to APC mutations, a previously undescribed phenomenon.

Sebaceous Carcinoma Arising in Ovarian Teratoma: First Report Associated With Germline Mismatch Repair Gene Mutation

Sebaceous carcinoma is an uncommon primary cutaneous neoplasm which may be associated with mismatch repair (MMR) abnormalities and sometimes with Muir-Torré syndrome. These neoplasms rarely arise in the ovary within a teratoma/ dermoid cyst. We report a sebaceous carcinoma arising in an ovarian teratoma in a 49-yr old (the 14th case reported in the literature) which exhibited loss of expression of MMR proteins MSH2 and MSH6. A germline mutation c.1102C>T was present in exon 7 of the MSH2 gene, the first report of a germline mutation associated with this tumor type. In reporting this case, we review prior reports of primary ovarian sebaceous carcinoma. We recommend that all sebaceous carcinomas of the ovary undergo immunohistochemistry for MMR proteins for investigation of possible Lynch syndrome.

Well-developed Cerebellum in an Ovarian Mature Teratoma From a Pregnant Female

Teratomas are the most common neoplasm of the ovary, comprising over half of all diagnosed tumors in patients under 50. Most lesions are classified as benign mature teratomas and are histologically defined by the presence of mature tissues from one or more of the embryological germ layers: ectoderm, mesoderm, and endoderm. Neuroectodermal derivatives, including glia, neurons, ependymal cells, and meninges are present in a third to half of mature teratomas. Although teratomatous tissue elements are typically arranged in a haphazard fashion, well-developed and organized embryonic organ structures have been rarely reported and often with limited histologic, clinical, or gross characterization. In this report, we describe the case of an ovarian mature cystic teratoma identified in a pregnant female which exhibited remarkably well-developed posterior fossa structures including lobated and foliated cerebellum with appropriate anatomic organization and associated brainstem, ventricular, and meningeal structures.

Unusual Variants of Teratoma Involving the Gynecologic Tract

Teratomas are tumors of germ cell origin, and in the female genital tract are subclassified as immature or mature based on the presence or absence, respectively, of immature elements. Somatic tumors may also develop in association with teratomas, and most commonly include thyroid tumors, carcinoids and carcinomas. We report herein 2 rare forms of gynecologic teratomas: 1 case of immature teratoma of the uterus and 1 case of a benign follicular hamartoma arising in association with mature cystic teratoma of the ovary.

“Uterine-type” Extra-uterine High-grade Sarcoma of the Rectovaginal Septum: Case Report and Review of Literature

The rectovaginal septum is an unusual location for neoplastic processes. The majority of these are extensions of tumors of the rectum or vagina. Masses arising primarily from the rectovaginal fascia are rare. Most primary rectovaginal malignant neoplasms are carcinomas that arise in the setting of endometriosis. Sarcomas in this location are exceedingly rare, with only few cases reported in the literature. We report a case of a 44-year-old lady who developed a high-grade sarcoma in the rectovaginal septum in the setting of endometriosis. We also discussed the differential diagnosis of this lady’s challenging and unique lesion, which is most probably an extra-uterine “uterine-type” high-grade sarcoma that shows overlapping features of several entities. Moreover, we performed a literature review of sarcomas in this rare location. Given the fact that the rectovaginal septum is a common location for endometriosis, in the case of a rectovaginal neoplasm, a thorough sampling and a careful search for endometriotic lesions are important, as they may be a clue for the diagnosis. Although rare, sarcomas should always be considered in the differential diagnosis of rectovaginal neoplasms.

Large Ovarian Follicle Cyst: Benign Mimic of Cystic Adult Granulosa Cell Tumor

While most ovarian follicle cysts are <8 cm in greatest dimension, much larger follicle cysts (up to 18.5 cm) have been reported. To our knowledge, the FOXL2 mutation status of such cases has not been documented in the literature. Here, we report the features of a 14 cm ovarian cyst with no FOXL2 mutation detected by targeted next-generation sequencing. While adult granulosa cell tumor was the chief entity in our differential diagnosis, the absence of convincing nuclear grooves, lack of architectural variability, presence of a theca layer, and absence of FOXL2 mutation were consistent with a diagnosis of ovarian follicle cyst.

Adenoid Cystic Carcinoma of the Vulva and Vagina: A Clinicopathologic, Immunohistochemical, and Molecular Characterization of Five Cases

Adenoid cystic carcinoma (ACC) is a rare neoplasm most frequently observed in the salivary glands, that can occur in other organs, including the vulva and vagina. Oncogenic mechanisms involving MYB, NFIB, and MYB-NFIB rearrangements have been described, but evidence in the vulva and vagina remains scarce. Our aim is to report the clinicopathologic features, immunohistochemical, and molecular findings in a series of vulvar and vaginal ACCs. Five cases were included. Medical records and slides were reviewed. Formalin-fixed paraffin-embedded material was available in 4 cases, where additional immunohistochemical and molecular studies were carried out. Fluorescence in situ hybridization using MYB, MYBL1, and NFIB bacterial artificial chromosome–clones break-apart and MYB::NFIB BAC-clones fusion probes was performed. The patients’ mean age at diagnosis was 52 years. Tumor size ranged from 0.5 to 5 cm. Microscopic examination revealed tubular, cribriform, and solid patterns. Perineural invasion was seen in 4 cases. Patients were treated with surgery, some with adjuvant radiation therapy. During follow-up (mean: 11 yr), 4 patients developed local recurrences. Recently, one of these patients developed pulmonary disease. Cam 5.2, CK5/6, CD117, and DOG-1 were positive in all 4 cases and S100 and calponin were positive in 3 cases. MYB rearrangement was present in 3 cases, including one with concurrent MYB amplification. There were no MYBL1 or NFIB rearrangements and no MYB::NFIB fusions. Our findings corroborate that the histologic, immunohistochemical, and oncogenic background is similar between ACCs of the lower female genital tract and ACCs elsewhere, although the canonical MYB::NFIB fusion seems to be a less common finding in this location.

PRAME Immunohistochemistry for Distinguishing Vulvar and Vaginal Melanoma From Benign Melanocytic Nevi

Vulvovaginal melanoma (VVM) is a rare but deadly disease, accounting for 5% of all vulvar malignancies, with a 5-yr survival rate of only 47% for all stages of the disease. VVM is a distinct subset of melanoma, with a unique genomic profile and underlying pathogenesis unassociated with sun exposure. Distinguishing these rare malignancies from very common pigmented lesions of the vulva and vagina is challenging as histologic features often overlap between entities. PReferentially expressed Antigen in MElanoma (PRAME) is a melanoma-associated protein, and immunohistochemistry (IHC) for PRAME distinguishes cutaneous, oral mucosal, and retinal melanoma from atypical nevi. Given the biological differences between VVM and cutaneous melanoma, the utility of PRAME IHC for the diagnosis of VVM is unknown. We accrued a cohort of 20 VVM and 21 benign vulvar melanocytic nevi. We found that nuclear PRAME IHC staining with 4+ intensity was present in 85% of the VVM and 0% of the nevi. With the assistance of PRAME IHC, we found evidence of close or positive margin involvement in 3 of 10 cases where margins were originally diagnosed as negative for melanoma in situ. Our study is the first to assess PRAME IHC in a cohort of VVM cases and provides confidence for using PRAME IHC to assist with diagnosis and margin assessment in this rare disease.

Mullerian Polyp of the Vagina: Report of Three Cases of a Previously Undescribed Lesion With Discussion of the Differential Diagnosis

Benign and malignant neoplasms of the vagina are rare. We report 3 primary vaginal polypoid lesions involving the upper or mid-vagina in patients aged 40, 60, and 67 years. The lesions bore a striking morphologic resemblance to benign endocervical or endometrial polyps and we suggest the designation Mullerian polyp of the vagina. As far as we are aware, similar cases have not been reported previously in the literature. Follow-up ranging from 6 to 21 months has been uneventful. In reporting these cases, we discuss the possible origin and differential diagnosis and review vaginal lesions with a benign glandular component.

Primary Ovarian Melanoma Arising From a Mature Teratoma With Melanoma In Situ Present in the Ciliated Columnar and Squamous Epithelium in a Patient With Synchronous Skin Basal Cell Carcinoma

Primary ovarian melanoma arising from ovarian teratomas are rarely reported and difficult to accurately diagnose. Cases in the literature rely on a diagnosis of exclusion, and cases of primary ovarian melanoma with pathologic evidence of melanoma in situ are exceedingly rare. We report a case of a 66-yr-old female who presented to emergency department with abdominal pain and bloating. Computed tomography scan showed a 21 cm complex pelvic mass. An urgent laparoscopic bilateral salpingo-oophorectomy was performed. Pathologically the mass was identified as a mature teratoma. Within the cystic teratoma, there was an area showing a sheet arrangement of atypical cells. Those atypical cells were positive for Melan A, Sox10, HMB45, and c-KIT, and negative for PD-L1. Melanoma in situ was present in both the squamous and ciliated columnar epithelium. The melanoma was negative for PD-L1, and no BRAF (codon 600, exons 11, 14, and 15) or c-KIT (exons 2, 9, 10, 11, 13, 14, 15, 17, 18) mutations were identified, thus supporting the so-called triple negative malignant melanoma. A thorough dermatologic exam was conducted and only a 3 mm skin basal cell carcinoma was confirmed on biopsy. At 11 mo of follow-up, the patient is disease free and doing well and no metastatic melanoma has been identified. To the best of our knowledge, this is the first documented case of a primary ovarian melanoma arising in a mature teratoma with evidence of melanoma in situ present in both ciliated columnar and squamous epithelium in a patient with synchronous skin basal cell carcinoma. Our case is positive for c-KIT protein (CD117) by immunohistochemistry, but negative for KIT mutation. More case reports are needed to further characterize the disease.

Pelvic and Ovarian Recurrence of Small HPV-associated Cervical Adenocarcinoma With Transformation to Neuroendocrine Carcinoma

The phenomenon of small human papillomavirus–associated cervical adenocarcinomas involving the ovary via a transuterine and transtubal route is uncommon but well described in the literature. We report a unique case of a small human papillomavirus–associated cervical adenocarcinoma spreading to both ovaries and the pelvis via this route 22 mo after loop excision and trachelectomy and developing into a high-grade neuroendocrine carcinoma in the metastasis.

A Rare Case of Castleman Disease Presenting as an Ovarian Tumor

Castleman disease (CD) is a rare lymphoproliferative disorder of unknown etiology. Its most common location is the mediastinum, but many other sites have been reported. We report a case of primary CD of the ovary, a rare localization with only 2 cases including the present case described in the world literature to date. A 58-yr-old woman who initially presented with abdominal pain underwent computed tomography scan which showed bilateral well-circumscribed solid adnexal masses. Because an ovarian bilateral tumor was suspected the patient was treated with a hysterectomy and bilateral salpingo-oophorectomy and the histopathologic examination confirmed the diagnosis of CD hyaline-vascular type of the right ovary associated with a contralateral fibroma. Three years after surgery the patient is alive and well and shows no signs of recurrent disease. The occurrence of this rare presentation of CD is the subject of this report. The problems of differential diagnosis with the most frequent lesions of the female pelvis are also discussed.

Krukenberg Tumor of Ovary During Pregnancy: Learning From A Mistake

Sertoli-Leydig cell tumor of the ovary with heterologous differentiation is a relatively uncommon tumor that occurs in females of variable age range. Krukenberg tumor (KT) is a relatively more common tumor of the ovary although only a few cases of KT occur during pregnancy making it an equally uncommon tumor in this setting. We received a unilateral ovarian mass in a 25-yr-old primigravida which we reported as Sertoli-Leydig cell tumor with heterologous (intestinal) differentiation based on its clinical and histomorphologic features. However, on further investigation, a gastric mass was found which was a signet-ring cell adenocarcinoma. We rectified our diagnosis of ovarian mass as KT. We retrospectively analyzed the reasons for our mistake and concluded that the rarity coupled with the nonclassic clinical features and histomorphology of KT during pregnancy pose challenges to the correct diagnosis. This report highlights the diagnostic challenges faced by us along with the ways to circumvent them in the future.

Mitotically Active Cellular Fibroma of the Ovary Recurring After the Longest Interval of Time (16 yr): A Challenging Case With Systematic Literature Review

Cellular fibromas represent ~10% of ovarian fibromas. Mitotically active cellular fibromas show mild nuclear atypia but ≥4 mitoses/10 high-power fields: the clinical course is usually uneventful but literature review is lacking. A 34-yr-old woman underwent left oophorectomy for a 9-cm ovarian mitotically active cellular fibroma at another hospital. The tumor was cellular (spindle cells in fascicular and storiform patterns) revealing mild atypia and 4 nonatypical mitoses/10 high-power fields without necrotic areas. After 16 yr, the tumor recurred as a 5-cm peritoneal nodule on the anterior sigmoid wall near the sigmoid-rectal junction. Frozen section revealed a spindle cell tumor invading the intestinal tunica muscularis propria: a gastrointestinal stromal tumor was favored as previous history was unavailable at that time. Intestinal resection was performed: no residual tumor was found. The patient was followed-up for 8 yr without further recurrences. The peritoneal nodule showed 2 mitoses/10 high-power fields and pericellular reticulin staining. The tumor was variably positive for vimentin/bcl-2/melan-A/CD56/ER/PR/α-inhibin/CD10/calretinin, focally positive for desmin, negative for pan-cytokeratin/actin/EMA/CD34/HMB45/CD117/CD99/S100/synaptophysin. The Ki67-index was ~9%. To our systematic literature review, 7 additional recurrent cases were reported. We describe a mitotically active cellular fibroma recurring after the longest interval of time. Extensive sampling of difficult cases should exclude malignant areas. Moderate nuclear atypia, tumor rupture, adhesions to pelvic/abdominal organs, infarction with extraovarian involvement, and incomplete excision may lead to relapse but there are conflicting data: prolonged follow-up can be suggested in these cases.

Follicle Cysts of the Ovary: A Report of 30 Cases of a Common Benign Lesion Emphasizing its Unusual Clinical and Pathologic Aspects

The common ovarian follicle cyst is typically straightforward from both clinical and pathologic perspectives, but may have a variety of unusual features from both aspects at various stages of life. Lack of familiarity with these may lead to diagnostic quandaries, the most common of which is distinguishing between a follicle cyst and cystic granulosa cell tumor of either adult or juvenile type. We reviewed 30 cases of follicle cysts, all sent in consultation, to highlight unusual aspects of a common lesion. Patients ranged from 3 d to 47 yr old. Clinical presentations included precocious puberty, pelvic pain, or an incidentally discovered pelvic mass, including those occurring in neonates and in 2 adults with pituitary adenomas, one of which was diagnosed 3 yr after presentation with the ovarian cyst. Size ranged from 0.5 cm (deflated) to 18.5 cm, with 7 exceeding 8 cm in greatest dimension. Twelve cases demonstrated small satellite cystic follicles in the wall of the dominant cyst. The granulosa cell layer varied in thickness and mitotic activity (which ranged from 1 to 36 per 10 HPF), but uniformly displayed round nuclei that lacked nuclear grooves. Luteinization of the granulosa cell layer, theca layer, or both was seen across all clinical scenarios, with unluteinized cysts being most common in precocious puberty patients. This series documents that although typically smaller, a subset of follicle cysts are the same size as cystic granulosa cell tumors and the 2 entities may be grossly indistinguishable. Helpful clues to the diagnosis of follicle cyst are the lack of nuclear grooves (vs. adult granulosa cell tumor) and lack of invagination of granulosa cells into the cyst wall (vs. both forms of granulosa cell tumor). Mitoses in the granulosa cells are of no aid in the differential with either form of granulosa cell tumor as follicle cysts may exhibit brisk mitotic activity. Our series highlights some of the unusual clinical aspects, one relatively well known—an association with isosexual precocity, but 2 not as widely known, those occurring in neonates and those due to a pituitary adenoma, the latter sometimes not being discovered until a few years after presentation with a follicle cyst.

Benign Brenner Tumor in an Ectopic Ovary: A Case Report and Review of Literature

Supernumerary ectopic ovaries are very rare, with fewer than 40 cases of isolated supernumerary ovaries reported in the literature since their discovery in 1864. Tumors arising in ectopic ovaries are also extremely rare, with only a handful of reports in the literature. Given the rarity of this combination of findings, we report a case of a 68-yr-old woman incidentally found to have a 4.7 cm solid retroperitoneal mass adjacent to the liver, diagnosed as a benign Brenner tumor arising in a supernumerary ectopic ovary. To our knowledge, there has been only one previously reported case of Brenner tumor arising in this unusual setting.

Late Development of Metastatic Ovarian Mucinous Adenocarcinoma From Primary Gallblader Adenocarcinoma and High-grade Dysplasia

The ovary is a common site of metastatic mucinous adenocarcinoma. In most, but not all, cases the presence of a primary neoplasm elsewhere is already known and the metastasis is picked up at diagnosis or is discovered a relatively short time following the diagnosis of the primary neoplasm. We report 2 cases of metastatic gallbladder adenocarcinoma involving the ovaries of women aged 65 and 59 after long time periods of 8 and 5 yr following diagnosis of high-grade dysplasia or early adenocarcinoma of the gallbladder, respectively. In both cases, a review of the original operative notes suggested the possibility of intraoperative gallbladder rupture or bile leakage suggesting that the metastatic disease may have developed secondary to “seeding.” In both cases, p53 immunohistochemistry revealed identical null mutation-type immunoreactivity within the gallbladder and ovarian neoplasms, assisting in confirming the ovarian disease as a metastasis from the gallbladder. The possibility of late ovarian metastasis of gallbladder dysplasia or adenocarcinoma secondary to rupture/bile leakage should be borne in mind.

Diffuse Intratumoral Stromal Inflammation in Ovarian Clear Cell Carcinoma is Associated With Loss of Mismatch Repair Protein and High PD-L1 Expression

Ovarian clear cell carcinoma (OCCC) is an aggressive chemotherapy-resistant cancer with limited treatment options, and some OCCCs have mismatch repair (MMR) deficiency (MMRD). Emerging evidence has revealed that various cancers with MMRD are susceptible to anti-programmed death-1/programmed death ligand-1 (anti-PD-1/PD-L1) immunotherapy, and certain histologic features are associated with MMRD. However, few studies have addressed this in OCCC. We reviewed 76 OCCCs for tumor-associated inflammation (intratumoral stromal inflammation and peritumoral lymphocytes) and performed immunohistochemistry for 4 MMR proteins and PD-L1. MMR-deficient OCCCs were analyzed for microsatellite instability (MSI), and those with MLH1 loss were tested for MLH1 promoter methylation. No patients fulfilled the Amsterdam II criteria for the diagnosis of Lynch syndrome. Four (5.3%) tumors showed diffuse intratumoral stromal inflammation obliterating the tumor-stroma interfaces, and none had peritumoral lymphoid aggregates. MMRD was found in 2 (2.6%) tumors; one had MLH1/PMS2 loss (MSI-high and MLH1 promoter methylation was detected) and the other had MSH2/MSH6 loss (MSI-low). Twenty (26.3%) tumors showed tumoral PD-L1 expression ≥1%. Both MMR-deficient tumors showed diffuse intratumoral stromal inflammation and tumoral PD-L1 expression ≥50%. Three of the 4 (75%) tumors with diffuse intratumoral stromal inflammation also showed tumoral PD-L1 expression ≥50%. None of the tumors without diffuse intratumoral stromal inflammation showed MMRD (P=0.021) or tumoral PD-L1 expression ≥50% (P=0.0001). We identified a strong correlation among diffuse intratumoral stromal inflammation, MMRD, and high tumoral PD-L1 expression in a small but significant subset of OCCCs. Histologic evaluation can facilitate patient selection for subsequent anti-PD-1/PD-L1 immunotherapy.

Expression of HER2 and EGFR Proteins in Advanced Stage High-grade Serous Ovarian Tumors Show Mutual Exclusivity

Human epidermal growth factors play an important role in ovarian carcinogenesis and are evaluated for prognostic and possible therapeutic roles in high-grade serous ovarian malignancies. The present study was undertaken to evaluate the expression of human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR) in advanced stage serous carcinoma and their influence on prognosis. The expression of HER2 and EGFR was studied in 59 cases of stage III and IV ovarian serous carcinomas by immunohistochemistry and fluorescent in situ hybridization. Of the 48 interpretable tumors for HER2, 6 tumors (12.5%) were scored as positive, 14 (29%) as equivocal and 28 tumors (58.5%) were negative by immunohistochemistry, while only 2/48 (4%) showed frank amplification by fluorescent in situ hybridization with ≥4 copies per cell. HER2 gene expression measured by quantitative polymerase chain reaction had good positive correlation with both protein expression and gene amplification. Although EGFR expression was seen in 32% of tumors, none of the tumors positive for HER2 protein or gene amplification had co-expression of EGFR indicating mutual exclusivity of their expression. Gene expression of both proteins also confirmed their inverse correlation (Pearsons CC=−0.15, P=0.3). Further there was no influence of protein or gene expression of these markers on the overall survival. In conclusion, HER2 and EGFR are expressed in a small percentage of tumors and the mutual exclusivity of these markers precludes the possibility of dual targeting with anti-HER2 and anti-EGFR therapy in advanced stage high-grade serous ovarian carcinoma.

Pure Primary Ovarian Carcinoid Tumor

Primary ovarian carcinoid tumors are uncommon neoplasms that typically arise in the context of a mature cystic teratoma. Pure primary ovarian carcinoid tumors (PPOCTs) are rare and present as a solid ovarian mass in which, by definition, elements of an associated teratoma or other neoplasm are absent. We report a case of a middle-aged woman who presented with abdominal distension. Computed tomography identified a 20 cm abdominopelvic mass. The patient underwent exploratory laparotomy, hysterectomy, and bilateral salpingo-oophorectomy. A large, solid, yellow-tan ovarian mass was resected and diagnosed as a PPOCT. Para-aortic lymph node metastases were identified. This case highlights the gross and microscopic findings characteristic of PPOCTs. In addition, the large number of differential considerations for an insular PPOCT at intraoperative evaluation are discussed.

The “Far Left” of the Morphologic Spectrum of Ovarian High-grade Serous Carcinoma: Case Report of a Purely Noninvasive High-grade Serous Carcinoma Mimicking an Ovarian Serous Borderline Tumor

High-grade serous carcinoma has a variety of different growth patterns, but is typically easily recognizable to pathologists and rarely confused with serous borderline tumors. We report a case of a 71-yr-old woman with a unilateral 5.1 cm ovarian cyst with small papillary projections on contrast-enhanced magnetic resonance imaging of the pelvis. Histologic examination showed a noninvasive papillary neoplasm with hierarchical branching and epithelial proliferation, and thus, at low magnification, bearing a striking resemblance to a serous borderline tumor. However, a more careful examination demonstrated high-grade cytologic features, nuclear pleomorphism, and abundant mitotic activity, suggestive of high-grade serous carcinoma. The morphology and immunohistochemical profile of this lesion is consistent with a rare, purely noninvasive growth pattern of high-grade serous carcinoma. This lesion represents the “far left” of the high-grade ovarian serous carcinoma morphologic spectrum and can mimic a serous borderline tumor.

Clear Cell Papillary Cystadenoma of the Ovary Masquerading as Metastatic Clear Cell Renal Cell Carcinoma: A Case Report and Review of the Literature

Clear cell papillary cystadenoma of the epididymis is an uncommon benign neoplasm, usually seen in patients with von Hippel-Lindau disease. Morphologic and immunohistochemical examination aid in distinguishing clear cell papillary cystadenoma from malignant histologic mimics including low-grade mesothelial proliferations and metastatic clear cell renal cell carcinomas. Analogous lesions have been described in the female genital tract, often posing diagnostic challenges due to their low incidence. Here, we present the difficult diagnostic aspects of the first case of clear cell papillary cystadenoma involving the ovary, including the salient immunohistochemical, ultrastructural, and molecular characteristics.

Stromal Endocrine Cell Micronests Associated With an Ovarian Mucinous Cystadenoma: Endocrine Cell Preservation (Pseudohyperplasia) Potentially Mimicking Stromal Sex Cord Proliferation or Tumor Microinvasion

Endocrine cell micronests (ECMs) have been described only twice previously in the ovary, both in association with mucinous neoplasms exhibiting intraepithelial endocrine cell hyperplasia. We report a 31-yr-old patient with a mucinous cystadenoma in which ECMs were distributed in the stroma surrounding degenerate glandular elements. Immunohistochemistry demonstrated only sparse endocrine cells within the neoplastic glands. We postulate that the ECMs in this case reflected relative preservation of endocrine elements in the context of epithelial atrophy, a process more commonly encountered in gastrointestinal pathology. Ovarian ECMs should also be distinguished from stromal sex cord proliferations and tumor microinvasion.

“Neuroendocrine Tumor Grade 3 (NET G3)” of the Uterine Cervix: A Report of 2 Cases

In the fifth edition of the World Health Organization classification of female genital tumors, neuroendocrine neoplasms are subcategorized as neuroendocrine tumors (NETs) of grade 1 (G1) and G2, and neuroendocrine carcinoma. NET G3 is not included, as it is for classification of pancreas tumors. Herein, we report 2 cases of “NET G3” of the uterine cervix with long-term follow-up. The patients are 40- and 36-yr-old women who presented with polypoid masses on the uterine cervix. Microscopic examination of hysterectomy specimens revealed tumor features similar to those of pancreatic NET G3 and intestinal type mucinous carcinoma cells invading the cervical stroma. In both cases, the NET component was positive for synaptophysin and chromogranin A, and negative for TTF-1. Mitotic counts were <1/2 mm2 and 5/2 mm2, and the Ki-67 labeling indexes were 57% and 39%, respectively. Pathologic stage classifications (AJCC, version 9) were pT1b1, pN0, and cM0 (FIGO stage IB1), and both patients received adjuvant therapy. One patient had lung and pancreas metastases 4 to 8 yr after initial surgery, which were surgically removed. Both patients remain alive without evidence of recurrent disease 6 and 16 yr after initial surgery. The indolent clinical courses of these cases appear to indicate that cervical “NET G3” is biologically closer to NET than neuroendocrine carcinoma; thus, including uterine cervical “NET G3” in the classification may be justified. However, the optimal management for this tumor type remains undetermined.

PTEN Loss and ARID1A Mutation in an HPV-positive Metastatic Adenocarcinoma Diagnosed Almost 18 yr After an Intact Cone Excision for Endocervical Adenocarcinoma In Situ

There have been previous reports of neoplasms with the morphology of endocervical adenocarcinoma in situ (AIS) that secondarily involve the ovaries, presumably through transtubal spread, with a smaller subset metastasizing to distant sites. These ovarian metastases have been discovered up to 7 yr postexcision of the endocervical lesion, consistent with the known potential for overtly invasive cervical carcinomas to recur late after primary curative management. Herein, we present a case of a premenopausal woman with a pelvic mass classified as metastatic human papillomavirus (HPV)-associated endocervical adenocarcinoma (p16-block immunoreactive, high-risk HPV positive by in situ hybridization with PTEN loss, ARID1A, and PBRM1 mutations detected by qualitative next-generation sequencing), identified 17.7 yr (212 mo) after a fertility-sparing cone excision with negative margins for endocervical AIS [HPV-associated, p16-block immunoreactive; PTEN, and BAF250a (ARID1a) expression retained]. Our case highlights: (1) the potential for a subset of lesions with the morphology of AIS to metastasize, and the extraordinarily long timeframe (almost 18 y, the longest reported to date) during which metastases may still be identified; (2) alterations in PTEN and ARID1A may play a role in the progression of a subset of endocervical carcinomas; and (3) the need for studies to evaluate the utility of incorporating ovarian/pelvic imaging into surveillance protocols following fertility-sparing excisions or ovarian-preserving hysterectomies, during the management of endocervical adenocarcinomas, as well as the need to counsel patients about the small but real risk of delayed discovery of ovarian metastases following fertility-preserving surgeries for AIS.

Papillary Squamous Cell Carcinoma of the Uterine Cervix: Biopsy Samples Frequently Underrepresent the Presence of Stromal Invasion

Papillary squamous cell carcinoma is a rare variant of squamous cell carcinoma, histologically characterized by thin or broad papillae lined by epithelium showing the features of high-grade squamous intraepithelial lesion. Given the exophytic nature of these neoplasms, the diagnosis, assessment and quantification of invasion may be difficult in small biopsies. The goal of this study was to determine the presence and extent of cervical stromal invasion by comparing biopsy samples with excisional specimens in a cohort of patients diagnosed with papillary squamous cell carcinoma. Cases were identified from the surgical pathology files between the years 2003 and 2018 and only cases in which the patients underwent an excisional procedure following the diagnostic biopsy were included. Eighteen cases were identified. Patients age ranged 21 to 72 yr (mean: 46.2 yr). Review of the initial, presurgical biopsies showed that 17/18 (94%) patients had no evidence of stromal invasion. In the surgical excision specimens (2 cone biopsies, 1 loop electrosurgical excision procedure, and 15 hysterectomies), 13 cases (76.5%) showed invasive squamous cell carcinoma. Tumor sizes ranged 1.0 to 6.1 cm; stromal invasion ranged in depth 0.2 to 2.2 cm (median: 1.2), and in horizontal length 0.3 to 4.0 cm (median: 2.01). Papillary squamous cell carcinoma is a rare variant of squamous cell carcinoma of the cervix that may impose some diagnostic difficulties in small biopsies. Our findings demonstrated that the significant majority of cases might only show the presence of invasive cancer in excisional samples. Awareness of this data is important to guide proper management and avoid under-treatment.

PD-L1 Interpretation in Cervical Carcinomas: Proceedings of the ISGyP Companion Society Session at the 2020 USCAP Annual Meeting

Primary Synovial Sarcoma of the Uterine Cervix: First Case Report

Synovial sarcoma is a translocation associated soft tissue malignancy frequently affecting young adults. The classic translocation is t(X;18)(p11.2;q11.2): SS18-SSX1/2/4 fusion. Synovial sarcoma tends to favor the distal extremities but can also arise in other locations. To date, no case of primary synovial sarcoma of the uterine cervix has been reported. We report a 42-yr-old woman with no prior history who presented to clinic with vaginal spotting for 3 mo and was found to have a large mass in the uterine cervix. The mass was evacuated from the vagina and sent for pathologic diagnosis. Sections showed proliferation of monotonous spindle cells with scant eosinophilic cytoplasm, round to slightly irregular nuclei, variable nucleoli and frequent mitosis in a background of delicate capillary and occasional thick-walled vessels. No malignant epithelium was identified in the entire specimen. On immunohistochemical workup tumor cells were negative for pan cytokeratin, OSCAR, EMA, chromogranin, S100, SMA, desmin, myogenin, WT1, CD117, CD34, and BRG1. CD45 was positive in a few inflammatory cells. Cyclin D1 showed partial weak to moderate nuclear reactivity. CD99 demonstrated strong diffuse membranous reactivity and BCL-2 showed strong cytoplasmic staining in 60% of tumor cells. Florescence in situ hybridization results for EWSR1, BCOR, and CIC gene rearrangements were negative, however, florescence in situ hybridization results for SS18 (SYT) (18q11) gene rearrangement was positive. A diagnosis of monophasic synovial sarcoma was rendered. We review the differential diagnoses of tumors with similar morphology and discuss the diagnostic process. With this case report it is imperative to include synovial sarcoma in differential diagnosis list of sarcomas of uterus and cervix.

The Value of DICER1 Mutation Analysis in “Subtle” Diagnostically Challenging Embryonal Rhabdomyosarcomas of the Uterine Cervix

Embryonal rhabdomyosarcoma of the uterine cervix is a rare neoplasm which is almost invariably associated with pathogenic somatic or germline DICER1 mutations; patients with germline mutations have DICER1 syndrome. We report 2 subtle cervical embryonal rhabdomyosarcoma, one occurring in a 21-yr-old woman with a known history of DICER1 syndrome and the other in a 19-yr-old woman with no history of DICER1 syndrome or DICER1-associated neoplasms. Both neoplasms focally involved otherwise benign endocervical polyps and were characterized histologically by subtle areas of increased stromal cellularity, nuclear atypia and mitotic activity; there was focal nuclear staining of these areas with the skeletal muscle markers myogenin and myoD1. In both cases, demonstration of a somatic DICER1 RNase IIIb mutation in the tumor was instrumental in establishing the diagnosis. We believe these neoplasms represent the earliest discernible phase of cervical embryonal rhabdomyosarcoma. Pathologists should have a high index of suspicion when atypical stromal elements are present in endocervical polyps and immunohistochemistry together with DICER1 sequencing will assist in diagnosis.

Skene’s Gland Derivatives in the Female Genital Tract and Cervical Adenoid Basal Carcinoma are Consistently Positive With Prostatic Marker NKX3.1

Cervical ectopic prostatic tissue and vaginal tubulosquamous polyp are rare lesions which exhibit variable, and often focal, immunohistochemical expression with traditional prostatic markers [prostate-specific antigen and prostatic acid phosphatase (PSAP)]. These lesions are thought to arise from periurethral Skene’s glands, the female equivalent of prostatic glands in the male. Adenoid basal carcinoma is a rare and indolent cervical neoplasm. Expression of the prostatic marker NKX3.1 in ectopic prostatic tissue and tubulosquamous polyp has been reported but no studies have examined immunoreactivity with this marker in adenoid basal carcinoma. We stained 19 cases [adenoid basal carcinoma (n=6), cervical ectopic prostatic tissue (n=11), and vaginal tubulosquamous polyp (n=3); 1 case contained both adenoid basal carcinoma and ectopic prostatic tissue] with NKX3.1. In all cases, the glandular component of these lesions exhibited diffuse nuclear immunoreactivity while normal endocervical glands were negative. Prostate-specific antigen was positive in 4 of 9 and 0 of 3 cases of ectopic prostatic tissue and tubulosquamous polyp, respectively, while PSAP was positive in 3 of 4 and 2 of 2 cases of ectopic prostatic tissue and tubulosquamous polyp respectively; 3 of 5 cases of adenoid basal carcinoma tested were focally positive with PSAP and all 5 were negative with prostate-specific antigen. While the specificity of NKX3.1 should be investigated in future studies, positivity with this marker may be useful in diagnosing these uncommon lesions. NKX3.1 appears a more sensitive marker of ectopic prostatic tissue and tubulosquamous polyp than traditional prostatic markers and positive staining provides further support that these lesions exhibit “prostatic” differentiation and are of Skene’s gland origin. NKX3.1 and PSAP positivity in adenoid basal carcinoma raises the possibility of an association with benign glandular lesions exhibiting prostatic differentiation and we critically discuss the possible association.

A Novel Ciliated, Mucin-producing Variant of HPV-related Cervical Adenosquamous Carcinoma In Situ: A Case Report

Uterine cervical adenosquamous carcinoma in situ was originally defined as having either a uniform population of cells with features intermediate in appearance between glandular and squamous cells, or a mixture of distinct glandular and squamous components within a single lesion. The former type would likely be reclassified today as stratified mucin-producing intraepithelial lesion, while the latter type is vanishingly rare. Here, we report a novel case of bona fide adenosquamous carcinoma in situ, which exhibits 2 morphologically and immunophenotypically distinct components: (1) an inner glandular component composed of a single layer of p40-negative, ciliated, mucin-producing dysplastic columnar cells and (2) an outer p40-positive, stratified dysplastic squamous component otherwise identical to cervical intraepithelial neoplasia-3. Both components show block-positive staining for p16 and are positive for high-risk human papillomavirus RNA by in situ hybridization. Our finding expands the histological spectrum of human papillomavirus–associated preinvasive cervical lesions while also providing further evidence that human papillomavirus–driven processes can exhibit ciliated morphology.

Cervical Superficially Invasive Squamous Cell Carcinoma With Supraclavicular Lymph Node Metastasis: A Case Report

Typically, local spread and lymph-vascular space invasion (LVSI) occur before lymph node (LN) and distant metastases during the progression of uterine cervical cancer. The prognostic value of LVSI in cervical superficially invasive squamous cell carcinoma (SISCC) is still debated. We encountered a rare case of cervical SISCC without LVSI presenting with multiple LN metastases, including pelvic, para-aortic, and left supraclavicular LNs. Immunohistochemical analysis of p16INK4a and in situ hybridization of human papillomavirus confirmed the relationship of the cervical SISCC and pelvic LN metastases. Aspiration cytology of the left supraclavicular LN showed squamous cell carcinoma and our final diagnosis was uterine cervical squamous cell carcinoma, stage IVB. The patient underwent adjuvant chemotherapy. Although relapse was observed at the vaginal stump and in pelvic and para-aortic LNs, chemotherapy and radiotherapy were effective. The patient is alive without disease 40 mo after initial treatment. This is the first case report of cervical SISCC without LVSI presenting with supraclavicular LN metastasis, which contributes to our understanding of the value of LVSI. Immunohistochemical analysis of p16INK4a and in situ hybridization of human papillomavirus were useful in confirming the relationship of cervical SISCC and its metastases. As cervical SISCC with LN metastasis is rare, multi-institutional joint research is needed to clarify its prognosis and appropriate treatment.

Trefoil Factor 2 (TFF2) as a Surrogate Marker for Endocervical Gastric-type Carcinoma

Gastric-type carcinoma (GAS) is the most common human papilloma virus–independent endocervical adenocarcinoma (ECA), characterized by an aggressive behavior. Trefoil factor 2 (TFF2) is a mucin-associated peptide expressed in normal gastric but not endocervical glands. This study was carried out to investigate whether TFF2 could be a surrogate marker to separate GAS from other types of ECA. ECAs from 9 international institutions were reviewed for consensus histotype. Of them, expression of TFF2 was immunohistochemically examined compared with that of HIK1083, using whole sections of 50 ECAs (10 GASs and 40 non-GASs) and 179 ECAs (24 GASs and 155 non-GASs) with tissue microarrays (TMAs). TMAs were assessed to simulate assessment of immunohistochemical stains in small biopsies. Both markers were similarly scored, and any cytoplasmic/membranous staining of >5% of tumor cells was considered positive. Of 50 ECAs with whole sections, TFF2 was significantly more frequently expressed in GASs (8/10) compared with non-GASs (5/40) (P<0.01). In 179 ECAs with TMAs, TFF2 was also significantly more frequently expressed in GASs (7/24) compared with non-GASs (4/155) (P<0.01). There was no significant difference in specificity among the 2 markers. Double positivity for TFF2 and HIK1083 in ECAs was highly specific in separating GASs from non-GAS (P<0.01). A significantly smaller percentage of GASs were TFF2 positive in TMAs than in whole sections (P<0.01). Our results suggest that TFF2 is a promising marker, along with HIK1083, to confirm a diagnosis of GAS. This marker may be negative in small biopsies, indicating the necessity of using other exclusionary markers in combination with rigorous morphologic review and extensive sampling in resection specimens.

The Combination of Transient Receptor Potential Vanilloid Type 1 (TRPV1) and Phosphatase and Tension Homolog (PTEN) is an Effective Prognostic Biomarker in Cervical Cancer

Transient receptor potential vanilloid type 1 (TRPV1) has been reported to play an important role in human cancers. However, the knowledge about TRPV1 in cervical cancer is sparse. Therefore, we evaluated the expression and clinical significance of TRPV1 in cervical cancer. Immunohistochemical analyses were performed for TRPV1 and phosphatase and tension homolog (PTEN) to delineate clinical significance using 150 cervical cancers, 230 cervical intraepithelial neoplasias, and 312 normal cervical epithelial tissues in a tissue microarray. Furthermore, the role of TRPV1 in cell growth was assessed in a cervical cancer cell line. The TRPV1 expression was significantly higher in cervical cancer tissues than in cervical intraepithelial neoplasias, and normal epithelial tissues (P<0.001). In cervical cancer tissues, TRPV1 expression negatively correlated with PTEN expression (Spearman ρ=−0.121, P=0.009). Multivariate survival analysis revealed high TRPV1 expression (hazard ratio=3.41, 95% confidence interval: 1.25–9.27, P=0.016) as an independent prognostic factor for overall survival. Notably. the high TRPV1/low PTEN expression showed the highest hazard ratio (5.87; 95% confidence interval: 2.18–15.82, P<0.001) for overall survival. In vitro results demonstrated that the overexpression of TRPV1 was associated with increased cell viability and colony formation. Overexpression of TRPV1 could be a good biomarker for the prediction of chemoradiation response. Our result suggested promising potential of high TRPV1/low PTEN as prognostic and survival makers. The possible link between the biologic function of TRPV1 and PTEN in cervical cancer warrants further studies.

Squamous Intraepithelial Lesions of the Uterine Cervix The Long and Winding Road of Our Understanding of Their Morphology, Biology, and the Terminology That Describes Them—From First to LAST

Villoglandular Pattern in HPV-associated Endocervical Adenocarcinoma is Associated With Excellent Prognosis: A Reappraisal of 31 Cases Using IECC and Silva Pattern Classification

Villoglandular adenocarcinoma of the cervix is a rare histologic entity that typically develops in young women, characterized by an association with oral contraceptives and excellent prognosis, though this point is controversial. These tumors have not been studied in the context of the International Endocervical Adenocarcinoma Criteria and Classification (IECC) or Silva Pattern Classification. We analyzed 31 cases that met strict diagnostic criteria, including being completely excised with negative margins. These were categorized according to IECC and Silva Pattern Classification and the association with various pathologic parameters analyzed. Most patients were young with a mean age of 41.1 (range 25–79). There were 14 (45.2%) pattern A, 11 (35.5%) pattern B, and 6 (19.3%) pattern C cases. Only 1 of 22 patients (4.5%) presented with lymph node metastasis at the time of diagnosis (pattern C, stage IB1) and 3 (9.7%) had lymphovascular invasion (2 pattern C, 1 pattern B). Overall survival was 100%, while recurrence-free survival was 96.2% for the entire cohort with only 1 case (3.2%) recurring 25 mo after surgery (IB2, pattern B). Kaplan Meier analysis (log rank test) revealed no significant correlation for recurrence-free survival at 5 and 10 yr associated with depth of invasion, tumor size, Silva pattern, FIGO stage, lymphovascular invasion, or lymph node metastasis. Cox univariate analysis demonstrated no independent prognostic factors predicting recurrence-free survival. These results indicate that completely excised villoglandular adenocarcinoma generally has an excellent prognosis and when Silva Pattern Classification is applied, those tumors that potentially have a higher chance for adverse outcomes can be identified.

Dataset for the Reporting of Carcinoma of the Cervix: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

Cervical carcinoma remains one of the most common cancers affecting women worldwide, despite effective screening programs being implemented in many countries for several decades. The International Collaboration on Cancer Reporting (ICCR) dataset for cervical carcinoma was first developed in 2017 with the aim of developing evidence-based standardized, consistent and comprehensive surgical pathology reports for resection specimens. This 4th edition update to the ICCR dataset on cervical cancer was undertaken to incorporate major changes based upon the updated International Federation of Obstetricians and Gynecologists (FIGO) staging for carcinoma of the cervix published in 2018 and the 5th Edition World Health Organization (WHO) Classification of Female Genital Tumors published in 2020 and other significant developments in pathologic aspects of cervical cancer. This updated dataset was developed by a panel of expert gynecological pathologists and an expert gynecological oncologist, with a period of open consultation. The revised dataset includes “core” and “noncore” elements to be reported; these are accompanied by detailed explanatory notes and references providing the rationale for the updates. Standardized reporting using datasets such as this helps facilitate consistency and accuracy, data collection across different sites and comparison of epidemiological and pathologic parameters for quality and research purposes.

Cervical Pleuropulmonary Blastoma-like Tumor Associated With DICER1 and TP53 Mutations

We describe a very unusual cervical tumor in a 12-yr-old patient with a clinical history indicative of DICER1 syndrome. Morphologic, immunohistochemical, and molecular genetic analysis together helped to diagnose this lesion as a cervical pleuropulmonary blastoma-like tumor, associated with TP53 and DICER1 mutations. The tumor displayed usual histologic features including mixtures of embryonal rhabdomyosarcoma, sarcomatous cartilage, compact blastema, primitive spindle cells and anaplasia, akin to type III pleuropulmonary blastoma, and trabecular and retiform patterns. In addition to expanding the phenotypic spectrum of DICER1-associated conditions, we draw attention to genotype-phenotype correlations in DICER1-associated tumors, particularly as they relate to the discovery of a heritable tumor predisposition syndrome.

Yolk Sac Tumor Originating From Cervical Adenocarcinoma: A Case Predominated by Enteroblastic Differentiation

The fetal gut-like phenotype can be found in yolk sac tumors and adenocarcinomas with enteroblastic differentiation (AEBDs). We report a cervical yolk sac tumor in a 44-yr-old woman. The tumor has similar morphology, immunophenotype, and molecular features to the AEBD of the digestive system. The tumor showed a glandular-predominant growth pattern, composed of columnar cells with clear glycogen-rich cytoplasm. The microcystic/reticular architecture or Schiller-Duval bodies were not found in the tumor. Immunohistochemically, the tumor cells were positive for p16, glypican-3 (GPC3), spalt-like transcription factor 4 (SALL4), CDX-2, and p53. TP53 mutation was identified by next-generation sequencing, and human papillomavirus (HPV) 35 was detected by HPV DNA polymerase chain reaction. In the present case, the adenocarcinoma cells in the superficial cervical glandular epithelium and the nonclear glandular components proved the existence of somatic components. The positivity of p16 and HPV also supports that the present case originates from an HPV-associated adenocarcinoma. The yolk sac tumor should be thought of as “germ cell differentiation” from a somatic carcinoma. This kind of yolk sac tumor arising from somatic-type adenocarcinoma in the female genital tract may be the counterpart of AEBD in the digestive tracts and adenocarcinomas with fetal gut-like morphology in other organs. The tumor might be more aggressive than conventional adenocarcinoma, pathologists should highlight the existence of the enteroblastic component in the pathologic report.

Epstein-Barr Virus-positive Mucocutanous Ulcer of the Uterine Cervix: Report of a Rare and Evolving Entity

Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) is a newly described lymphoproliferative lesion characterized by the proliferation of EBV-positive atypical B cells in a variable inflammatory background associated with mucosal or cutaneous ulcers. Commonly involved sites include the oropharyngeal tract, skin, and gastrointestinal tract, with emerging reports describing EBVMCU of genitalia. To date, no lesions have been described of the uterine cervix. Herein, we report the first cervical EBVMCU incidentally discovered at large loop excision of the transformation zone performed for treating human papillomavirus induced high-grade squamous intraepithelial lesion. The patient was a 35-yr-old, human immunodeficiency virus-positive woman with a history of pulmonary tuberculosis. Histologic and immunohistochemical findings showed classic Hodgkin lymphoma-like features. Systemic lymphoproliferative disease was excluded by appropriate clinical and imaging modalities. This case report highlights the prototypical histologic features of cervical EBVMCU. We emphasize the importance of clinicopathologic correlation to avoid overtreatment of a lesion that can otherwise meet histologic criteria for a lymphoma. Clinicians and pathologists should familiarize themselves with this entity, as this indolent, pseudomaligant lesion typically occurs in immunocompromised patients and spontaneously regresses when the cause for the immunosuppression is addressed.

Ciliated Carcinoma of the Endometrium

We report a case of ciliated carcinoma of the endometrium in a 55-yr-old woman with stromal hyperthecosis of the ovaries. The patient presented with postmenopausal uterine bleeding and an endometrial curetting revealed an atypical epithelial proliferation that met the criteria for endometrioid adenocarcinoma notwithstanding an abundance of ciliated cells. Cilia were present not only within typical endometrioid glands but also within microacini of quasi-solid areas as well as inside intracytoplasmic vacuoles. The subsequent hysterectomy specimen demonstrated a well-differentiated adenocarcinoma of the endometrium with a predominance of neoplastic glands lined by ciliated epithelial cells, thus confirming the initial suspicion for ciliated carcinoma. Since the first description of ciliated adenocarcinoma of the endometrium in 1983, only a handful of additional cases have been reported in the literature. We review the spectrum of histologic presentations of this endometrial neoplasm and elaborate on its distinction from cilia-bearing mimickers and its histogenesis.

The Expression of HPV E6/E7 mRNA In Situ Hybridization in HPV Typing-negative Cervical Cancer

High-risk human papillomavirus (HPV) persistent infection is the major tumorigenesis factor for cervical cancer (CC). However, the incidence of HPV-negative CC is 5% to 30% with different HPV detection methods. High-risk HPV E6/E7 mRNA in situ hybridization (RISH) can detect HPV-driven tumors. Our study aimed to explore whether HPV typing-negative CC was caused by HPV infection. The tissues of CC patients with HPV typing results, collected from cervical biopsies, conization, or hysterectomies, were submitted to RISH using RNAscope chromogenicin. Immunohistochemistry was performed to evaluate the expression of p16INK4a and Ki-67. A total of 308 women with HPV typing results were enrolled, and 30 (9.74%) cases of HPV typing were negative. In HPV typing-negative CCs, 28/30 (93.3%) were positive for RISH, which contained 22/22 (100%) squamous cell carcinomas and 6/8 (75%) adenocarcinomas. RISH was positive in 278/278 (100%) HPV typing-positive CCs, which included 232/232 (100%) squamous cell carcinomas and 46/46 (100%) adenocarcinomas. Positive RISH in HPV typing-negative CC was significantly lower than in the HPV typing-positive group (P=0.002, 95% confidence interval: 0.848–1.027). However, this significant difference only existed in adenocarcinoma. No significant differences were seen in the expression of p16INK4a and Ki-67 (all P>0.05). HPV typing may cause misdiagnosis in 9.74% of CC patients, and HPV E6/E7 mRNA can detect HPV in CC with HPV typing-negative patients. This approach could provide a novel option to accurately detect high-risk HPVs in cervical tumors and help to eliminate the percentage of misdiagnosed HPV-related cases.

Clear Cell Adenocarcinoma In Situ as a Potential Precursor Lesion for Sporadic Invasive Endocervical Clear Cell Adenocarcinoma

Low-grade Neuroendocrine Tumor of the Cervix: Report of 3 Cases of a Rare Neoplasm With Review of the Literature

Neuroendocrine neoplasms are uncommon in the cervix with almost all representing neuroendocrine carcinomas (NECs), either small cell or large cell type. Cervical low-grade neuroendocrine tumors (NETs) are extremely rare with few recent reports using contemporary modern diagnostic criteria. We report 3 cases of cervical NET in patients aged 32 to 57 yr and undertake a review of the literature. The first case was a pure grade 2 NET with pelvic lymph node metastasis (FIGO stage IIIC1). In the second case, a grade 1 NET was associated with high-grade squamous intraepithelial lesion, adenocarcinoma in situ and human papillomavirus (HPV)-associated adenocarcinoma and was FIGO stage IA1. The third patient underwent chemoradiotherapy following a biopsy diagnosis of a high-grade NEC which was radiologically FIGO stage IIIC1 and salvage hysterectomy revealed residual tumor with features of a grade 1 NET. In all cases, the NET was diffusely positive with at least 2 of the neuroendocrine markers chromogranin, synaptophysin, and CD56. The first tumor was p16 negative and the third exhibited block-type immunoreactivity. Molecular tests revealed high risk HPV types 18 and 51 in the third case but no HPV in the first case. p16 immunohistochemistry and HPV molecular testing was not available in the second case. The patients remain disease free with follow-up ranging from 2 to 8 yr. Since a combination of NET and NEC is extremely rare at all sites due to a different pathogenesis, we speculate that in the third case, the NET developed out of the NEC as a “maturation” phenomenon secondary to chemoradiotherapy.

Androgen-induced Hyperplastic Prostatic Glands in the Uterine Cervix

High-grade Endometrial Carcinomas With Solid Basaloid Morphology and Geographic Necrosis Lacking Definitive Pilomatrix-like Features: Clinicopathologic Characteristics Including Aggressive Behavior and Novel Molecular Events

High-grade endometrioid carcinomas occasionally demonstrate solid basaloid morphology with geographic necrosis (SB-GN). This pattern is among the defining features of pilomatrix-like high-grade endometrioid carcinoma (PiMHEC), a recently proposed tumor type which is additionally characterized by the presence of shadow cells, abnormal beta-catenin/CTNNB1 mutations, strong CDX2 expression, and poor outcomes. Clinicopathologic overlap between PiMHEC and other high-grade endometrial cancers with SB-GN has not been established. We screened 300 endometrial carcinomas on tissue microarray for SB-GN histology and performed a detailed whole-section morphologic review, immunohistochemical analysis, and next-generation sequencing on all cases bearing this pattern. Four (1.3%) demonstrated SB-GN. All 3 with clinical follow-up had extremely aggressive behavior despite being MMR-deficient; in contrast, only 27% of other MMR-deficient high-grade carcinomas recurred. One SB-GN case met most of the previously outlined diagnostic criteria for PiMHEC including abnormal beta-catenin/CTNNB1 (p.S37P variant) and strong CDX2 expression; notably, however, shadow cells were absent. This case also demonstrated a KRAS p.A59T pathogenic variant. The other 3 cases also lacked shadow cells; the 2 with sequencing data bore no CTNNB1 abnormalities but showed likely oncogenic variants involving the pilomatrixoma-associated gene FGFR2. All 3 cases with molecular results also bore somatic Notch pathway (NOTCH1/NOTCH2/NOTCH3) variants. The single case treated with immunotherapy showed complete and sustained response with regression of bone metastases despite abnormal beta-catenin/CTNNB1, which has been associated with immunotherapeutic resistance. These data suggest that the SB-GN pattern may connote a poor prognosis even in the absence of overt pilomatrix-like differentiation, and that novel molecular events may have implications for the treatment of these tumors.

Clinicopathologic Evaluation and Molecular Profiling of Recurrent Stage IA Endometrial Endometrioid Carcinoma: A Case-control Study

Most low-grade, early-stage endometrial endometrioid carcinomas (EEC) have an excellent prognosis; however, recurrences occur in a small subset with several studies reporting an increase in CTNNB1 exon 3 mutations in this population. Herein we evaluated 10 recurrent low-grade (FIGO 1 or 2), early-stage (FIGO IA) EECs matched to 10 nonrecurrent EECs to further characterize their clinicopathologic features and molecular phenotype. Cases were matched to controls based on size, grade, and depth of invasion. All tumors were evaluated for specific clinicopathologic parameters followed by next-generation sequencing using a 1213 gene panel. Recurrent EECs demonstrated no significant clinicopathologic differences when compared with nonrecurrent EECs, in terms of age, body mass index, pattern of invasion, presence of endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia, associated metaplastic changes, peritumoral lymphocytes, mitoses, and tumor-infiltrating lymphocytes. Both cohorts also showed a similar number of pathogenic mutations, including CTNNB1 exon 3 mutations, as well as tumor mutational burden and microsatellite profiles. Although in this particular study, the lack of correlation between CTNNB1 exon 3 mutation and recurrence might be secondary to a small sample size, it also suggests the presence of other contributing factors. Thus, it helps set the foundation for larger series incorporating whole genome, transcriptome, proteome, and epigenome analyses to answer this clinically important question.

Napsin-A Expression in Mesonephric and Mesonephric-like Adenocarcinomas: Implications for Distinction From Clear Cell Carcinoma

Mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA) are rare gynecological neoplasms that sometimes exhibit morphologic overlap with clear cell carcinoma (CCC), which may lead to diagnostic challenges. Napsin-A is regarded as the most specific immunohistochemical marker of CCC, but its expression in MLA and MA has not been widely investigated. This study investigated the expression of Napsin-A in a series of MAs and MLAs to determine its utility in distinguishing these neoplasms from CCC. The cohort included 32 MLAs arising in the ovary, endometrium, abdominal wall, and sigmoid mesocolon, 13 cervical MLAs, 2 ovarian mesonephric-like carcinosarcomas, and 1 cervical mesonephric carcinosarcoma, with Napsin-A immunohistochemistry performed on whole-slide tissue sections. Napsin-A staining was positive in 17 of 48 cases (35.4%), with focal granular cytoplasmic expression ranging from 1% to 40%. In all, 13/32 (40.6%) MLAs, 2/13 (15.4%) MAs, and 2/3 (66.7%) mesonephric or mesonephric-like carcinosarcomas were positive. Our results demonstrate that Napsin-A is expressed in a significant subset of MLAs and MAs. Given the morphologic and immunohistochemical overlap, this may contribute to misclassification as CCC, especially in cases with ambiguous morphology. Pathologists should be aware of this diagnostic pitfall and employ a panel of markers rather than relying on a single marker.

The Spectrum of Vascular Lesions of the Upper Female Genital Tract: A Report of 55 Cases

Upper female genital tract vascular proliferations are rare and generally not well characterized. We evaluated types, differences in distribution, and associations of such lesions. Fifty-five vascular lesions were identified: 42 benign (ovary 24; uterine corpus 11; para-adnexal 4; fallopian tube 1; ovaries, fallopian tubes, and corpus 1; ovary and fallopian tube 1) and 13 angiosarcomas. Patients with benign vascular lesions had a mean age of 55 (range: 13–82) yr. Twenty-six lesions were incidental findings, and 11 were associated with clinical manifestations. They had a mean size of 2.0 (range: <1–13) cm, and often were grossly cystic and hemorrhagic. Uterine benign vascular lesions included 6 arteriovenous malformations, 3 venous hemangiomas/malformations, 2 cavernous hemangiomas, and 1 mixed venous-cavernous hemangioma. In the ovary, there were 10 anastomosing hemangiomas, 8 arteriovenous malformations, 6 venous (2 in mature cystic teratomas, 1 bilateral in a patient with Klippel-Trenaunay syndrome), and 2 cavernous hemangiomas. Anastomosing hemangiomas were frequently associated with peripheral stromal luteinization/hilar cell hyperplasia; intravascular growth, extramedullary hematopoiesis, and one with adipocytic metaplasia. Venous hemangiomas/malformations were noted at a younger age in the ovary when compared to the uterine corpus. Patients with angiosarcomas had a mean age of 32 (range: 12–58) yr and a mean tumor size of 9.7 (range: 1.5–23) cm. Eight presented with a pelvic mass. Most angiosarcomas were grossly hemorrhagic and/or necrotic. Eleven arose in the ovary, 4 of them were associated with mature cystic teratoma, 1 with adenosarcoma with sarcomatous overgrowth, and 1 was part of a malignant mesenchymoma. Five were predominantly spindled, 3 epithelioid, 2 spindled and epithelioid, and one pleomorphic. Both uterine angiosarcomas were epithelioid. Follow-up was available for 8 patients: 7 died of disease between 6 and 43 mo, and 1 was alive and well at 106 mo. Vascular lesions in the upper female genital tract are uncommon, morphologically heterogeneous, and more frequent and clinically evident in the adnexa. Anastomosing hemangioma is the most common benign vascular lesion in the ovary and may be misdiagnosed as a steroid cell tumor due to associated stromal luteinization/hilar cell hyperplasia. Arteriovenous malformation is the most common benign vascular lesion in the uterine corpus. Angiosarcomas may be associated with another neoplasm, more commonly mature cystic teratoma, and have a poor prognosis.

PTCH1::GLI1 Fusion Tumors of the Ovary: A Clinicopathologic Study of 3 Cases

GLI1-altered tumors of the gynecologic tract are extremely rare. We report 3 cases of ovarian PTCH1::GLI1 fusion tumor in patients ranging from 54 to 58 yrs of age, who presented with unilateral FIGO stage I tumors. The tumors ranged from 12 to 20 cm and consisted of uniform epithelioid cells with eosinophilic/clear cytoplasm, arranged in nests and trabeculae surrounded by delicate vessels. Variable features included short spindle cells within a myxoid stroma, follicles, small glands/Call-Exner body-like structures, dilated vessels/blood lakes, focal pleomorphism, nuclear grooves, and necrosis. Mitoses ranged from 1 to 10/10 HPFs. Immunohistochemical marker results/number of tumors tested (including primary tumors and recurrences) were as follows: positive for SF-1 (6/6), CD56 (4/4), EMA (3/5), keratins (3/5), SMA (2/5), CD10 (3/4), S100 (3/4), caldesmon (2/3), D2-40 (2/2), Ber-EP4 (2/2), and MOC-31 (1/1), and negative for WT-1 (5/5), calretinin (5/5), inhibin (4/5), ER (4/5), and PR (5/5). Diagnoses initially rendered included adult granulosa cell tumor, unclassified sex cord-stromal tumor, low-grade Müllerian adenocarcinoma, and low-grade endometrioid stromal sarcoma. Surgery was the primary treatment for all. One patient had multiple recurrences at 7, 9, and 13 yrs, had additional surgery, received chemotherapy and radiotherapy, and was alive with no evidence of disease at 13.6 yrs. Another patient had omental recurrence at 5 yrs, received chemotherapy, immunotherapy, and tyrosine kinase inhibitor-targeted therapy, and was alive with disease at 7.9 yrs. The third patient was alive with no evidence of disease at 2 mos. Ovarian PTCH1::GLI1 fusion tumors represent a diagnostic challenge and may recur after several years. Their proper recognition may prompt the use of targeted therapy.

Characterization of High-grade Serous Carcinoma Involving the Ovarian Surface Epithelium-peritoneal Junction

Junctions between different types of epithelia are hotspots for carcinogenesis. The peritoneal mesothelium of the mesovarium transitions to the ovarian surface epithelium at the ovarian hilus (the ovarian surface epithelium-peritoneal junction). There are limited histologic data on this junction in humans. We examined 143 examples of this junctional region in 76 patients with normal ovaries and in 150 patients with extrauterine high-grade serous carcinoma (HGSC). In the absence of significant pathologic processes in the region, this is normally a clearly demarcated, quiescent junction that is usually present directly over the interface of the ovarian stroma with the fibrovascular tissue of the mesovarium. When the ovarian surface epithelium (OSE) and mesothelial linings are well-preserved, the epithelial change at this junction is clearly visible when the OSE is cuboidal or columnar (seen in 79%). When the OSE is flat, no junction is visible (21%). The junction is sharply demarcated in 69%, and in 10% the OSE displays a progressively shorter epithelial height in its transition to the flat mesothelium. Transitional cell metaplasia occurs in the immediate vicinity in 11% of cases. In women with HGSC, tumor was present within 2 mm of this region in 41%. Carcinoma was confined to the ovarian/peritoneal surface in 15% and invaded the stroma without surface involvement in 16%. Carcinoma involved both the surface and invaded the underlying stroma in 11%. In our previous report from this cohort, 40% had serous tubal intraepithelial carcinoma (STIC). In the junctional region, intraepithelial HGSC was seen at the ovarian or peritoneal surface or within ovarian surface epithelial inclusions in 7 cases. Among these 7, fallopian tube tissue was evaluable in 5, and STIC was present in 2 (40%). Our findings characterize the histologic features of the normal ovarian surface epithelium-peritoneal junction and the involvement of this region in extrauterine HGSC.

Endometrial, Ovarian, and Peritoneal Involvement by Endometrioid Carcinoma, Yolk Sac Tumor, and Endometriosis: Molecular Evidence for a Shared Precursor

Recent studies have provided molecular confirmation that a subset of yolk sac tumors is somatically derived. Somatically derived yolk sac tumors are typically diagnosed in older women and are often seen adjacent to epithelial proliferations (such as endometriosis or endometrioid carcinoma) with which they share mutations. Here, we present a case of a postmenopausal woman with a yolk sac tumor and endometriosis in the right ovary, endometriosis with glandular crowding and reactive changes in the left ovary, endometrial endometrioid carcinoma, and yolk sac tumor involving the serosa of the colon. Targeted next-generation sequencing of these five tumor components demonstrated identical mutations in PTEN (p.R130G), PIK3CA (p.G1049S), FGFR2 (p.S252W), and FBXW7 (p.R689Q), suggesting that all components arose from a common precursor. The endometrial endometrioid carcinoma harbored additional exclusive mutations involving PIK3CA (p.H1048R) and CTNNB1 (p.S37F).

Premature Classification of Early-stage Endometrioid Ovarian Carcinoma With Mesonephric-like Differentiation as Mesonephric-like Adenocarcinoma

Ovarian mesonephric-like adenocarcinoma (MLA) is a rare tumor with potential origins in endometriosis and Müllerian-type epithelial tumors. The morphologic patterns of MLA overlap with those of endometrioid ovarian carcinoma (EnOC). We speculated that a subset of MLAs would be classified as EnOCs. In this study, we attempted to identify MLAs from malignant endometrioid tumors. Given that the study patients with MLAs had both endometrioid-like and mesonephric-like morphologies, we defined mesonephric-like differentiation (MLD) as an endometrioid tumor with focal or diffuse MLA morphology and immunophenotype. Twelve patients exhibited mesonephric-like morphologic patterns. Immunohistochemistry analysis for CD10, TTF-1, estrogen receptor (ER), GATA3, calretinin, and PAX8 expression was done using whole-section slides. Two patients without the MLA immunophenotype were excluded. Ten patients with EnOCs with MLD (8.3%) were identified from a cohort of 121 patients with malignant endometrioid tumors. All 10 patients were positive for TTF-1 and/or GATA3. Most patients were ER-negative. Morphologically, MLD was associated with papillary thyroid carcinoma-like nuclei, flattened cells, tubular, nested, reticular, or glomeruloid architecture, and infiltrative growth. All 10 patients had pre-existing endometriosis and/or adenofibromas. Among the EnOCs with MLD, 5 had coexisting components such as EnOC grade 1 [(G1), cases 4, 7, and 9], mucinous borderline tumor (case 1), and dedifferentiated carcinoma (case 10), with distinct borders between EnOC with MLD and the other components. Nine of the 10 MLA patients (90%) harbored KRAS hotspot mutations. In addition, 4 patients harboring other components shared common KRAS hotspot mutations. No significant prognostic differences were observed between patients with and without MLD. Based on our findings, we suggest that EnOC with MLD, especially in the early stages and without high-grade components, should be considered a subtype of EnOC. Overtreatment should be avoided in such patients, particularly in the early stages. In this study, as the characteristics between EnOC with MLD and MLA were not distinguishable, we considered both conditions to be on the same spectrum. EnOCs with MLD exhibit the MLA phenotype during disease progression and are prematurely classified as MLA. Nevertheless, more patients with EnOC who have MLD/MLA are required for a more robust comparison between conventional EnOC according to staging and grading.

Female Adnexal Tumor of Probable Wolffian Origin (FATWO): An Unusual Case With Development of Peritoneal Lesions After 3 Decades

Female adnexal tumor of presumed Wolffian origin (FATWO) is a rare gynecologic neoplasm favored to arise from mesonephric (Wolffian) remnants. Although most tumors are benign, rare recurrences have been reported. Herein, we present a case of a 65-year-old female with incidental peritoneal lesions detected on routine ultrasound that morphologically and immunohistochemically were diagnostic of FATWO. Review of her medical history uncovered a remote history (>30 years) of a para-ovarian cystectomy, which was punctured intraoperatively. Slide review confirmed the diagnosis of FATWO, thereby suggesting iatrogenic dissemination from the original procedure. This report highlights the importance of a thorough review of the medical record when encountering a nonprototypical location for a distinctive tumor. In addition, the slow-growing nature of these lesions, as well as the absence of atypical histologic features, further contributes to the hypothesis that the majority of FATWOs are benign.

Adenomatoid Tumor Mimicking Peritoneal Carcinomatosis: A Case Report

An adenomatoid tumor (AT) is a benign lesion, which is commonly located in the genital tract of both sexes. We present a case of a 66-yr-old woman with the unusual characteristics of an AT mimicking peritoneal carcinomatosis. The tumor was detected incidentally by ultrasound examination, and an ensuing imaging study raised suspicion of ovarian cancer with peritoneal carcinomatosis. From the pathologic diagnosis of frozen specimens, clear cell carcinoma was noted and the patient subsequently underwent cytoreductive surgery. An 8.5-cm-sized mass was observed on the uterine serosa, extending into the myometrium. In addition, multi-cystic nodular lesions were identified in the omentum, appendiceal and small bowel serosa, and the peritoneum. After histologic and extensive immunohistochemical examinations, the final diagnosis was AT. Recognition of the diverse presentations of AT is crucial for accurate diagnosis and appropriate treatment, as these tumors can involve multiple sites and mimic peritoneal carcinomatosis, potentially leading to a misdiagnosis of malignancy.

Tumor Budding, Poorly Differentiated Clusters, and Stroma Percentage in Uterine Endometrioid Carcinomas Are Morphologic Findings Associated With Adverse Clinical Outcomes

Uterine endometrioid carcinoma (UEC) has well-defined morphologic features that carry prognostic significance and guide treatment. In addition to the well-known features, tumor budding (TB), poorly differentiated clusters (PDCs), and amount of stroma within the invasive front are associated with a poor prognostic outcome in many carcinomas. Here, we evaluate TB, PDCs, and the stroma percentage in UEC and correlate these findings with morphologic features known to be associated with a poor clinical outcome and with recurrence-free survival (RFS). We performed a retrospective search of our institution’s EMR for cases of hysterectomy for UEC. We collected clinical data including disease recurrence, death, and data associated with poor patient outcomes. Cases were evaluated for TB, PDCs, and percent stroma by 2 pathologists. Ten 20× fields were examined, and the one with the most PDCs and TB was evaluated. Percent stroma was evaluated in a ×10 field of tumor at the area of deepest invasion. Less than 10% stroma was defined as stroma poor, and >10% stroma was defined as stroma rich. Statistical testing and analysis were conducted, and P-value was set at 0.05. One hundred thirteen cases were evaluated. Decreased RFS was seen with TB (P=0.03), at least 5 PDCs (P=0.01), and stroma-rich tumors (P=0.043). This study shows a statistically significant association between TB presence, at least 5 PDCs, stroma-rich tumors, and decreased RFS in UEC. We conclude that TB, PDCs and stromal evaluation are strong independent prognostic indicators in UEC and provide additional value to the currently used morphologic assessment of UEC.

Novel Androgen Receptor Splice Variant 7 in Gynecologic Tumors

Androgen receptor splicing variant 7 (AR-V7) is a truncated variant of the AR mRNA that may be a predictive biomarker for AR-targeted therapy. AR-V7 has been described in prostate, breast, salivary duct, and hepatocellular carcinomas as well as mammary and extra-mammary Paget disease. We report 2 gynecologic cancers occurring in the lower uterine segment and ovary and both harboring AR-V7 by targeted RNA sequencing. The uterine tumor was an undifferentiated carcinoma consisting of epithelioid cells and focally spindled cells arranged in sheets, nests, and cords associated with brisk mitotic activity and tumor necrosis. The ovarian tumor consisted of glands with cribriform and solid architecture and uniform cytologic atypia. ER and PR were positive in the ovarian tumor and negative in the uterine tumor. Both were positive for AR and negative for HER2, GATA3, and NKX3.1. DNA methylation profiling showed epigenetic similarity of the AR-V7-positive gynecologic cancers to AR-V7-positive breast cancers rather than to prostate cancers. AR-V7 may underpin rare gynecologic carcinomas with undifferentiated histology or cribriform growth reminiscent of prostatic adenocarcinoma and breast invasive ductal carcinoma.

Stromal p16 and SATB2 Expression Does Not Distinguish Atypical Polypoid Adenomyoma (APA) From its Benign Mimics

Atypical polypoid adenomyoma (APA) is a polypoid biphasic lesion of low malignant potential that arises in the lower uterine segment and uterine corpus. The diagnosis of APA is often challenging on biopsy and curettage specimens, and both benign and malignant processes need to be considered in the differential. Stromal expression of p16 and SATB2 have recently been shown to distinguish APA from myoinvasive endometrioid carcinoma. The authors hypothesized that p16 and SATB2 immunohistochemistry could also aid in the distinction of APA from benign adenomyomatous polyp and endometrioid adenomyoma. The study comprised 10 APAs, 7 adenomyomatous polyps, 11 endometrioid adenomyomas, and 10 myoinvasive endometrioid carcinomas. The majority of APAs showed moderate to strong, diffuse p16 and stromal expression. However, most adenomyomatous polyps and endometrioid adenomyomas also exhibited moderate to strong, focal to diffuse p16 stromal expression. SATB2 showed weak to moderate, focal to diffuse expression in the majority of APAs, adenomyomatous polyps and endometrioid adenomyomas. In contrast, p16 and SATB2 were negative to weak and focal in 90% of myoinvasive endometrioid carcinomas. Our findings demonstrate that p16 and SATB2 may be helpful in the differential diagnosis of myoinvasive endometrioid carcinoma and APA while not useful in separating APA from adenomyomatous polyp and endometrioid adenomyoma.

Dedifferentiation in Breast Metastasis of Endometrial Carcinoma: A Diagnostic Dilemma

Most breast tumors are primary to this site; breast metastasis of endometrial origin is extremely rare. Low-grade endometrioid endometrial carcinomas can undergo dedifferentiation to undifferentiated carcinoma but such transformation at a metastatic site has been reported previously in only 2 cases. We report a case of dedifferentiation occurring in an isolated solitary breast metastasis of a low-grade endometrioid endometrial carcinoma. A 64-yr-old woman presented with a breast mass 2 yr after initial diagnosis of a grade 1 FIGO stage IIIA endometrioid endometrial carcinoma. Ultrasound guided biopsy of the breast mass showed a grade 1 endometrioid carcinoma which was diffusely estrogen receptor and PAX8-positive, consistent with metastasis from the previous endometrial carcinoma. The tumor initially responded to Letrozole therapy but then abruptly increased in size. Mastectomy revealed a poorly differentiated malignant tumor with morphology and immunophenotype (including loss of ARID1A and ARID1B immunoreactivity) consistent with undifferentiated endometrial carcinoma with no residual low-grade component. Awareness of the phenomenon of dedifferentiation of endometrial carcinoma in a metastatic site is important to avoid misdiagnosis as a primary breast cancer or metastasis from another primary site.

Implementation of Frozen Section Services for Gynecologic Surgeries in a Single Institution in Ethiopia: Results of a Pilot 12-Month Experience and Implications for Introduction into Low- and Middle-Income Countries

Intraoperative frozen section provides surgeons with information that guides them to perform the most reasonable procedure. The aim of the study was to determine the accuracy of FS and share the experience of establishing FS services for implementation in similar low- and middle-income countries. This pilot study was conducted between January 2022 and December 2022, including women who underwent gynecologic surgeries, using a structured questionnaire. Data was analyzed with SPSS 23.1, and tables were employed for data presentation. The overall accuracy, sensitivity, and specificity of frozen section analysis were calculated, and the experiences of establishing frozen section services are shared. Seventy-six frozen section samples were sent for histopathology analysis. Seventy (92%) cases comprised adnexal lesions, 3 (4%) cases represented uterine lesions, and 3 (4%) cases were lymph nodes. Most (70%) of the ovarian samples were reported as benign, and 18 (26%) as malignant. One of the 3 uterine samples was reported as sarcoma, and 2 of the lymph nodes as secondary malignancy. The overall accuracy of frozen section for the detection of any benign, borderline, and malignant ovarian neoplasms was 90%. The average turnaround time was 25 min and was more than 30 min in 39% of cases. Although FS pathology helped avoid unnecessary extensive surgeries in some patients, it was inappropriately utilized in 30% of the cases, and mechanisms to address discrepant results and assuring quality were not robust. The overall accuracy of the frozen section was comparable to most international data, demonstrating its feasibility and practicality in low-resource settings. However, quality improvement mechanisms should be thoroughly considered.

Ovarian Teratomas Unveiled: Pathologists’ Curiosity Reveals Intriguing Associations in the Enigmatic Realm

Mature and immature teratomas can coexist with other tumor types and they may undergo malignant change in any one of their elements. In the present study, we present our institutional experience of these rare associations with teratomas. This was a retrospective study over a period of 10 years (January 2014 to December 2023) on histopathologically diagnosed cases of ovarian teratomas. The clinicopathologic features of malignant transformation (MT), other associations, as well as co-existing tumors with ovarian teratomas were analyzed. There was a total of 602 (21%) ovarian teratomas out of all ovarian tumors (n=2858) reported during the study period. In all, 41/602(6.8%) cases were immature teratomas with the presence of gliomatosis peritonei in 7 cases. Mature cystic teratoma (MCT) cases also had gliomatosis peritonei (n=9) along with nodal gliomatosis in 3 cases. Neoplasms arising in teratomas (n=6) included carcinoid tumor (n=2), small cell neuroendocrine carcinoma (n=1), mucinous adenocarcinoma (n=2), and low-grade mucinous neoplasm of the appendix present within the teratoma (n=1). Of a total of 18 cases of struma ovarii, one case each of papillary thyroid carcinoma and follicular thyroid carcinoma was seen. Squamous cell carcinoma (n=4) was the commonest malignant transformation noted. Growing teratoma syndrome (n=4) and NMDA-associated encephalitis (n=3) associated with teratoma were also seen. Neoplasms/conditions co-existing with teratomas in the same ovary (n=9) included mucinous cystadenoma (n=1), serous cystadenofibroma (n=1), high-grade serous carcinoma (n=1), fibrothecoma (n=2), hydatid cyst (n=1), sclerosing stromal tumor (n=1), adult granulosa cell tumor (n=1), and metastatic signet ring cell carcinoma (n=1). Although the clinical course of MCT is typically indolent, pathologists should be aware of malignant transformation and other rare co-existing entities, highlighting the importance of adequate sampling of the tumors.

Mesonephric and Mesonephric-like Adenocarcinomas of the Gynecologic Tract: A Case Series and a Review of the Literature

We sought to present and describe all cases of mesonephric adenocarcinoma (MNAC) and mesonephric-like adenocarcinomas (MLAs) at our institution. These cancers are rare, morphologically similar tumors of the female reproductive tract. In this case series, we present 13 new cases of MNAC/MLA that were identified at St. Luke’s University Health Network from 2016 to 2024. Demographics, clinical characteristics, and pathologic findings were collected from chart review. There were 6 uterine, 5 ovarian, and 2 cervical MNAC/MLAs. At presentation, more than half of the patients presented at early stages with 7, 2, 3, and 1 diagnosed at stages I, II, III, and IV, respectively. All patients underwent upfront surgical resection and were recommended adjuvant therapy. One patient declined adjuvant treatment. At the time of writing, 9 of 13 patients have completed treatment and have no evidence of disease, 1 is alive with disease, 1 is currently undergoing treatment, and 2 died of disease. Median overall survival (OS) was 15 mo (95% CI: 2.2–27.8 mo). Current literature regarding MNACs/MLAs suggests an overall poor prognosis, with the majority presenting at advanced stages. This case series describes patients diagnosed with early-stage disease and reports on their histopathology, treatment regimens, and clinical outcomes. The majority of these patients are without recurrence after upfront treatment. Continued surveillance of these patients to determine long-term outcomes is necessary to further elucidate overall prognosis.

Ovarian Mesonephric-like Adenocarcinoma Recurring With a Rhabdomyosarcoma Component: A Case Report

Mesonephric-like adenocarcinoma (MLA) has recently been described as a tumor of the endometrium or ovaries, which, morphologically and immunohistochemically, resembles mesonephric adenocarcinoma arising mostly in the uterine cervix. Herein, we report, to our knowledge, the first case of ovarian MLA that developed into an extremely rapidly growing recurrent mesonephric-like carcinosarcoma, as confirmed by a genomic profiling test. A 51-year-old woman underwent chemotherapy with complete debulking surgery for ovarian carcinoma. Pathologically, the patient was diagnosed with stage IVB ovarian MLA. Subsequent to 15 months of complete remission, an enhanced computed tomography scan revealed a solid tumor of 10 cm diameter in the abdominal cavity. Secondary surgery was terminated with a 2 cm2 tumor biopsy specimen collection considering perioperative complications. Histologically, the tumor consisted of short spindle cells, and immunohistochemical staining revealed a rhabdomyosarcomatous profile without an epithelial component. Despite treatment for the sarcoma, she died 3 months after the detection of the tumor. The genomic profiling of the primary ovarian carcinoma and secondary resected tumor biopsy specimens revealed an identical KRAS mutation in both. Therefore, we concluded that the ovarian MLA recurred with a rhabdomyosarcoma component.

Uterine Neurotrophic Tyrosine Receptor Kinase Rearranged Spindle Cell Neoplasms: Three Cases of an Emerging Entity

Uterine sarcomas are rare; most are either smooth muscle or endometrial stromal in origin. Recent molecular advances have identified several, genetically defined entities with specific morphologic, clinicopathological associations, and therapeutic options. We report 3 cases of uterine neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasms,” currently classified as “emerging entities” in the WHO Classification of Female Genital Tract Tumors, 2020, Fifth Edition. The affected patients were 32, 34, and 42 years of age. Two patients presented with vaginal bleeding; the third presented with a cervical mass found incidentally during laparoscopy for an ectopic gestation. All 3 tumors were polypoid masses that distorted the cervix. Microscopically, they comprised cellular, fascicular, and storiform, plump spindle cells, with occasional rounded cells, and frequent mitoses (4–48/10 high power fields) in a myxoid stroma. All 3 cases showed entrapment of benign cervical glands. Inflammatory cell infiltrates, including plasma cells, were noted in all 3 tumors. One case had tumor cell necrosis, osteoid-like material, and osteoclast-like giant cells and showed lymphovascular invasion. Immunohistochemically, our cases showed patchy S100 (2/3) and CD34 (3/3) positivity. CD10 was positive in 2/3 cases. 3/3 cases showed pan-tropomyosin receptor kinase positivity (cytoplasmic). The NTRK-translocations demonstrated were: NTRK1::TMP3, NTRK1::TPR, and NTRK3::SPECC1L. Two of the patients had extensive disease and underwent chemotherapy. Larotrectinib was approved for one patient who demonstrated a striking reduction in tumor volume upon initiation of this treatment.

Dedifferentiated Leiomyosarcoma-morphology, Immunohistochemistry, and Molecular Findings of a Case and Review of Literature

We present a case of uterine dedifferentiated leiomyosarcoma in a 42-yr-old woman who presented with severe abdominal pain and vaginal bleeding. The mass measured 10.5 cm. The “differentiated” tumor component ranged from leiomyoma-like areas to smooth muscle tumor of uncertain malignant potential to frank leiomyosarcoma. The undifferentiated tumor component showed extreme hypercellularity, intermediate to large polygonal cells, with significant cytologic atypia and numerous mitotic figures (67 mitotic figures per 10 high-power fields). This undifferentiated component imperceptibly blended into more recognizable smooth muscle areas. In contrast to the differentiated component, the undifferentiated component lacked staining for smooth muscle markers. Targeted next-generation sequencing revealed TP53, NF1, and NOTCH2 mutations in both differentiated and undifferentiated components. In addition, the undifferentiated tumor component also harbored multiple additional chromosomal abnormalities including gains in 1q, 22q, and copy number losses in 3p, 9p, and 11q. The undifferentiated tumor component was also identified in an adhesion involving the small bowel and omentum at complete staging. The patient was subsequently treated with 6 cycles of adriamycin chemotherapy. Computerized tomography scan after 3 cycles showed no residual disease. Published literature regarding dedifferentiated leiomyosarcoma is reviewed.

Metastatic Leiomyoma With Malignant Transformation Harboring RAB2A-PLAG1 Fusion: A Case Report and Review With Molecular Analysis

Metastasizing leiomyoma is a rare condition characterized by the development of benign-appearing smooth muscle neoplasms at extrauterine sites in patients with a history of uterine leiomyoma. These lesions occur most commonly in the lung, with the abdominopelvic and mediastinal lymph nodes being other reported sites. Malignant transformation of metastasizing leiomyoma is extremely rare, with only a few cases described in the literature. We describe a case of metastasizing leiomyoma with malignant transformation in a middle-aged Asian lady, who developed pulmonary metastatic foci 12 years after surgical excision of the original uterine leiomyomata. Molecular analysis showed a common RAB2A-PLAG1 fusion gene and identical single nucleotide variants in both tumor foci, with significantly more pronounced segmental chromosomal copy number variations in one focus showing high-grade features. A comprehensive review of the literature lends support to the hypothesis that the original leiomyomata and the metastatic foci are clonally related, with high-grade features being associated with more complex genomic signatures.

Precursor Lesions of Cervical Clear Cell Carcinoma: Evidence For Origin From Tubo-Endometrial Metaplasia

Cervical clear cell carcinoma (CCC) is an HPV-independent tumor historically associated with in-utero exposure to diethylstilboestrol. With the cessation of diethylstilboestro use, most contemporary cases are sporadic and of uncertain pathogenesis, with no established precursor lesion. Following the detection of 3 incidental “early” (FIGO stage IA1) cervical CCCs, all of which displayed adjacent tubo-endometrial metaplasia, we examined further cases, including resection specimens, of this tumor in an attempt to delineate potential precursors. We identified tubo-endometrial metaplasia in proximity to the tumor in 5 of 5 additional primary cervical CCCs, with some tubo-endometrial glands exhibiting subtle mild cytologic atypia. This observation adds to the sparse existing literature proposing tubo-endometrial metaplasia as a precursor to sporadic cervical CCC, with possible progression via an “atypical” transitional phase to malignancy. We also review the published literature regarding possible precursor lesions of primary cervical CCC.

Evaluation of SWI/SNF Protein Expression by Immunohistochemistry in Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinomas (OCCC) are known to harbor ARID1A mutations, and several recent studies have described immunohistochemical loss of SMARCA2, SMARCA4, and SMARCB1 in a subset of tumors. We performed ARID1A, SMARCA2, SMARCA4, and SMARCB1 immunohistochemistry on 105 OCCCs to identify possible associations with clinicopathologic features and assess their prognostic value in these tumors. ARID1A, SMARCA4, and SMARCB1 were considered retained if any tumor cell nucleus stained while for SMARCA2, >5% of tumor nuclei were required to be positive. Patients had a mean age of 56 yr and tumors averaged 13 cm in size. Most patients (63%) had stage I tumors with 47% being alive and well, 41% dead from disease, 10% dead from other causes, and 3% alive with disease at last follow-up (mean 72 mo). Tumors showed an admixture of architectural patterns, but papillary was most frequent (49%). Stromal hyalinization was detected in 83% of OCCCs and a background precursor in 78%. High-grade atypia and/or oxyphilic cells were noted in 45% and 29% of tumors, respectively. All OCCCs expressed SMARCA4 and SMARCB1, but the absence of ARID1A was noted in 30% of tumors and SMARCA2 in 8%. ARID1A-retained OCCCs were associated with a dominant tubulocystic or solid pattern, but no other clinicopathologic features reached statistical significance. No switch/sucrose non-fermentable protein expression was predictive of prognosis. Additional studies with known mutational status of these proteins are warranted to better assess their prognostic utility and develop a standardized immunohistochemical scoring system.

Ovarian Microcystic Stromal Tumor With Intraovarian Recurrence and Peritoneal and Omental Spread: A Case Report With Morphological, Immunohistochemical, and Molecular Analysis

Microcystic stromal tumors (MCSTs) are rare ovarian stromal tumors. They harbor CTNNB1 or APC mutations, resulting in β-catenin nuclear expression. To date, all MCST cases treated with oophorectomy or more extensive surgery have followed benign clinical courses. However, 1 of the 3 cases treated with ovarian cystectomy/tumor resection recurred in the residual ovary and iliac fossa 9 years after ovarian cystectomy. Here, we report a case of recurrent MCST in a 38-year-old woman. The patient underwent ovarian cystectomy for a 7.5 cm solid-cystic right ovarian mass, which showed classic morphological and immunophenotypical features of MCST. Four years later, the tumor recurred in the residual right ovary as a 21 cm mass, involving the pelvic peritoneum and omentum. Molecular analysis using next-generation sequencing revealed a single CTNNB1 exon 3 S37A mutation in the recurrent tumor. To the best of our knowledge, this is the second case of recurrent MCST, which presents more evidence that MCST has the potential to recur and spread locally. Rather than ovarian cystectomy/tumor resection, more aggressive surgery, such as unilateral oophorectomy, may be necessary to decrease the risk of recurrence. Long-term postsurgery follow up is needed, especially after simple ovarian cystectomy/tumor resection.

Update on the ISGyP Endocervical Adenocarcinoma Project

TRPS1 Reliably Stains Benign and Malignant Lesions Arising Within Vulvar Anogenital Mammary-like Glands

TRPS1 is a novel immunohistochemical marker that is known to stain normal mammary epithelium and breast carcinomas (especially triple negative carcinomas). TRPS1 staining has also been reported in normal skin appendages, benign and malignant cutaneous neoplasms, and anogenital mammary-like glands (AGMLG). However, research regarding TRPS1 staining in various neoplasms derived from AGMLG is limited. Past studies have focused on two neoplasms of AGMLG—hidradenoma papilliferum (HP) and extramammary Paget disease (EMPD). We confirm the finding that TRPS1 is positive in the epithelium of HP and we report its expression in a variety of other benign and malignant lesions derived from vulvar AGMLG, including fibroepithelial lesion (FEL), lactating adenoma (LA), fibroepithelial polyp with AGMLG, and mammary-type adenocarcinoma (MAc). The majority of TRPS1 staining was diffuse and displayed strong (3+) intensity. We show that TRPS1 is significantly more sensitive than GCDFP-15 in lesions of AGMLG and is comparable to GATA3. TRPS1 was also more sensitive than mammaglobin, but the finding did not reach statistical significance. TRPS1 demonstrated diffuse staining in these lesions significantly more often than either GCDFP-15 or mammaglobin. This study was limited by its small sample size, due to the rarity of some entities such as the malignant MAc (n=3).

Cellular Angiofibroma With Sarcomatous Transformation: Case Report With Molecular Characterization and Review of the Literature

Cellular angiofibroma is a benign mesenchymal neoplasm which usually occurs in the vulvovaginal or inguinoscrotal areas. Although benign, cellular angiofibroma may rarely undergo sarcomatous transformation. We report a case of vulvar cellular angiofibroma with sarcomatous transformation in a 62-yr-old woman and a literature review of previously reported cases. By immunohistochemistry, our case was positive for vimentin and ER, mostly negative for smooth muscle markers, and showed patchy reactivity for CD10, Pan-TRK, and Rb1. The bland component was negative for p16 with wild-type p53 expression, while the sarcomatous area showed strong, diffuse p16 staining with p53 overexpression. Targeted DNA and RNA next-generation sequencing of the bland area showed chromosome 9p/9q copy number loss, while the sarcomatous area showed TP53 (p.G154V) mutation (90% allele frequency) and copy number loss of chromosome 17p (including TP53 ). Whole transcriptome sequencing was negative for tumor-associated gene fusions. As the lesion was completely encapsulated and excised, and with limited published data indicating an uneventful clinical course, the decision was made to follow the patient with no further therapeutic intervention. Four months following excision, the patient has no signs or symptoms of local recurrence.

Proficiency Testing of p53 Immunohistochemistry Pattern Read-out in Vulvar Biopsies Demonstrates Frequent Basal Overexpression Interpretation in TP53 Wild-type Cases

Recently, criteria for p53 immunohistochemistry (IHC) interpretation were described in squamous neoplasia of the vulva. This pattern-based approach detailed 2 wild-type patterns (scattered and basal-sparing) and 4 mutant patterns (parabasal/diffuse overexpression, basal overexpression, null, and cytoplasmic). However, the proficiency of pathologist read-out has not been studied. We created an online tool to evaluate p53 IHC interpretation proficiency. p53 IHC on 90 vulvar biopsies (n=31 squamous in situ/premalignant and n=59 benign lesions) were scanned (without corresponding H&E). Fifteen pathologists assessed 45 cases in Module A and assigned each case as wild-type or mutant via the 6 p53 IHC patterns. Following Module A, participants were given the suggested p53 IHC pattern and TP53 sequencing data for each case. After self-review, pathologists completed a second 45 case set (Module B). The average pathologist score per case increased from Module A to Module B (69.8%–87.7%, P=0.0005). Pathologist proficiency was excellent in the parabasal/diffuse (100%–100%), null (93.3%–90.0%), and basal-sparing (88.9%–100%) patterns. The greatest discrepancy was due to the interpretation of the basal overexpression pattern in cases that were TP53 wild-type by sequencing, but this improved with educational intervention. Scores for the scattered pattern improved from 64.9% to 82.8% and basal overexpression from 73.3% to 91.1% after completion of the training module. Pathologists should exhibit caution when interpreting p53 IHC as basal overexpression, as this pattern can be seen in the absence of TP53 alterations. There were 2 cases with convincing p53 IHC abnormal patterns (1 parabasal/diffuse and 1 null) without TP53 mutations by sequencing.

Verruciform Acanthotic Vulvar Intraepithelial Neoplasia Harbors Recurrent Genomic Alterations Found in HPV-independent Squamous Cell Carcinoma

The term verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN) was coined to describe HPV-independent p53-wildtype lesions with characteristic clinicopathologic characteristics and association with vulvar squamous cell carcinoma (vSCC). We aimed to expand on the molecular landscape of vaVIN using comprehensive sequencing and copy number variation profiling. vaVIN diagnosis in institutional cases was confirmed by a second review, plus negative p16 and wildtype p53 by immunohistochemistry. Multigene next-generation sequencing and shallow-whole genome sequencing were used to survey for single-nucleotide variants (SNV), copy number alterations, and structural variants. Targeted TERT promoter sequencing was also carried out. Nineteen patients with vaVIN were included; 4 had concurrent vSCC. The median patient age was 74 (range 56–90) years. Genomic aberrations were noted in 18 cases (95%) as follows: PIK3CA in 10 (53%), CDKN2A in 7 (37%), HRAS in 6 (32%), FAT1 and NOTCH1-2 in 5 each (26%), TSC2 in 2 (11%), and PTEN, ARID2, and KRAS in 1 (5%) each. TERT promoter variants were detected in 11 of 13 cases successfully tested (85%). Five vaVINs harbored a TP53 variant but showed wild-type p53 immunohistochemical expression. In one of these, the concurrent carcinoma showed abnormal p53 and biallelic TP53 mutations. Out of 15 patients with follow-up (mean: 20, range: 2–50 mo), vaVIN persistence/recurrence was seen in 8 (53%), and subsequent vSCC in 2 (13%). At the last encounter, 3 (20%) patients had persistent disease and 1 (7%) died of vSCC. vaVIN is characterized by a wider molecular spectrum, beyond known alterations in PIK3CA, HRAS, and ARID2, to include TERT promoter, CDKN2A, FAT1, and NOTCH1-2, which are characteristic of HPV-independent vSCC. vaVIN can occur with concurrent or subsequent carcinoma, sometimes with fatal outcomes. These findings support the concept of vaVIN as a neoplastic process within the family of HPV-independent vulvar neoplasia.

Vulvar Cellular Angiofibroma With Cytologic Atypia and Sarcomatous Transformation: A Clinicopathologic Analysis

Cellular angiofibromas (CAFs) are benign mesenchymal neoplasms of the vulva and lower genitourinary tract. Although most cases are benign with excellent prognosis, data on CAFs with cytologic atypia (aCAF) and sarcomatous transformation (tCAF) is limited. We identified 13 vulvar CAFs comprising 4 aCAFs and 9 tCAFs. The median age at presentation was 49  yr (40–84). All tumors involved the subcutis with a median size of 4.75 cm (0.8–11.7). Vascular and stromal hyalinization was present in all cases. Fascicular growth pattern and chronic perivascular inflammation were seen in 10 cases, followed by wispy collagen in 11 and stromal inflammation in 12. Common features were fat entrapment (n=8), stromal edema (n=7), and hemangiopericytoma-like vessels (n=5), while myxoid change, necrosis (n=3 each), hemorrhage, collagen bundles (n=2 each), solitary fibrous tumor-like appearance, and large hyalinized vessels (n=1 each) were rare. The atypia ranged from isolated atypical cells to foci of multinucleated cells, with brisk mitoses in 1 case. The sarcomatous transformation involved 10% to 80% of total tumor volume and comprised features of well-differentiated liposarcoma, pleomorphic liposarcoma, leiomyosarcoma, and spindle and epithelioid cell sarcoma. Diffuse p16 expression was present in 2 tCAFs. Of 10 patients with available follow-up (median: 103.3 mo, 13.3–156.6), 2 (20%) recurred at 41 mo and 66 mo and remained disease-free at 157 and 99  mo post reexcision, respectively. The study provides a detailed clinicopathologic characterization of rare variants of CAF, aCAFs, and tCAFs, and reports rare recurrences, most likely due to incomplete surgical excision.

Gynecologic Leiomyosarcoma With Epithelioid Features and PGR::NR4A3 Gene Fusion: First Report in the Vulva

Vulval leiomyosarcomas with variant features are rare with limited data available in the literature compared to their uterine counterparts. Gynecologic leiomyosarcoma with nuclear receptor 4A3 (NR4A3) gene fusion is a rare, recently described neoplasm that has been reported mostly in the uterus and rarely in the pelvis. Herein, we report the first case of this entity occurring as a primary vulva tumor in a 46-year-old patient. Histologic examination showed a multi-nodular tumor composed of monomorphic epithelioid, rhabdoid and spindled cells arranged in sheets, cords and microcysts within a richly vascularised, myxoid stroma. On immunohistochemistry, the tumor cells were positive for desmin, smooth muscle actin, h-caldesmon, as well as ER and WT1. Gene fusion analysis revealed the presence of a PGR::NR4A3 gene fusion involving exon 2 of PGR and exon 2 of NR4A3. Local recurrence occurred one year after initial excision. Recognition of this rare subtype of gynecologic leiomyosarcoma in the vulva may help refine the classification of unusual vulvovaginal smooth muscle neoplasms.

TP53 Mutations and PD-L1 Amplification in Vulvar Adenocarcinoma of the Intestinal Type: Insights From Whole Exome Sequencing of 2 Cases

Vulvar adenocarcinoma of the intestinal type (VAIt) is a rare subtype of primary vulvar carcinoma, with ∼30 cases documented in the English literature. This study presents 2 new cases of HPV-independent VAIt with lymph node metastasis and discusses their clinical presentation, histopathologic features, and whole exome sequencing (WES) analysis. Both cases exhibited histologic features consistent with VAIt, including tubular, papillary, and mucinous carcinoma components. Immunohistochemical analysis showed p16 patchy staining, CDX2, CK20, and SATB2 positivity, while being negative for ER, PAX8, and CK7. WES revealed pathogenic TP53 mutations in both cases, accompanied by distinct additional mutations (GRIN2A and KDM6A in Case #1; CHD4 in Case #2). Common copy number alterations (CNAs) included TP53 loss of heterozygosity and CD274/PD-L1 amplification. However, other CNAs varied between the cases. Immunohistochemistry for p53 suggests the presence of both wild-type and mutant subclones, indicating that TP53 abnormalities may be acquired during tumor progression. Both tumors showed mutational signatures SBS1 and SBS5, associated with aging and DNA damage. Our findings deepen the understanding of the genetic events involved in the tumorigenesis of HPV-independent VAIt. Given the TP53 abnormalities and CD274/PD-L1 amplification, emerging p53-based therapies and immune checkpoint inhibitors may represent potential treatment targets. While these findings contribute to the understanding of VAIt tumorigenesis, further research is required to validate these observations in a larger cohort.

A Case of Synchronous Malignant and Benign Granular Cell Tumor of the Vulva

Granular cell tumors (GCT) are rare soft tissue neoplasms, which seldom occur in the vulva. They are more commonly benign, but malignant GCT do occur. We report a case of a 50-yr-old postmenopausal woman who presented with a vulvar lesion that was diagnosed as GCT on biopsy. Imaging and clinical examination revealed an enlarged, likely positive lymph node. Pathology of the subsequently resected total deep vulvectomy specimen showed 2 histologically distinct GCTs. The larger lesion met criteria for malignancy and histologically corresponded to metastatic deposits seen in the pelvic lymph nodes. The separate smaller lesion was histologically benign. This case illustrates a malignant GCT with a synchronous, likely benign GCT both occurring in the vulva. Our case demonstrates the application of histologic criteria in the diagnosis of malignant and benign GCT with discussion on the diagnosis and treatment of this rare tumor.

EML4::NTRK3 Rearranged Ovarian Neoplasm: Case Report and Literature Review

This case report details the first known instance of an EML4::NTRK3 rearranged neoplasm in the ovary. The patient, a 32-yr-old woman, presented with prolonged abnormal uterine bleeding and was found to have a 5.0 cm right adnexal mass. Following surgical excision, histologic examination revealed neoplastic epithelioid to spindled cells with moderate cytologic atypia in a variably myxoid background, while immunohistochemistry confirmed positivity for inhibin, calretinin, and smooth muscle actin (SMA). Molecular analysis identified an EML4::NTRK3 fusion, establishing the diagnosis. This rare finding broadens the spectrum of NTRK fusion-related gynecologic tumors, typically observed in the uterus. Through this report and a literature review, we aim to enhance diagnostic recognition and underscore potential therapeutic strategies for NTRK fusion-positive ovarian tumors.

Heterogeneity and Scoring Reproducibility of Folate Receptor 1 Immunohistochemistry in High-grade Serous Carcinoma

Mirvetuximab soravtansine (MIRV) is an antibody-drug conjugate approved for the treatment of adult patients with folate receptor 1 (FRα; FOLR1) positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received one to three prior systemic treatment regimens. Per the FDA approval, FOLR1 positivity is defined as ≥75% of viable tumor cells showing moderate (2+) or strong (3+) membranous immunostaining (“PS2+”). Given this disease’s high recurrence rate and relatively limited therapeutic options, there is utility in exploring consistency in FOLR1 reporting. Tubo-ovarian high-grade serous carcinoma (HGSC) samples from our institution’s archives were included in tissue microarrays (n=806), whole tissue sections (n=51), or cell blocks (n=30) and evaluated using the Ventana FOLR1 (FOLR1-2.1) RxDx Assay. FOLR1 staining was heterogeneous across different anatomic sites (average FOLR1 PS2+ was 50.2 from adnexal sites compared with 47.4 from omental sites, P =0.015). Similarly, heterogeneity was noted in pre- versus post- neoadjuvant chemotherapy specimens (on average, FOLR1 PS2+ score increased by 17.7 from pre- to post- therapy, P =0.0089). Lastly, specimen type may also influence FOLR1 staining (average abdominal fluid FOLR1 PS2+ score was 25.5 and average surgical FOLR1 PS2+ score was 56.9, P =0.000034). Agreement among 9 readers was initially substantial, with a Fleiss kappa of 0.661 (95% CI: 0.636–0.685). For the subset of cases with the worst agreement initially, a training session with reference cases improved interobserver agreement. Our study highlights several factors contributing to heterogeneity in FOLR1 reporting. Future studies are needed to better understand the impact of FOLR1 heterogeneity on patient response to therapy.

Sex Cord–like Endometrioid Carcinoma Arising From Broad Ligament, a Challenging Diagnosis: Report of 2 Cases

Endometrioid carcinoma is a common malignant epithelial tumor of the uterus and ovary, exhibiting variable histomorphology and immunophenotype. Sex cord–like endometrioid carcinoma (SCLEC) is a rare histologic subtype with significant morphologic and immunohistochemical variability. Extra-ovarian, extra-uterine SCLEC arising from the broad ligament has been rarely reported. We report 2 cases of SCLEC arising from the broad ligament. The first patient, a 62-yr-old woman, presented with vague abdominal pain, and diagnostic imaging suggested a broad ligament fibroid. The second patient, a 47-yr-old woman, presented with a clinical history of abdominal pain and abnormal uterine bleeding. Diagnostic imaging suggested a subserosal fibroid. Histologic evaluation revealed a sex cord–like pattern with only rare foci of conventional endometrioid carcinoma. Immunohistochemical evaluation of both cases showed positivity for CK-7, EMA, ER, PR, CDX-2, CD-10, and nuclear β-catenin, while CK-20, PAX-8, GATA3, TTF-1, WT-1, napsin-A, p16, p53, inhibin, calretinin, chromogranin, and CEA were negative. The diagnosis of primary broad ligament SCLEC is extremely challenging. A thorough histologic and immunohistochemical evaluation is essential before excluding differential diagnoses.

Mesonephric-like Adenocarcinoma (MLA) Diagnostic Criteria and Controversies: Perspectives and Guidance From Pathologists in the MLA Consortium

Mesonephric-like adenocarcinoma (MLA) is a rare and aggressive gynecologic malignancy that has only been recognized in the last decade. It arises in the endometrium, ovaries, and other extrauterine sites (often in association with endometriosis) and closely mimics a variety of other tumor types that occur in these locations. While it shows significant morphologic, immunohistochemical, and molecular homology with cervical mesonephric adenocarcinoma, there are many clinicopathologic features that suggest müllerian derivation, and this is now well established. As research on MLA has accumulated, questions have emerged about optimal practices for the diagnosis of these challenging tumors. In 2022, faculty at M.D. Anderson Cancer Center convened the Mesonephric-like Adenocarcinoma (MLA) Consortium, comprised of international pathologists, gynecologic oncologists, medical oncologists, radiation oncologists, and basic science investigators with expertise in MLA, with the goals to enhance understanding of these tumors, refine diagnostic criteria, improve treatment options, and facilitate research collaborations. An initial review from the consortium was published in 2025, and included diagnostic recommendations from the group’s pathologists. Controversies remain, however, about the morphologic, immunohistochemical, and molecular criteria that should be used to establish a diagnosis of MLA. Herein, the pathologists from the MLA Consortium provide a comprehensive evaluation of the literature on MLA diagnostic criteria, address ongoing controversies in this area, and provide practical guidance for pathologists considering this entity.

Histotype and Grade Are of Prognostic Significance in the No Specific Molecular Profile Molecular Subtype of Endometrial Carcinoma But Not in POLEmut, MMRd, or p53abn Endometrial Carcinomas: Results From a 2478 Case Series and a Systematic Review of the Literature

Histotype and grade of endometrial carcinoma (EC) have been cornerstones of risk assessment, as both are known to be associated with differences in prognosis. The aim of this study was to analyze the prognostic significance of grade and histotype (comparing low-grade endometrioid, high-grade endometrioid, serous, and all others) within each EC molecular subtype, with further stratification by stage. A cohort of 2478 patients with EC were identified from our center. Disease-specific survival was compared for tumors of each molecular subtype after stratification of patients into 1 of 4 groups (low-grade endometrioid, high-grade endometrioid, serous, other). In addition, a systematic review of the literature was undertaken to identify all previous studies where the prognostic significance of grade and histotype within molecular subtypes was reported. Grade and histotype were not of prognostic significance in POLEmut or p53abn EC across all stages and when just considering stage I ECs. MMRd low-grade ECs were associated with a better prognosis; however, they were also associated with lower stage disease, and within stage I tumors, grade and histotype were not of prognostic significance. Grade and histotype were of prognostic significance in NSMP ECs, in all stages and in the subset of stage I tumors (P<0.001 for both analyses). On a systematic review of the literature, we identified 7 studies; there was no prognostic significance of grade and histotype (comparing low-grade endometrioid, high-grade endometrioid and serous) in POLEmut, and p53abn EC, and no prognostic significance of grade and histotype independent of stage in MMRd. Histotype and grade are strongly associated with prognosis in NSMP EC, but not in other molecular subtypes.

Molecular Subtype and Mutational Profile of Endometrial Atypical Hyperplasia/Endometrioid Intraepithelial Neoplasia

Endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia (EAH/EIN) is the acknowledged precursor of most endometrial carcinomas. Our aim was to assess the molecular alterations and the 4 specific molecular subtypes in EAH/EIN diagnosed on endometrial biopsy. Forty EAH/EIN biopsies were stained for estrogen receptor (ER), mismatch repair (MMR) proteins (PMS2 and MSH6), and p53 and were subjected to genomic testing (NGS Panel, Canexia Health V5). Based on these results, cases were assigned to 1 of 4 molecular subtypes [ POLE mut, MMRd, p53abn, and no specific molecular profile (NSMP)]. Follow-up data was collected. There was 1 POLE mut case with a pathogenic POLE mutation (P286R), 5 were MMRd, 1 was p53abn, and the remaining 33 were NSMP. Thirty-nine of 40 cases harbored one or several mutations known to be associated with endometrial carcinoma pathogenesis ( PIK3CA, PTEN , and CTNNB1 ). On follow-up, there was carcinoma or EAH identified in a subsequent hysterectomy or biopsy in 6 of 6 patients with MMRd or p53abn EAH, compared with 19 of 34 with NSMP or POLE mut ( P =0.067). Most EAH/EIN (33/40, 81.5%) are of the NSMP molecular subtype. Molecular subtypes other than NSMP (eg, POLE mutation, MMR deficiency, and p53 mutant pattern staining) are present in EAH/EIN but are less common than in carcinoma. Mutations associated with EC pathogenesis were identified in 39/40 (97.5%) biopsies containing EAH/EIN, highlighting the neoplastic nature of this lesion and raising the possibility of using sequencing (NGS) as an adjuvant test to support a diagnosis of EAH/EIN.

SOX17 Expression in Mesotheliomas and Benign Mesothelial Proliferations: Implications for Differential Diagnosis With Gynecologic Carcinomas

SOX17 has recently emerged as a novel immunohistochemical marker for cancers of endometrial and ovarian origin with improved specificity compared with the widely used Mullerian marker PAX8. However, evaluation of SOX17 in benign and malignant peritoneal mesothelial proliferations remains limited, and these may mimic gynecologic carcinomas, particularly on small biopsies. We evaluated SOX17 and PAX8 expression in 20 benign mesothelial lesions (5 adenomatoid tumors, 5 well-differentiated papillary mesothelial tumors, and 10 peritoneal inclusion cysts) and 16 epithelioid peritoneal mesotheliomas. The 17 female and 3 male patients with benign mesothelial lesions ranged from 20 to 80 yr (median: 56.5 yr), while the 9 females and 7 males with mesothelioma ranged from 47 to 85 yr (median: 57.5 yr). SOX17 was positive in 5 (25%) benign lesions (2 adenomatoid tumors, 3 peritoneal inclusion cysts) and 2 (13%) mesotheliomas, while PAX8 stained 8 (40%) benign lesions (1 adenomatoid tumor, 1 well-differentiated papillary mesothelial tumor, 6 peritoneal inclusion cysts), and 2 (13%) mesotheliomas. Results for the 2 stains showed incomplete concordance, with agreement in 15 (75%) benign proliferations and 14 (88%) mesotheliomas. Our findings suggest that SOX17 positivity alone is insufficient to confirm a diagnosis of gynecologic carcinoma over a mesothelial proliferation and pathologists should exercise caution when these entities are diagnostic considerations.

Lamin A and Emerin Protein Expression Remains Consistently Low and Nuclear Size is Unchanged in Normal Endometrium, Precancerous Lesions, and Endometrioid Carcinoma

Nuclear laminar or inner nuclear membrane proteins, including lamin A, B1, and B2 and emerin, are involved in maintaining nuclear morphology. However, their expression patterns vary among tumors and remain incompletely understood. Endometrioid carcinoma (EC) exhibits mild nuclear atypia, although the underlying reasons have not been thoroughly explored. In this study, we quantitatively analyzed emerin and lamin A, B1, and B2 expression levels in normal endometrium (NE), precancerous lesions, and EC using computer-assisted image analysis to assess the proteins’ roles in nuclear morphologic change during tumorigenesis. From NE to EC, nuclear size remained unchanged, and lamin A and emerin were consistently expressed at low levels, whereas lamin B1 and B2 expression gradually decreased. Given the association between lamin A and emerin as well as their roles in nuclear morphology, these results indicate that their consistent low expression may underlie the preservation of nuclear size and shape in EC relative to NE. Conversely, lamin B1 and B2 are implicated in tumor progression rather than nuclear morphology maintenance. As lamin A and emerin are expressed in many organs and tumors, the consistently low expression of these proteins from NE to EC highlights a notable feature of the endometrium and endometrial carcinogenesis.

Bilateral Somatically Derived Germ Cell Tumors With 12p Gains Arising in High-grade Serous Carcinomas of the Ovary: A Case Report and Review of the Literature

Epithelial ovarian neoplasms are commonly observed in older patients, while germ cell tumors (GCTs) typically present in young individuals. When GCTs are detected in patients over 35 yrs old, they often have an associated epithelial component, a phenomenon known as somatically derived GCTs. We report a unique case of mixed GCT involving bilateral ovaries with a background of high-grade serous carcinoma, including a yolk sac tumor and choriocarcinoma in the mixed GCT component. Somatically derived GCTs are rare with only 45 cases of ovarian carcinoma with somatic yolk sac tumor reported to date. Pathologists face diagnostic challenges in identifying somatically derived GCTs, as they can mimic high-grade epithelial neoplasms. Somatically derived GCTs have poor outcomes, therefore, precise diagnosis is crucial for prognostic and therapeutic considerations.

Validation of Tumor Budding as a Prognostic Factor in Ovarian Clear Cell Carcinoma Using an Independent Cohort

Ovarian clear cell carcinoma (OCCC) is an endometriosis-related neoplasm, in which traditional histologic grading does not show prognostic significance. Tumor budding was associated with poorer outcomes in OCCC in previous studies. We aimed to evaluate the prognostic significance of tumor budding in OCCC in an independent cohort. Seventy patients diagnosed with OCCC were retrospectively identified. Slides from primary ovarian resections were reviewed by 2 pathologists blinded to outcomes. Tumor budding was defined as single or clusters of <5 tumor cells in peritumoral and/or intratumoral nonhyalinized stroma. Most patients were diagnosed at an early stage (stage I: 69%; II: 20%; III: 10%; IV: 1%). Twenty-one patients experienced recurrences (30%) and 2 progressive disease (3%). At the last follow-up, 52 patients had no evidence of disease, 6 were alive with disease, and 12 died of disease. The median follow-up time was 66.7 mo. Tumor budding was identified in 41 cases (59%) with a kappa coefficient of 0.60. On univariate analysis, tumor budding (P=0.022) and stage (P=0.0005) were associated with shorter progression-free survival (PFS), but only stage was independently associated with shorter PFS on multivariate analysis (P=0.003). Higher stage was the only variable associated with shorter overall survival (P=0.037). Tumor budding was associated with higher stage (P=0.039), absence of endometriosis (P=0.042) and adenofibroma (P=0.046), tumor-associated inflammation (P=0.002), and higher mitotic activity (P=0.022). There was no association between tumor budding and molecular characteristics in 32 cases with somatic tumor sequencing. Tumor budding was not independently associated with worse outcomes in this cohort of OCCC, although it was significantly associated with specific clinicopathologic features, including higher stage. Stage was the only independent variable predictive of poorer survival, which appears to drive the prognostic significance of tumor budding.

Morphologic Correlations With Homologous Recombination Deficiency in High-grade Serous Carcinomas

High-grade serous carcinomas (HGSCs) with homologous recombination deficiency (HRD) respond favorably to platinum therapy and poly ADP ribose polymerase (PARP) inhibitors. Mutations in BRCA1 and BRCA2 commonly cause HRD and have been associated with Solid, pseudoEndometrioid, and Transitional-like (SET-like) histology. Mutations in other homologous recombination repair (HRR) genes as well as epigenetic changes can also result in HRD; however, morphologic correlates have not been well-explored in these cases. We hypothesized that HGSCs with HRD, regardless of the etiology, are associated with specific morphologic features. Forty-three cases of HGSC with genomic profiling, which included HRR gene mutation analysis and HRD score, were evaluated. The morphologic patterns, degree of nuclear atypia, necrosis, mitotic index, and tumor-infiltrating lymphocytes (TILs) were determined. The results showed that HRD-high status was significantly associated with the presence of BRCA1/2 mutation, SET-like morphology, geographic necrosis, and severe nuclear atypia. Additional HRR pathway genes with oncogenic mutations identified included ATM, BRIP1, BLM, FANCC, CDK12, CHEK2, RAD51C, and RAD51D. Almost one-third of HRD-high tumors did not have mutations in any HRR pathway genes identified. In conclusion, HGSC with HRD, regardless of BRCA1/2-status, was associated with SET-like morphology and more severe nuclear atypia. Identifying and reporting these patterns of tumor morphology can prompt genomic profiling with prognostic, therapeutic, and genetic counseling implications.

Case Report: ESR1::CITED2 Fusion in a Malignant Uterine Tumor Resembling Ovarian Sex Cord Tumor

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare, typically benign uterine tumor occurring over a wide age range (mean 52.4 yr). UTROSCTs often harbor translocations between ESR1 and nuclear receptor coactivators NCOA1-NCOA3. Here, we present a 21-yr-old woman with a 16 cm complex uterine mass on CT. Grossly, the tumor had an infiltrative appearance. Histologically, it consisted of mild to moderately atypical, spindled cells with ovoid nuclei, growing in fascicles and cords within fibrous to myxohyaline stroma, with tongue-like infiltration of the myometrium. Immunohistochemically, tumor cells were positive for AE1/AE3, ER, PR, vimentin, WT-1, and CD56, and negative for inhibin, calretinin, SMA, desmin, and CD10. Whole exome and whole transcriptome sequencing identified a pathogenic ESR1::CITED2 fusion. The tumor recurred twice (15 and 21 mo after initial surgery) in the abdomen and pelvis. Taken together, the findings suggest this tumor may represent a malignant UTROSCT variant with a novel translocation.

Malignant Brenner Tumor of the Ovary: A Critical Reappraisal

Malignant Brenner tumors (MBTs) are rare epithelial tumors of the ovary, most likely arising from benign and borderline Brenner tumors. MBTs may be misdiagnosed as other primary carcinomas or nonepithelial tumors of the ovary as well as metastatic carcinomas. Accurate diagnosis usually requires clinical-radiologic correlation, extensive sampling, and immunohistochemical studies. Treatment is not standardized and may include surgery with or without chemotherapy. More than half of MBTs are diagnosed at stage I, with 47.7% and at least 20% recurrence and mortality rates, respectively. Awareness of key diagnostic features and pitfalls is essential to differentiate MBT from its mimics and ensure optimal clinical management. This comprehensive review includes classification, etiopathogenesis, historical overview, epidemiology, clinical features, treatment, prognosis, gross pathology, key morphologic features, ancillary testing, and differential diagnostic considerations for ovarian MBTs.

Morphologic Characteristics Seen in High-grade Serous Ovarian Carcinoma Metastases in Postneoadjuvant Chemotherapy Resections

The morphologic features of metastatic high-grade serous ovarian carcinoma (HGSOC) after neoadjuvant chemotherapy have not been described. We conducted a 1-year retrospective, single-institution review of pretreatment biopsy and posttreatment metastases in cases of HGSOC treated with neoadjuvant chemotherapy. Two gynecologic pathologists and 1 pathology resident reviewed 11 cases looking for 6 morphologic features. We correlated these features with patient information on HRD abnormalities (HRD score, germline, and/or somatic BRCA mutations). When compared with the pretreatment biopsies of metastases taken at the time of diagnosis, the postneoadjuvant, treated metastases had unique morphologic findings, such as cytoplasmic vacuolization, cellular enlargement with eosinophilic cytoplasm, macro-nucleoli, cellular discohesion, and micropapillary architecture with abundant psammoma bodies. Metastases were also morphologically different from the primary site in the postneoadjuvant resection specimens.

Origin of Peritoneal Cancer With Features of High-grade Serous Carcinoma: A Detailed Molecular Analysis

Primary peritoneal cancer has characteristics similar to high-grade serous carcinomas of ovarian and fallopian tube origin. However, the relationship between endometriosis and primary peritoneal cancer is not well understood. This study focuses on a case of peritoneal cancer in a patient who had undergone hysterectomy and bilateral salpingo-oophorectomy 5 yr before. In addition to morphology, there was a positive for TP53 in immunohistochemistry and homologous recombination deficiency test, which were similar to high-grade serous carcinomas. However, WT1 was negative in the tumor, and extensive endometriosis coexisted. To reveal the clonal relationship between tumor and endometriosis, we dissected 3 sites each from the tumor and endometriosis and performed whole-exome sequencing analysis. As a result, we found that the tumors were of identical origin. Contrarily, no shared mutations were found in the 3 endometriosis sites. Furthermore, several shared mutations were found between the tumor and 1 endometriosis tissue, showing that the tumor and 1 ectopic endometrial gland originated from the same clone. This study indicates that several peritoneal cancers may be derived from endometriosis. We should consider the possibility of more diverse origins of peritoneal cancer than we speculated before.

Nuclear β-Catenin Expression in the Context of Abnormal p53 Expression Indicates a Nonserous Histotype in Endometrial Carcinoma

The interobserver reproducibility is poor for histotyping within the p53-abnormal molecular category of endometrial carcinomas (ECs); therefore, biomarkers that improve histologic classification are useful. β-catenin has been proposed to have prognostic significance in specific clinicopathologic and molecular contexts. The diagnostic utility for β-catenin expression patterns in determining the histotype of p53-abnormal ECs has not been well studied. We identified ECs molecularly classified as “p53-abnormal.” The p53-abnormal classification was assigned when (1) no POLE exonuclease domain hotspot mutations identified, (2) mismatch-repair protein expression was retained, and (3) abnormal p53 expression (null or overexpression) was present. Morphology was re-reviewed and β-catenin immunohistochemistry was scored as abnormal (nuclear) or normal (membranous, non-nuclear). Eighty ECs were identified in the “p53-abnormal” category; 27 (33.75%) were uterine serous carcinomas, and 53 were of nonserous histotype: 28 uterine carcinosarcomas (35%), 16 endometrioid carcinomas (20%), 2 clear cell carcinomas (2.5%), and 7 high-grade EC with ambiguous morphology (8.75%). All 27 uterine serous carcinomas demonstrated membranous β-catenin staining. Of the 53 nonserous ECs, 11 (21%) showed abnormal β-catenin expression: 6 endometrioid carcinomas, 4 uterine carcinosarcoma, and 1 high-grade EC with ambiguous morphology. The specificity of abnormal β-catenin expression for nonserous EC is high (100%) but the sensitivity is low (21%) with positive and negative predictive values of 100% and 60%, respectively. Our data shows that abnormal β-catenin expression in the context of p53-abnormal EC is highly specific, but not sensitive, for nonserous ECs and may be of value as part of a panel in classifying high-grade EC, particularly to exclude uterine serous carcinoma when nuclear staining is present.

Clinical Significance of Tumor Immune Microenvironment in Endometrial Endometrioid Carcinoma, Grade 1 With DNA Mismatch Repair Protein Loss

The administration of immune checkpoint inhibitors (ICIs) is increasing in endometrial cancer, especially in the mismatch repair (MMR)-deficient group. To prevent unnecessary immune-related adverse events, ICIs need to be administered to more appropriate patients. The tumor immune microenvironment has been reported to be a predictive marker of the efficacy of ICI therapies. This study evaluated CD8, FoxP3, CD68, PD-L1, and β-catenin expression in endometrial endometrioid carcinoma, grade 1 (G1) with DNA mismatch repair protein loss (MMR loss), and their association with clinicopathological features. We retrospectively analyzed tumor samples from 107 patients with endometrial endometrioid carcinoma, G1 (MMR-deficient group: n=67; MMR-proficient group: n=40). Overall, 47 cases of MLH1/PMS2 loss and 20 cases of MSH2/MSH6 loss were observed. The patients with low intraepithelial CD8 expression significantly more frequently exhibited deep myometrial invasion, and the elderly group (≥60 y) significantly more frequently showed low stromal CD8 expression. In addition, FoxP3-positive cell count and FoxP3/CD8+ ratio were significantly correlated with the International Federation of Obstetrics and Gynecology 2023 stage and lymph node metastasis. In the Kaplan-Meier analysis, the patients with low intraepithelial or stromal CD8 expression had shorter progression-free survival (PFS) than those with high intraepithelial or stromal CD8 expression, albeit not significantly. We clarified that the tumor immune microenvironment had an impact on clinicopathological features within the group with MMR loss, which is the main target for ICIs, limited to endometrioid carcinoma, G1. Further studies are needed, including on patients administered ICIs.

The Role of hCG Expression in Endometrial Cancer Prognosis

This study aims to investigate the expression pattern of human chorionic gonadotropin (hCG) in the tissue of endometrioid type endometrial cancer (EEC) using immunohistochemistry, and also to investigate the effect of hCG expression pattern on prognosis and survival in EEC. We evaluated patients who were operated between 2010 and 2020 in the obstetrics and gynecology clinic of our center due to EEC. In total, 194 women were determined to be in either the hCG-negative group (n=137) or the hCG-positive group (n=57). The detection rate of deep myometrial invasion (16.8% vs. 36.8%; P=0.002), lymphovascular space invasion (10.9% vs. 24.6%; P=0.015), and metastatic lymph node (6.7% vs. 21.8%; P= 0.003) in patients with hCG-positive staining were analyzed to be significantly higher. Five-year disease-free survival (DFS) (P= 0.015) and overall survival (OS) (P= 0.024) rates were found to be higher in the hCG-negative group. hCG expression was found to be an independent risk factor for recurrence, and DFS in grade I-II EEC was limited to the uterus and with superficial myometrial invasion (low risk). No independent risk factors for OS were analyzed. hCG positivity is a risk factor with poor prognostic factors in endometrial cancer. It was concluded that hCG expression in low-risk EEC is a valuable negative prognostic factor for recurrence and DFS.

Comparison of Endometrial Serous and Gastric HER2 Immunohistochemistry Scoring Schemes in Endometrial Carcinomas With Aberrant p53 Expression: Reproducibility and In Situ Hybridization Correlation

In 2023, the College of American Pathologists (CAP) supported histotype-specific scoring for HER2 testing in endometrial serous carcinoma based on enrollment criteria for trastuzumab eligibility in the NCT01367002 clinical trial. However, in 2024, the DESTINY-PanTumor02 trial showed the benefit of trastuzumab-deruxtecan in patients with HER2-IHC 2+ and 3+ tumors using CAP gastric scoring, resulting in confusion about how these criteria relate. We compare the results of these scoring schemes by interobserver agreement and correlation with HER2/Chromosome 17 dual in situ hybridization (DISH). Six observers scored 44 HER2-IHC stained p53-abnormal endometrial carcinoma specimens in tissue microarray (TMA) format by endometrial serous (NCT01367002) and gastric systems. Interobserver agreement for HER2 scores (0, 1+, 2+, and 3+) was 81.5% (kappa=0.75) for endometrial serous and 84.6% (kappa=0.79) for gastric scoring. Eight specimens showed discordant HER2 endometrial serous and gastric scores: 4 endometrial serous 1+/gastric 0 and 4 endometrial serous 2+/gastric 3+. HER2-IHC-DISH discordance occurred in 4 specimens by gastric criteria (IHC 3+/DISH negative) and 1 specimen by endometrial serous criteria (IHC 3+/DISH negative). Endometrial serous and gastric HER2-IHC scoring schemes show similar interobserver agreement. In instances of minimal, faint HER2 staining, the endometrial serous score may be 1+ when the gastric score is 0. In instances of limited, strong HER2 staining, the endometrial serous score may be 2+ when the gastric score is 3+. The endometrial serous scheme appears more concordant with DISH results than the gastric scheme, which shows non-infrequent IHC 3+ cases without HER2-DISH amplification. We emphasize recognition of HER2-IHC therapy-specific scoring in endometrial carcinomas, as these scoring systems are similar but not identical.

Molecular Classification of Endometrial Carcinoma: Insights From a Teaching Hospital

Abstract: Endometrial carcinoma is a heterogeneous disease with distinct molecular subtypes that have varied prognosis and therapeutic implications. Since the development of molecular signatures of malignancy is prominent, we are trying to implement this development in our cases of previously diagnosed endometrial cancer. The aim was to determine the prevalence of specific molecular alterations and correlate the genetic profile with the pathologic features and clinical characteristics. We identified 100 cases of endometrial carcinoma, which were eventually classified using immunostains for mismatch repair (MMR) and p53 proteins, in addition to Sanger analysis for POLE gene (Ex, 9, 13, 14). Our findings showed a high prevalence of nonspecific molecular profile (NSMP) in 46 cases (46%), and MMR deficiency in 30 cases (30%). The worst prognosis was observed in the p53 mutant pattern expressed tumors. No statistical difference in pathologic characteristics was observed when the molecular classification was applied. Of note, mutual molecular grouping assignment appears to be present in 5 (5%) of cases of endometrial carcinoma. This is the first study conducted in Saudi Arabia that investigated the prevalence and implications of these molecular subtypes in endometrial carcinoma. The percentage of cases in our result is similar to what had been published globally.

Immunohistochemical Analysis of the Tissue Factor Pathway Inhibitor-2 in Endometrial Clear Cell Carcinoma: A Single-center Retrospective Study

The tissue factor pathway inhibitor-2 (TFPI2) was recently identified as a diagnostic serum marker for ovarian clear cell carcinoma. Moreover, the immunohistochemical expression of TFPI2 in ovarian clear cell carcinoma was recently reported. This single-center retrospective study aimed to evaluate whether TFPI2 can be a specific biomarker for immunohistological diagnosis of endometrial clear cell carcinoma (ECCC). Immunohistochemical staining of TFPI2 in 55 endometrial carcinomas was evaluated at Nara Medical University Hospital. Thirteen ECCC samples were included as cases and 42 samples were included as a control (endometrioid carcinoma grade 1, 11 cases; grade 2, 11 cases; grade 3, 10 cases; serous carcinoma, 10 cases). The mean ± SD TFPI2 histoscore for diagnosing ECCC was 115.4 ± 87.9, which was significantly higher than that of non-ECCC (21.3 ± 45.9, P = 0.002). The best TFPI2 histoscore value obtained from the analyses of receiver operating characteristic curves for immunohistochemical diagnosis of ECCC was 15. With TFPI2 histoscores ≥15.0 as positive and <15.0 as negative, all 13 ECCC cases (100%) were positive for TFPI2, whereas 11 (26.2%) non-ECCC cases were positive for TFPI2. The sensitivity and specificity of TFPI2 for diagnosing ECCC were 100% and 73.8%, respectively. TFPI2 is expressed in ECCC and is useful for histopathological diagnosis.

Uterine MEIS1::NCOA2 Fusion Sarcoma With Lung Metastasis: A Case Report and Review of the Literature

MEIS1::NCOA1/2 fusion sarcomas are a recently described novel entity arising in a variety of locations with a predilection for the genitourinary tract and gynecologic organs. Despite multiple locoregional recurrences, these tumors are thought to behave in a low-grade malignant manner. Here we report a uterine MEIS1::NCOA2 fusion sarcoma with lung metastasis. The patient was a 47-yr-old woman with a history of abnormal uterine bleeding who was found to have a myometrial mass confirmed by pathology to be uterine sarcoma. The tumor was predominantly composed of monotonous spindle cells with scant cytoplasm, crowded nuclei, and brisk mitotic activity, growing in a fascicular and streaming pattern. The morphologic and immunophenotypic features were nonspecific and a diagnosis of high-grade uterine sarcoma with a differential of leiomyosarcoma versus high-grade endometrial stromal sarcoma was rendered. At the 27-mo follow-up, the patient was found to have a lung metastasis consisting of a monotonous round cell sarcoma. A retrospective RNA-based and DNA-based next-generation sequencing of the primary uterine sarcoma revealed a MEIS1::NCOA2 gene fusion, a c.94G>C/p.D32H mutation in exon 3 of CTNNB1 gene, HMGA2, and CDK4 gene amplification, and an intermediate/marginal level of MDM2 gene amplification. Polymerase chain reaction–based molecular analysis further demonstrated that the MEIS1::NCOA2 gene fusion and CTNNB1 somatic mutation were also present in the lung metastasis. This case represents the first case of such gynecologic sarcoma with distant (lung) metastasis, and the second metastatic case among all reported MEIS1::NCOA1/2 fusion sarcomas, highlighting the malignant metastatic potential of this emerging entity. Our case also indicates that HMGA2/CDK4/MDM2 region amplification and CTNNB1 somatic mutation might be recurrent genetic events in this rare sarcoma subtype.

Endometrioid Endometrial Carcinoma With NKX3.1 Expression in a Transgender Man: A Case Report

Endometrial cancer in transgender men is rare, and its histopathologic features remain unknown. A 30-yr-old transgender man with an intrauterine tumor, an ovarian mass, and a 2-yr history of testosterone use was referred to us for treatment. The presence of the tumors was confirmed via imaging, and the intrauterine tumor was identified as an endometrial endometrioid carcinoma via endometrial biopsy. The patient underwent hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and lymph node dissection. Pathologic examination revealed grade 3 endometrioid endometrial carcinoma, and the synchronous endometrial and ovarian tumors were collectively characterized as primary endometrial carcinoma. Metastatic carcinomas were discovered in both ovaries and the omentum, pelvic peritoneum, and a para-aortic lymph node. On immunohistochemistry, the tumor cells diffusely expressed p53, retained expression of PTEN, ARID1A, PMS2, and MSH6, and focally expressed estrogen receptors, androgen receptors, and NKX3.1. NKX3.1 was also expressed in glandular structures within the exocervical squamous epithelium. Prostate-specific antigen and prostatic acid phosphatase were focally positive. In conclusion, we describe a transgender man with NKX3.1-expressing endometrioid endometrial carcinoma who provides valuable suggestions regarding the effects of testosterone on endometrial cancer and appropriate gynecological care for transgender men.

Utility of Morphologic Risk Stratification Modeling and Immunohistochemical Surrogates for Key Molecular Alterations in Uterine Leiomyosarcoma

Accurate diagnosis and prognostic stratification of uterine leiomyosarcoma (LMS) is becoming more important with more nuanced clinical management. Two recent studies by Momeni-Boroujeni and Chapel reported a 7-marker surrogate immunohistochemistry (IHC) diagnostic panel and a morphologic risk stratification schema, respectively. Our objective was to test these approaches in a local cohort. Thirty-four consecutive LMS cases diagnosed at Foothills Medical Center, Calgary, Alberta, Canada (2016–2022) underwent detailed histopathologic review and surrogate IHC panel (TP53, RB1, ATRX, PTEN, DAXX, MTAP, and MDM2). Associations of molecular alterations, morphologic features and survival were studied. Abnormal staining was detected for RB1 (65%), TP53 (62%), ATRX (44%), PTEN (32%), MTAP (15%), DAXX (9%), and MDM2 (6%). Seventy-nine percent of cases showed abnormality in ≥2 molecular markers, confirming a LMS diagnosis. However, 21% of cases showed only one or no abnormality and these cases were associated with a lower nuclear grade and mitotic count, which may cause diagnostic difficulties. While molecular alterations did not predict survival, morphologic risk stratification distinguished low-risk, intermediate-risk, and high-risk groups with significant differences in disease-specific survival (log-rank P = 0.030). While these findings validate the sensitivity of an IHC-based diagnostic panel in confirming the vast majority of LMS diagnoses, a subset, which more likely shows ambiguous diagnostic features, probably requires genomic testing. The previously proposed morphologic criteria seem to provide a robust prognostic stratification.

Prophylactic Risk-reducing Hysterectomies and Bilateral Salpingo-oophorectomies in Patients With Lynch Syndrome: A Clinicopathologic Study of 29 Cases and Review of the Literature

Lynch syndrome (LS) is associated with an increased risk for colorectal, endometrial, and ovarian carcinomas in women. Risk-reducing hysterectomy and bilateral salpingo-oophorectomy (RRHSO) has been shown to be a cost-effective form of management and prevention of gynecological malignancies in patients with LS. Studies of incidental gynecologic malignancies identified in RRHSO are limited. In addition, recommendations on optimal handling of this type of specimen have ranged from submitting for microscopic examination the entire endometrium, fallopian tubes and ovaries to submitting only routine representative sections of these organs. In this study, we present the clinicopathologic findings of 29 cases of LS patients that underwent risk-reducing gynecologic surgery at our institution over a period of 13 yr. Clinical-pathologic information was obtained from the patients’ charts and pathology reports. Significant pathologic abnormalities were identified in 17% (5/29) of cases, all showing endometrial hyperplasia. Four of them with atypical and 1 without atypical. All of our cases with endometrial pathology had significant findings on preoperative endometrial sampling. To further study the recommendation of in toto submission of the endometrium, ovaries and fallopian tubes and the utility of preoperative endometrial sampling, we undertook a literature review of all the reported cases of incidental pathologic findings identified in RRHSO. The findings of our cohort and the literature reviewed support in toto submission of endometrium, and adnexal structures in the absence of gross lesions. In addition, our findings show a definite benefit for preoperative endometrial sampling as part of the workup for LS patients undergoing RRHSO.

From Serous Tubal Intraepithelial Carcinoma to Neuroendocrine Carcinoma: Molecular Dissection of a Rare Fallopian Tube Carcinoma

Primary neuroendocrine carcinoma (NEC) of the fallopian tube is exceptionally rare, with only a small number of cases reported. We report an unusual case in a 77-yr-old woman where a fallopian tube was involved by serous tubal intraepithelial carcinoma (STIC), a small component of high-grade serous carcinoma (HGSC), and a predominant component of small cell neuroendocrine carcinoma (SCNEC). Molecular analysis of microdissected different elements supported a clonal origin, with both tumor components (STIC/HGSC and SCNEC) displaying homologous recombination deficiency and a shared TP53 mutation, while the neuroendocrine component uniquely exhibited 4q deletion and additional DNA repair gene mutations in PALB2 and CHEK2 .

Bilateral Borderline Serous Tumor of Fallopian Tube in a Child With Klippel-Trenaunay Syndrome: An Exceptionally Rare Combination

Klippel-Trenaunay syndrome (KTS) is a rare overgrowth disorder characterized by capillary malformations, vascular anomalies, and limb length discrepancies. It is a congenital, mostly sporadic disorder with unknown pathogenesis, though recent studies have shown an association with somatic mosaic-activating mutations in the PIK3CA gene. The prognosis is variable, depending on the clinical presentation. Visceral involvement in KTS is rare, usually in the form of hemangiomas or venous malformations. Varied neoplastic pathologies have been reported in KTS; however, unlike other overgrowth syndromes, no clear association between KTS and malignancy has so far been elucidated. We report herein an account of a 2-yr-old female child with KTS who presented with abdominal distention and was diagnosed to have a serous borderline tumor (SBT) of bilateral fallopian tubes. Fallopian tube SBT is exceptionally rare and, to the best of our knowledge, has only been reported once previously in a premenarchal patient, who, incidentally, also had KTS. Bilateral fallopian tube involvement in a pediatric SBT has not been described hitherto.

Primary Fallopian Tube Mullerian Adenosarcoma With Sarcomatous Overgrowth and a Previously Unreported MEIS1-NCOA2 Gene Fusion

Extrauterine Mullerian adenosarcomas (MA) are rare and often associated with endometriosis. We report a 55-yr-old patient seen in consultation for abdominal pain and bloating. Imaging was suggestive of a left adnexal mass and “peritoneal carcinomatosis”. Pathological examination of the specimen revealed a MA arising in the left fallopian tube, with sarcomatous overgrowth, diffuse peritoneal involvement and omental “caking”. Next-generation sequencing identified a MEIS1-NCOA2 gene fusion, previously unreported in MA.

Mutational and Immunophenotypic Profiling of a Series of 8 Tubo-ovarian Carcinosarcomas Revealed a Monoclonal Origin of the Disease

Carcinosarcomas are rare, highly aggressive neoplasms composed of a combination of carcinomatous and sarcomatous elements. These tumors represent a paradigmatic field for the study of intratumor heterogeneity. A series of 8 tubo-ovarian carcinosarcomas was characterized for the following: (i) immunohistochemical expression of MNF116, epithelial membrane antigen, vimentin, S100, chromogranin, synaptophysin, desmin, myogenin (MYF4), and p53; (ii) mutational profiling of KRAS, BRAF, PIK3CA, NRAS, TP53, and DICER1 genes. Heterologous differentiation was present in 6 of 8 tumors. Cytokeratin MNF116 and epithelial membrane antigen were positive in all the carcinomatous components and in 87.5% and 50.0% of the sarcomatous components, respectively. The sarcomatous components showed positive staining for vimentin in all cases. Two cases demonstrated positivity for neuroendocrine markers in their carcinomatous components. All rhabdomyosarcomas were positive for desmin and MYF-4. Chondrosarcomas were positive for S100. All but one tumor showed similar p53 immunoreactivity in both the carcinomatous and sarcomatous components, and one case showed cytoplasmic p53 expression. Three of 8 cases (37.5%) showed TP53 mutations, and, in 2 cases, the TP53 mutation was shared by both epithelial and mesenchymal components. DICER1 mutation was found in all components of one case. Mutations in KRAS, NRAS, BRAF, and PIK3CA genes were not found in the study cohort. Our results highlight the heterogeneity of ovarian carcinosarcomas at the phenotypic level. A common mutational signature was observed in both components in 3 of 4 informative tumors. More studies are required to dissect different levels of ovarian carcinosarcomas’ heterogeneity in order to define the best therapeutic approaches to these aggressive neoplasms.

Transtubal Spread of a Superficially Invasive Cervical Adenocarcinoma to the Ovaries After 11 Years

We report a 55-yr-old woman who presented with bilateral ovarian masses, 11 yr after hysterectomy for superficially invasive stage IA1 cervical adenocarcinoma of usual (human papillomavirus–associated) type. The bilateral ovarian tumors were composed of glands lined by malignant mucinous epithelium and these tumors were metastases from her previous cervical adenocarcinoma, based on morphology, immunophenotype, and positive in situ hybridization for human papillomavirus. In addition, there was extensive involvement of the mucosa of the left fallopian tube by malignant mucinous epithelium. The patient is alive and well 2 yr after the ovarian recurrence. The phenomenon of minimally invasive cervical adenocarcinoma metastasizing to the ovary has been described previously; the extrauterine disease is typically limited to the ovaries and associated with a relatively favorable prognosis. The presence of fallopian tube involvement by cervical adenocarcinoma has rarely been reported, and suggests transtubal spread of tumor. Unique to this case is the >11 yr interval between diagnosis of the cervical and ovarian disease, with previously described cases showing up to a 7 yr latency period. This case demonstrates that spread of cervical adenocarcinoma to the ovaries, via the fallopian tube lumen, can occur after a very long latent period and this possibility must be considered when examining adnexal mass(es) in women who have previously had a hysterectomy for cervical adenocarcinoma.

Antibody-drug Conjugate Biomarker Expression in Gestational Trophoblastic Disease: Folate Receptor Alpha, Nectin-4, Trop-2, and Tissue Factor

Antibody-drug conjugates (ADC) are emerging therapies with promising results in the treatment of solid tumors. In this study, we aimed to evaluate biomarker expression of ADCs, including folate receptor alpha (FOLR1), Nectin-4, trophoblast cell surface antigen 2 (Trop-2), and tissue factor (TF) in a diverse cohort of gestational trophoblastic disease. Immunohistochemistry for FOLR1, Nectin-4, Trop-2, and TF was evaluated in tissue microarray of 18 complete hydatidiform moles (CHM) and whole tissue sections of 62 gestational trophoblastic neoplasia (GTN) by 2 gynecologic pathologists. Western blotting for FOLR1, Nectin-4, and Trop-2 was performed in JEG-3 and JAR choriocarcinoma cell lines, 2 CHM and 3 GTN clinical samples. Results: The overall immunohistochemical positive rate in GTN was 11% for FOLR1, 59% for Nectin-4, 38% for Trop-2, and 26% for TF. Choriocarcinomas showed 27% positivity for FOLR1, 75% for Nectin-4, 40% for Trop-2, and 25% for TF. Epithelioid trophoblastic tumors (ETT) were positive for Nectin-4 in 58%, for Trop-2 in 79%, and for TF in 67% of cases. Placental site trophoblastic tumors were positive only for Nectin-4 (23% of cases). In CHM, only Nectin-4 revealed a higher degree of expression and limited staining for the other markers. Western blotting showed FOLR1 expression in CHM, JEG-3, and JAR; Nectin-4 in CHM and PSTT; and Trop-2 in CHM, JEG-3, and choriocarcinoma. Conclusion: A subset of GTN shows expression for FOLR1, Nectin-4, Trop-2, and TF, particularly choriocarcinoma and ETT. These results suggest that patients with GTN could potentially benefit from ADC treatment.

Lymphovascular Space Invasion in Cervical Cancer: A Review of Clinical Significance and Pathologic Issues

Lymphovascular space invasion (LVSI) is defined as tumor cells within blood vessels or lymphatic endothelial-lined spaces and, until recently, its prognostic significance in cervical cancer was somewhat controversial and less well studied than for some other tumor types in the female genital tract. Based on the available literature, there is now strong evidence that LVSI is not only a significant prognostic factor, especially in early-stage cervical cancers (squamous cell carcinomas and adenocarcinomas), but is also a predictive factor for lymph node metastases. Consequently, while LVSI does not impact FIGO or TNM staging, its presence should be recorded in the pathology report and considered in management decisions regarding adjuvant treatment, as suggested by various international guidelines. More recently, the extent of LVSI (substantial vs. focal vs. negative) has been demonstrated to predict survival in cervical cancer, although this is an area where more study is required both to determine whether substantial LVSI is of prognostic significance and to ascertain the optimal definition of substantial LVSI. LVSI can be diagnosed on routine microscopic examination without ancillary tests in most cases and thus can be reported even in low-resource settings. There are, however, various pathologic issues both in diagnosing and quantifying LVSI, with no universal recommendations. In this review, we examine the significance of LVSI in cervical cancer in terms of prognostication and in dictating the need for adjuvant treatment. We also discuss practical issues related to the pathologic reporting of LVSI.

A Trichoadenoma/Trichoepithelioma/Trichoblastoma-like Lesion in the Uterine Cervix Focally Mimics an Adenoid Basal Tumor

The presence of ectodermal adnexal structures in the uterine cervix, including sebaceous glands, hair follicles, and sweat glands, has been well documented in the literature. In theory, there exists the possibility of developing cutaneous-type lesions from the ectopic ectodermal structures in this location. Here we report the first case of cervical hair follicle-derived proliferations reminiscent of trichoadenoma, trichoepithelioma, and trichoblastoma (TA/TE/TB) in a 52-year-old woman who underwent a prophylactic hysterectomy due to a germline microphthalmia-associated transcription factor (MITF) gene mutation. The lesion was an incidental finding in the cervix, exhibiting a spectrum of morphologic features ranging from germinative TB with basaloid cells, to TE with some degree of infundibulocystic differentiation, to well-differentiated TA. In some areas, hair follicle-like structures were associated with sebaceous glands, forming pilosebaceous units. The proliferations in the TB-like area resembled adenoid basal epithelioma/carcinoma; however, ancillary studies, particularly patchy p16 expression and non-detection of HPV, argued against this diagnosis. Similar to adenoid basal tumors, the TB-like lesion focally expressed NKX3.1, suggesting that it might be related to ectopic prostatic tissue or exhibit prostatic-lineage differentiation. While the theory of misplaced embryonal tissue, or an acquired metaplastic process, has been discussed, the histopathologic origin of these lesions remains largely unknown.

TP53 as a Diagnostic Aid in the Distinction of Ovarian Mucinous Borderline Tumors From Mucinous Carcinoma

Ovarian mucinous borderline tumors (MBTs) are clinically managed as benign neoplasms while the management of ovarian mucinous carcinomas (MC) is dependent on tumor stage. Despite the standardization of sampling of ovarian mucinous neoplasms, limited interobserver reproducibility between MBT and MC persists. Based on our recent finding that abnormal TP53 expression is associated with unfavorable outcome in MBT, we hypothesized that TP53 status might improve the reproducible distinction of MBT from MC. A virtual slide set of 85 consecutive ovarian mucinous neoplasms received at a single institution, with each case represented by 3 full sections, were reviewed by 3 pathologists in 2 iterations. The initial assessment was based solely on morphologic review, while the second iteration was performed with knowledge of TP53 status. The reproducibility of a trinary categorization (MBT, MBT with intraepithelial carcinoma [IEC], MC) significantly improved from a κ of 0.60 based on the initial morphologic assessment to a κ of 0.76 (t-test, P=0.0042) after consideration of TP53 immunohistochemistry (IHC) results. Six out of 85 patients died of disease, and in 2 of them, at least 1 pathologist assessed MBT with IEC and not MC even after integration of TP53 IHC. With the integration of TP53 IHC, substantial interobserver agreement for MBT and MC can be reached, particularly in cases with an uncertain degree of confluent growth. TP53 IHC can also be used to highlight and support the presence of IEC in MBT, however, discordances remained in 2 cases with adverse outcome.

Immunohistochemistry and Next-generation Sequencing Are Complementary Tests in Identifying PTEN Abnormality in Endometrial Carcinoma Biopsies

PTEN plays a central role in the pathogenesis of endometrial carcinoma. Previous studies reported a high interobserver reproducibility for the interpretation of PTEN immunohistochemistry (IHC). However, PTEN IHC and its interpretation remain challenging during laboratory practice. The purpose of this study was to reevaluate PTEN IHC pattern in direct comparison to next-generation sequencing in identifying PTEN abnormality. IHC and tagged-amplicon next-generation sequencing PTEN sequencing was performed on 182 endometrial carcinoma biopsy/curetting samples from five centers (Barts, Calgary, Cambridge, Leiden, and Vancouver). Sensitivity, specificity and accuracy of PTEN IHC to predict loss of function PTEN mutations were calculated. Abnormalities of PTEN in association with histotype and molecular subtype were assessed. A total of 5 PTEN IHC patterns were recorded: absent, subclonal loss, equivocal, reduced (relative to internal control) and retained. The absence of PTEN IHC has a sensitivity of 75.4% (95% confidence interval: 62.7–85.5%), a specificity of 84.6% (95% confidence interval: 76.2%–90.9%), and accuracy of 81.2% (95% confidence interval: 74.4%–86.9%) in predicting loss of function PTEN mutation. PTEN abnormality by complementary interpretation of both assays was present in 91.9% of endometrial endometrioid carcinoma, grade 1, and significantly higher in endometrial endometrioid carcinomas of all grades compared with endometrial serous carcinoma (80.0% vs. 19.4%, P <0.0001). PTEN abnormalities are common across all molecular subtypes of endometrioid carcinomas. Our data support the use of ancillary PTEN IHC for diagnostic purposes in endometrial neoplasms. However, for clinical trial design complementary testing of both IHC and sequencing of PTEN should be considered to assess the PTEN status in endometrial carcinomas.

The Morphologic and Molecular Heterogeneity of Fumarate Hydratase–deficient Leiomyomas: Integrative Molecular Profiling of Uterine Smooth Muscle Tumors With Histologic Feature Correlation

The morphologic features of uterine smooth muscle tumors (USMTs) are subject to interobserver variability and are complicated by consideration of features of fumarate hydratase deficiency (FHd) and other morphologic subtypes, with difficult cases occasionally diagnosed as smooth muscle tumor of uncertain malignant potential (STUMP). We compare immunohistochemical findings and detailed morphologic analysis of 45 USMTs by 4 fellowship-trained gynecologic pathologists with comprehensive molecular analysis, focusing on FHd leiomyomas (n=15), compared to a variety of other USMTs with overlapping morphologic features, including 9 STUMPs, 8 usual-type leiomyomas (ULM), 11 apoplectic leiomyomas, and 2 leiomyomas with bizarre nuclei (LMBN). FHd leiomyomas, defined by immunohistochemical (IHC) loss of FH and/or 2SC accumulation, showed FH mutations and/or FH copy loss in all cases, with concurrent TP53 mutations in 2 tumors. Severe and/or symplastic-type cytologic atypia was seen more often in FHd leiomyomas with only FH copy loss (6/8, and 2/2 with concurrent TP53 mutations) compared to those with FH mutations (2/7) and typically showed increased genomic instability. This subset of FHd tumors often showed morphologic overlap with STUMPs and LMBN, but all cases of FHd tumors showed 2SC accumulation and/or FH loss by IHC. In conclusion, we highlight the importance of investigating USMTs with severe and/or symplastic-type cytologic atypia with FH and 2SC IHC, as many of these tumors are FH-deficient via focal deep deletion (2-copy loss) of the FH locus. In addition, we report the presence of concurrent TP53 mutations in FHd tumors with more severe cytologic atypia; further data about clinical outcomes for these tumors are needed.

Molecular and Clinicopathologic Characterization of HER2-overexpressed Squamous Cell Carcinoma of the Cervix

HER2 amplification in cervical cancer has been associated with worse clinical prognosis and a potential favorable response to HER2 inhibitors. Immunohistochemistry for the HER2 receptor is a universally accepted surrogate test for HER2 amplification, but no standardized scoring system currently exists for cervical carcinomas. In this study, we investigated HER2 overexpression in cervical squamous cell carcinoma and correlated it with HER2 amplification using fluorescence in situ hybridization (FISH) and molecular methods. Seventy-two cases of human papillomavirus-associated cervical cancer were retrospectively reviewed, and at least 2 representative tumor sections were stained for HER2. HER2 scoring was performed using the 2018 American Society of Clinical Oncology/College of American Pathologist breast cancer criteria, and cases with equivocal (2+) to positive (3+) expression were analyzed for HER2 amplification using FISH and next-generation sequencing. The average patient age was 50 yrs (range: 27–85 yr), with most patients being African American (73.6%) and diagnosed at FIGO stage I (65.3%). Nineteen (26.4%) had equivocal HER2 expression and 4 (5.5%) showed positive expression. Three of the 4 cases with positive expression had enough tumors for FISH, and all 3 were amplified. Three cases with equivocal expression showed HER2 polysomy on FISH, and none showed HER2 amplification. Late clinical stage, high tumor grade, and regional lymph node metastasis were significantly correlated with HER2 overexpression and HER2 amplification. Next-generation sequencing of the 3 HER2-amplified tumors showed amplification of various genes, including CD274, JAK2, BIRC3, and ERBB2, and a PIK3CA missense mutation. In summary, HER2 immunohistochemistry is a reliable predictive marker of HER2 amplification in cervical cancer.

Two Rare Cases of Paratubal Leydig Cell Nodules: Clinical Relevance and Debated Terminology of a Noteworthy Incidentaloma

Cells with cytologic and immunohistochemical features of Leydig cells are normally present in the ovary and the ovarian hilum, are testosterone-producing, and have been referred to as ovarian hilus cells. Rarely these cells form nests or nodules in extraovarian sites such as the mesovarium or mesosalpinx. Because they are so rare, these nodules can present a diagnostic challenge when first encountered. This report describes 2 such incidental nodules in the mesosalpinx associated with a small paratubal cyst and suggests that the term Leydig cell nodule be preferred over the nonspecific and confusing historical term ovarian hilus cell nest.

Clinicopathologic Review of Metastatic Breast Cancer to the Gynecologic Tract

Metastatic spread is the single most significant predictor of poor survival in breast cancer. Some of the most common metastatic sites are the bones, lungs, liver, brain, and peritoneal cavity. Clinically metastatic breast cancer to the gynecologic tract is usually asymptomatic and diagnosed as an incidental finding during a histologic examination of gynecologic specimens resected for other reasons. Cases of metastatic breast cancer to gynecologic organs diagnosed from August 1995 to January 2021 were retrieved from our institution’s pathology databases, and their clinicopathologic features were reviewed. The most common site of metastasis was the ovary which was involved in about 79% (22 of 28 cases) of metastases to the gynecologic tract. Clinically, only 8 cases (36%) presented with ovarian mass detected in imaging studies and the rest of the cases were all incidental findings. Among ovarian metastasis, 59% of cases were invasive lobular carcinoma and 41% were invasive ductal carcinoma. In 5 cases, metastatic breast cancer was found in the endometrium, including 2 cases with endometrial metastasis only and 3 cases with multiple gynecologic organs involved. Metastatic breast cancer rarely involved the lower gynecologic tract, with only 7% vaginal metastasis and 4% found in the vulva. The absolute majority of metastatic breast cancer outside of the ovaries were lobular carcinoma (88%). Most of the metastatic breast carcinomas were positive for estrogen receptor on immunohistochemistry (27 of 28 cases, 96%). Her-2/neu immunostaining was positive in 4 cases only (14%). Metastatic breast cancer needs to be distinguished from gynecologic primary neoplasms and metastatic tumors from adjacent urinary and GI tracts. A careful review of the patient’s history and adequate immunohistochemistry panel are helpful to render the diagnosis.

HPV-negative Tumors in a Swedish Cohort of Cervical Cancer

Despite the common perception that the human papilloma virus (HPV) is a requirement for the development of cervical cancer (CC), a considerable number of CCs test HPV negative. Presently, many countries are shifting to HPV primary CC screening, and it is of importance to increase the knowledge about the group of CCs that test HPV negative. The aim of this study was to reinvestigate a proportion of cervical tumors with a primary negative or invalid test result. Reinvestigation with repeated genotyping (targeting L1) was followed by analysis with an alternative target method (targeting E6/E7) on existing or additional tumor material. Consistently negative tumors were histologically evaluated, and cases with low or lacking tumor cell content, consistent invalid test results, or with suspicion of other than cervical origin were excluded. HPV-negative cases were thereafter subjected to immunohistochemistry (Cytokeratin 5, pan cytokeratin, protein 63, P16, and P53). The HPV-negative proportion could after reinvestigation be reduced by one-half (14%–7%). Additional positive samples were often detected in late polymerase chain reaction cycles, with an alternative (E6/E7) or the same (L1) target, or with a method using shorter amplicon lengths. Confirmed HPV negativity was significantly associated with worse prognosis, high patient age, longer storage time, and adenocarcinoma histology. Some of the HPV-negative cases showed strong/diffuse p16 immunoreactivity, indicating some remaining false-negative cases. False HPV negativity in this cohort was mainly linked to methodological limitations in the analysis of stored CC material. The small proportion of presumably true HPV-negative adenocarcinomas is not a reason for hesitation in revision to CC screening with primary HPV testing.

Confusing Histopathological Features and HPV Testing Results in Vulvar Squamous Cell Carcinoma Arising in a Young Woman: A Case Solved Using Next-Generation Sequencing

Vulvar squamous cell carcinoma (VSCC) can be classified according to human papillomavirus (HPV) status as HPV-associated (HPV-A) and HPV-independent (HPV-I). However, a small subset of tumors may show overlapping features and become a serious diagnostic challenge for pathologists. We report an unusual case of VSCC arising in a 21-year-old patient with type 1 diabetes mellitus. The tumor had keratinizing histologic features, was associated with a premalignant lesion with features of a high-grade squamous intraepithelial lesion (HSIL), and showed consistent p53 immunohistochemical (IHC) overexpression, but variable results in the HPV testing and p16 IHC staining. Molecular analysis revealed mutation of TP53 and overexpression of cell cycle-regulating genes (including CCND1) and collagen-coding genes (such as COL6A1). These molecular findings in genes, previously reported as upregulated in HPV-I VSCC, supported an etiological origin independent of HPV for the tumor. In conclusion, molecular analysis may help to correctly classify challenging VSCC, showing puzzling clinical, morphologic, and IHC characteristics.

Does “One Size Fits All”? Rethinking FIGO Depth of Invasion Measurements in Vulvar Cancer

Depth of invasion (DOI) is an important diagnostic parameter in patients with vulvar carcinoma, where a cutoff value of 1 mm largely determines the tumor stage and the need for groin surgery. DOI measurement should be reproducible and straightforward. In light of the new recommendation on how to measure DOI in the International Federation of Gynecology and Obstetrics (FIGO) staging system 2021, an exploratory study was conducted on the current practice of DOI measurement in vulvar cancer. In this study of 26 selected cases, 10 pathologists with high exposure to vulvar cancer cases in daily practice assessed both the conventional (FIGO 2009) and alternative (FIGO 2021) DOI methods for applicability and preference. In this set of cases, the DOI measurement according to FIGO 2009 was generally considered easier to apply than the measurement according to FIGO 2021, with applicability being rated as “easy to reasonable” in 76.9% versus 38.5% of cases, respectively (P=0.005). The preferred method was FIGO 2009 or tumor thickness in 14 cases and FIGO 2021 in 6 cases. No invasion was preferred in 1 case. For the remaining 5 cases, half of the pathologists opted for the FIGO 2009 method and half for the FIGO 2021 method. Although the FIGO 2009 method proved to be more readily applicable in most of the cases studied, the method may differ for each case. There may not be a “one size fits all” solution for all cases of vulvar cancer.

Grading of Endocervical Adenocarcinomas: Review of the Literature and Recommendations From the International Society of Gynecological Pathologists

There is a lack of consensus regarding the prognostic value of grading endocervical adenocarcinomas and currently, no universally applied, validated system for grading exists. Several grading schemes have been proposed, most incorporating an evaluation of tumor architecture and nuclear morphology and these are often based on the International Federation of Gynecology and Obstetrics (FIGO) system for endometrial endometrioid carcinoma, although some schemes modify the proportion of solid tumor required to separate grades 1 and 2 from 5% to 10%. In the absence of a validated system, we endorse this approach for most human papillomavirus–associated endocervical adenocarcinomas and, based on the available evidence, recommend that tumors with ≤10% solid growth be designated grade 1, 11% to 50% solid growth grade 2 and >50% solid growth grade 3. Tumors should be upgraded in the presence of marked nuclear atypia involving the majority (>50%) of the tumor. Grading is not recommended for human papillomavirus-independent adenocarcinomas, since no validated system has been suggested and most of these neoplasms exhibit intrinsically aggressive behavior regardless of their morphologic appearance. Importantly, grading should not be performed for gastric-type adenocarcinomas, particularly as these tumors may appear deceptively “low-grade” yet still exhibit aggressive behavior. Recently devised, validated and reproducible etiology and pattern-based tumor classification systems for endocervical adenocarcinomas appear to offer more effective risk stratification than tumor grading and, in the future, these systems may render the provision of a tumor grade redundant.

β-catenin, PAX2, and PTEN Aberrancy Across the Spectrum of Endometrioid Ovarian Lesions

Endometriosis is a common condition, with the ovary being the most common anatomic site. Endometriosis—particularly in the ovary—is associated with a risk of malignant progression, with a histologic spectrum of lesions from benign to malignant. Recently, a panel of 3 markers consisting of β-catenin, PAX2, and PTEN has been described as a potentially useful diagnostic adjunct in the diagnosis of intrauterine endometrioid neoplasia, where aberrancy for one or more of the markers is strongly associated with neoplasia. Here, we applied the panel to ovarian endometrioid lesions, including endometriosis, endometriosis with flat cytologic atypia, endometrioid borderline tumors, and endometrioid adenocarcinoma (n=85 cases in total). The incidence of aberrancy for the 3 markers increased along this putative neoplastic spectrum, arguing for a role of each of the markers in the neoplastic transformation of ovarian endometriosis. Just 1/32 (3%) of cases of nonatypical endometriosis was marker-aberrant, and this case was aberrant only for PAX2. One of 5 cases (20%) of endometriosis with atypia was marker-aberrant (both PAX2 and PTEN), supporting prior findings that some cases of flat atypia may represent bona fide precursor lesions. Of 19 endometrioid borderline tumors, 10 (53%) were aberrant for one or more markers, with PAX2 being the most frequently aberrant. Of 29 endometrioid adenocarcinomas, 28 (96.6%) were aberrant for at least 1 marker, with PAX2 again the most frequently aberrant. Patterns of aberrancy were well-preserved in areas of nonatypical endometriosis adjacent to borderline tumor or adenocarcinoma, supporting a biological origin in a common marker-aberrant precursor. The findings show that the biomarker panel could be of some diagnostic utility in the characterization of ovarian endometrioid neoplasia, such as in the diagnosis of endometrioid borderline tumor, distinguishing endometrioid from nonendometrioid lesions, or in identifying other types of early precursors at a higher risk of malignant transformation.

Endometrial Carcinosarcomas are Almost Exclusively of p53abn Molecular Subtype After Exclusion of Mimics

Summary Our aim was to assess the molecular subtype(s) and perform a detailed morphologic review of tumors diagnosed as carcinosarcoma in a population-based cohort. Forty-one carcinosarcomas were identified from a cohort of 973 endometrial carcinomas diagnosed in 2016. We assessed immunostaining and sequencing data and undertook expert pathology reviews of these cases as well as all subsequently diagnosed (post-2016) carcinosarcomas of no specific molecular profile (NSMP) molecular subtype (n=3) from our institutions. In the 2016 cohort, 37 of the 41 carcinosarcomas (91.2%) were p53abn, 2 (4.9%) were NSMP, and 1 each (2.4%) were POLEmut and mismatch repair deficiency molecular subtypes, respectively. Of the 4 non-p53abn tumors on review, both NSMP tumors were corded and hyalinized (CHEC) pattern endometrioid carcinoma, the mismatch repair deficiency tumor was a grade 1 endometrioid carcinoma with reactive stromal proliferation, and the POLEmut tumor was grade 3 endometrioid carcinoma with spindle cell growth, that is, none were confirmed to be carcinosarcoma on review. We found 11 additional cases among the 37 p53abn tumors that were not confirmed to be carcinosarcoma on the review (3 undifferentiated or dedifferentiated carcinomas, 5 carcinomas with CHEC features, 2 carcinomas showing prominent reactive spindle cell stroma, and 1 adenosarcoma). In the review of institutional cases reported as NSMP carcinosarcoma after 2016, 3 were identified (1 adenosarcoma and 2 mesonephric-like adenocarcinoma on review). In this series, all confirmed endometrial carcinosarcomas were p53abn. The finding of any other molecular subtype in a carcinosarcoma warrants pathology review to exclude mimics.

Morphomolecular Correlation and Clinicopathologic Analysis in Endometrial Carcinoma

Research groups have identified 4 groups [polymerase epsilon (POLE) mutant, mismatch repair-deficient, p53-abnormal, and no specific molecular profile)] reflecting the Tumor Cancer Genomic Atlas Research Network subgroups in endometrial carcinomas, improving the clinical applicability of molecular classification. We have analyzed the histopathologic and prognostic characteristics of our cases based on the ProMisE classification, supported by growing data on recommended treatment regimens. The study included 118 cases of endometrial carcinoma diagnosed between 2016 and 2020, which underwent mismatch repair and p53 immunohistochemistry. Next-generation sequencing was performed for POLE mutation analysis, dividing the cases into 4 subgroups. The histopathologic and clinical characteristics of these groups were then analyzed statistically. Four cases(3.4%) were classified as POLE mutant, 31 (26.3%) as mismatch repair-deficient, 22 (18.6%) as p53 mutant, and 61 (51.7%) as no specific molecular profile. We categorized 118 patients with endometrial carcinoma into low (n=43), intermediate (n=28), high-intermediate (n=21), high (n=22), and advanced metastatic (n=4) risk groups regardless of the molecular subtypes of their disease. When we reclassified all cases according to the molecular subtypes of endometrial carcinoma only the risk group of 3 (2.5%) cases changed. Using the new algorithm we designed, after narrowing down the number of patients, the microcystic, elongated, and fragmented pattern of invasion was revealed as an independent prognostic factor that reduces overall survival time (hazard ratio: 16.395, 95% CI: 2.140–125.606, P=0.007). In conclusion, using the new algorithm we have designed, and by identifying patients for whom molecular classification could alter risk groups, we observed that molecular tests can be utilized more efficiently in populations with limited economic resources and, in doing so, we discovered a new morphologic marker with prognostic significance.

Comprehensive Immunohistochemical Analysis of Mesonephric Marker Expression in Low-grade Endometrial Endometrioid Carcinoma

Immunohistochemical markers shown to be useful in identifying/confirming mesonephric/mesonephric-like differentiation (MLD markers) include thyroid transcription factor (TTF1), GATA-binding protein 3 (GATA3), and cluster of differentiation 10 (CD10). Only a few studies have examined the expression levels of MLD markers in endometrial endometrioid carcinomas (EECs). This study aimed to analyze the frequency and pattern of MLD marker expression in low-grade EECs. We performed immunostaining for the detection of TTF1, GATA3, and CD10 expression in 50 low-grade EEC tissue samples and evaluated their staining proportion and intensity. Nine tumors (18.0%) expressed at least one MLD marker in varying proportions and intensities, and 2 of these tumors were positive for 2 MLD markers (TTF1/GATA3 and GATA3/CD10, respectively). Three (6.0%) tumors showed moderate-to-strong nuclear TTF1 immunoreactivity in ≤5% of the tumor cells. Five tumors (10.0%) had at least moderate nuclear GATA3 staining, and three of them displayed a staining proportion of ≥15%. Three tumors (6.0%) were focal (mean proportion, 15%) but strongly positive for CD10. Our findings indicate that a subset of EEC can express one or more MLD markers with varying staining proportions and intensities. Given that a diagnosis of uterine mesonephric-like adenocarcinoma should be established based on a combination of characteristic histologic features, unique immunophenotypes, and confirmed molecular findings, pathologists should not exclude EEC based only on the presence of focal immunoreactivity for MLD markers. Awareness of the atypical expression patterns of MLD markers in EEC helps pathologists avoid misdiagnosing EEC as a uterine mesonephric-like adenocarcinoma.

Clinicopathological and Molecular Characterization of High Grade Endometrial Carcinomas of No Specific Molecular Profile (NSMP) Stratified by ER Status

This study represents a omprehensive characterization of high-grade endometrial carcinoma (EC) of no specific molecular profile (NSMP) to improve our understanding of their poor clinical outcome. A previously molecularly classified cohort of 412 high-grade EC from the Danish Cancer Registry was extensively reviewed by 2 expert pathologists blinded for associated clinical and molecular data. Immunohistochemistry (IHC) was performed to determine ER, PR, and L1CAM status and a 10% cut-off value was applied for positivity. Shallow whole-genomic sequencing (sWGS) and next-generation sequencing (NGS) was performed to describe the molecular landscape. Survival analysis was performed using the Kaplan-Meier method, and survival difference was tested using the log-rank test. Of the 57 high-grade NSMP tumors, ER negativity was found in 30 (53%). All clear cell NSMP EC (n=12, 21%) were ER negative. L1CAM overexpression was found in 29 high-grade NSMP EC (53%) and showed overlap (n=20, 69%) with ER negativity. A high frequency of copy number (CN) events and fraction genome altered (FGA) was observed, with the median number of CN events clustering by ER status (28 vs. 43, P <0.05). Overall, the cohort showed a 52% (CI: 31.6%, 72.4%) 5-yr overall survival (OS) and 61% (CI: 42.6%, 79.4%) 5-yr disease-specific survival (DSS). No significant additional prognostic refinement was found when stratifying for ER status (5-yr OS: 46% vs. 65%, P =0.068). High-grade NSMP ECs are a heterogenous group of tumors with high prevalence of loss of ER, L1CAM overexpression, and substantial copy number alterations. Within this group, no prognostic effect of ER was identified, providing support for grouping these tumors into one risk group. This work adds to the growing body of evidence that both high-grade and/or loss of ER expression can be used to identify NSMP EC patients with a poor clinical outcome.

PIM1 is a Poor Prognostic Factor for and Potential Therapeutic Target in Serous Carcinoma of the Endometrium

Serous carcinoma (SC) is an aggressive histologic type of endometrial carcinoma (EMC) with a poor prognosis. The development of novel therapeutics for SC is an important issue. PIM1 is a serine/threonine kinase involved in various cellular functions, such as cell cycle progression, apoptosis, and transcriptional activation via the phosphorylation of many target proteins, including MYC. PIM1 is overexpressed in several cancers and has been associated with treatment-resistance. We investigated the expression and function of PIM1 in EMC, particularly SC. Immunohistochemical analysis in 133 EMC cases [103 endometrioid carcinomas (EC) and 30 SC] revealed the significantly stronger expression of PIM1 in SC than in EC and significantly shorter survival of patients with overexpression of PIM1 in all EMC cases, as well as in only SC cases. A multivariate analysis identified overexpression of PIM1 as an independent prognostic factor. The knockdown of PIM1 by siRNA in the SC cell line, ARK1, decreased the expression of phosphorylated MYC and reduced proliferation, migration, and invasion. The PIM1 inhibitor, SGI-1776, reduced cell viability in SC cell lines (ARK1, ARK2, and SPAC1L) with IC50 between 1 and 5 µM. SGI-1776 also reduced the migration and invasion of ARK1 cells. Moreover, the oral administration of SGI-1776 significantly suppressed subcutaneous ARK1 xenograft tumor growth in nude mice without impairing health. These results indicate that PIM1 is involved in the acquisition of aggressiveness and suggest the potential of PIM1 as a novel therapeutic target and SGI-1776 as a therapeutic agent for SC.

Serous Tubal Intraepithelial Carcinoma After Neoadjuvant Chemotherapy: A Report of 2 Cases

Serous tubal intraepithelial carcinoma (STIC) is regarded as the origin of most high-grade serous carcinomas (HGSC). After a diagnosis of isolated STIC, risk of developing HGSC is substantial. Since surveillance cannot detect HGSC in time to cure the disease, there is no consensus on the optimal treatment after a diagnosis of isolated STIC, but chemotherapy is considered one of the possible strategies. In this case report, we describe 2 women with advanced-stage HGSC treated with 3 cycles of neoadjuvant chemotherapy followed by interval debulking surgery. In both women, histopathological examination showed a complete histopathological tumor response, but a vital STIC was found in both cases. The 2 cases presented here indicate that STICs may not respond to chemotherapy. Further research focused on the underlying biology and chemosensitivity of STIC, as well as the effectiveness of treatment to prevent HGSC in case of isolated STIC, is needed.

A Case of NTRK Fusion Corpus Sarcoma With Pseudobiphasic Growth Pattern and Literature Review

The incidence of neurotrophic tyrosine kinase receptor (NTRK) fusion uterine sarcoma is extremely low, and reports have been mostly focused on cases localized to the cervix. So far, only 4 cases have been reported of the uterine corpus. In this study, we reported a case of NTRK fusion corpus sarcoma. This study aimed to expand the morphologic spectrum of this tumor, which showed adenosarcoma-like features not previously described. The tumor was confined to the uterine corpus, polypoid growth, comprised predominantly of a fascicular proliferation of spindle cells, entrapping benign endometrial glands, and exhibited a pseudo-biphasic growth pattern. The tumor showed coexpression of S-100, CD34, and pan-Trk by immunohistochemistry, DNA-sequencing identified TPR-NTRK1 gene fusion and AKT1(E17K) mutation. Four cases of NTRK fusion corpus sarcoma were reviewed. The clinicopathologic features, immunohistochemical phenotype, molecular testing, and prognosis of 5 cases including this one were summarized and analyzed. Most cases exhibited an infiltrative growth pattern and showed mild or moderate cytologic atypia. The potential for these tumors to be misclassified as uterine adenosarcoma or other uterine mesenchymal tumors. The diagnosis relies on pan-Trk, S-100, CD34 immunohistochemistry, and molecular testing. Surgical resection is the mainstay of treatment for most patients. Distinguishing these tumors from morphologic mimics is significant because patients with advanced-stage disease may be treated with TRK inhibitors.

LINE-1 ORF1p is a Promising Biomarker in Cervical Intraepithelial Neoplasia Degree Assessment

Cervical intraepithelial neoplasia (CIN) represents a spectrum of preinvasive squamous lesions within the cervical epithelium, whose identification is a diagnostic challenge due to subtle histomorphological differences among its categories. This study explores ORF1p, a nucleic acid-binding protein derived from long interspersed nuclear element-1 (LINE-1), as a potential biomarker for enhancing CIN diagnosis. A comprehensive analysis of 143 cervical specimens, encompassing CIN I (n=20), CIN II (n=46), CIN III (n=14), invasive cancer (n=32), and nondysplastic cases (normal cervical epithelia (n=24) and atrophy (n=7) were conducted. ORF1p, Ki67, and p16 expressions were evaluated using immunohistochemistry. ORF1p immunopositivity was detected in the vast majority [110/112 (98.2%)] of dysplastic and neoplastic (CIN and invasive cancer) specimens, whereas 19/24 (79.2%) of normal cervical specimens lacked ORF1p expression. The observed pattern of ORF1p expression showed a progressively increasing extent and intensity with advancing CIN grades. CIN I exhibited mild ORF1p expression in the lower one or two-thirds of the cervical epithelium [14/16 (87.5%)], whereas CIN II demonstrated moderate to strong ORF1p expression spanning the lower two-thirds [29/46 (63.0%)]. Pronounced transepithelial ORF1p immunopositivity characterized CIN III cases [13/14 (92.8%)] and cervical cancer [30/32 (93.8%)]. These findings propose ORF1p as a valuable indicator even for detecting CIN I, effectively discerning them from normal cervical tissue (p < 0.0001). Our findings underscore the potential of ORF1p as an early diagnostic marker for cervical neoplasia.

Evaluation of Combined p57KIP2 Immunohistochemistry and Fluorescent in situ Hybridization Analysis for Hydatidiform Moles Compared with Genotyping Diagnosis

Immunostaining with p57KIP2 is a widely used diagnostic technique to differentiate complete hydatidiform moles (CHMs) from partial hydatidiform moles (PHM) and non-molar hydropic abortion. However, distinguishing between PHMs and non-molar hydropic abortions using histopathology alone is often challenging. This study aimed to evaluate the technical validity and additional benefits of using fluorescence in situ hybridization (FISH) in combination with p57KIP2 immunostaining to diagnose molar and non-molar conceptuses. The study involved 80 specimens, which underwent genetic diagnosis using short tandem repeat analysis, including 44 androgenetic CHMs, 20 diandric monogynic PHMs, 14 biparental non-molar hydropic abortions, 1 monoandric digynic triploid abortion, and 1 vaginal specimen of gestational trophoblastic neoplasia. Two pathologists independently diagnosed the cases based on morphology and p57KIP2 immunostaining while the clinical information was masked. FISH analysis was performed using 3 probes (CEP17, CEPX, and CEPY), which revealed that all androgenetic CHM and biparental diploid non-molar hydropic abortion specimens were diploid. Among the 20 diandric monogynic PHM cases examined by analyzing short tandem repeat polymorphisms, 18 were triploid, and the remaining 2 were diploid. These two specimens were possibly androgenetic/biparental mosaics based on FISH analysis, where the three-signal ratios counting 50 cells were clearly within the diploid ranges. Eight of the 20 genetic PHMs and 2 of the 14 genetically confirmed non-molar hydropic abortions that were falsely diagnosed based on morphology and immunohistochemistry by at least 1 pathologist were correctly diagnosed as PHM and non-molar hydropic abortion, respectively, by FISH analysis. However, 1 monoandric digynic villus was classified as triploid by FISH analysis, leading to a false PHM diagnosis. In conclusion, the combination of FISH analysis with p57KIP2 immunostaining helps in diagnosing molar and non-molar conceptuses in numerous cases; nevertheless, exceptional cases should be considered.

Practical Guidance for Measuring and Reporting Surgical Margins in Vulvar Cancer

Surgical resection with free surgical margins is the cornerstone of successful primary treatment of vulvar squamous cell carcinoma (VSCC). In general reexcision is recommended when the minimum peripheral surgical margin (MPSM) is <8 mm microscopically. Pathologists are, therefore, required to report the minimum distance from the tumor to the surgical margin. Currently, there are no guidelines on how to make this measurement, as this is often considered straightforward. However, during the 2018 Annual Meeting of the British Association of Gynaecological Pathologists (BAGP), a discussion on this topic revealed a variety of opinions with regard to reporting and method of measuring margin clearance in VSCC specimens. Given the need for uniformity and the lack of guidance in the literature, we initiated an online survey in order to deliver a consensus-based definition of peripheral surgical margins in VSCC resections. The survey included questions and representative diagrams of peripheral margin measurements. In total, 57 pathologists participated in this survey. On the basis of consensus results, we propose to define MPSM in VSCC as the minimum distance from the peripheral edge of the invasive tumor nests toward the inked peripheral surgical margin reported in millimeters. This MPSM measurement should run through tissue and preferably be measured in a straight line. Along with MPSM, other relevant measurements such as depth of invasion or tumor thickness and distance to deep margins should be reported. This manuscript provides guidance to the practicing pathologist in measuring MPSM in VSCC resection specimens, in order to promote uniformity in measuring and reporting.

Osseous Metaplasia in Low-grade Ovarian Serous Carcinoma With a BRAF Mutation: A Case Report

A 44-yr-old woman presented with lower, painless abdominal discomfort and a vacuolated mass measuring 12 cm on the right-hand side of the pelvis. She subsequently underwent a bilateral salpingo-oophorectomy. An osseous lesion was identified in the left ovary, which was hard in consistency and was associated with a multicystic complex lesion. Microscopic examination of the left ovary showed clusters of serous cells with moderate atypia, surrounded by a desmoplastic stroma with large areas of bone matrix. To the best of our knowledge, this is the first reported case of low-grade serous carcinoma with osseous metaplasia and a BRAF mutation.

The ISGyP Endocervical Adenocarcinoma Project: Master Plan Summary, Acknowledgment of Participants, and Participant Responses to Final Recommendations of the Expert Panels

The International Society of Gynecological Pathologists carried out a multifaceted project with the broad aim of improving the pathological reporting of endocervical adenocarcinoma (EAC). The intentions were to promote and align practices with the WHO 2020 classification, which endorses HPV status-based classification of EAC and the Silva pattern-based assessment of HPV-associated EAC, to promote uniformity in applying the recent FIGO staging revisions on cervical carcinoma, and to provide best practice guidelines on all aspects of EAC pathology reporting. To facilitate the use of the new WHO/IECC classification and the Silva system, two online educational portals were set up with training and test sets of scanned slides; these remain available to society members on the ISGyP educational website. In addition, a large international collaborative individual data collection project is ongoing, aiming to ascertain the prognostic value of EAC categories, and to provide a database with the potential to address unanswered questions. A single on-site meeting was held on February 29, 2020 in Los Angeles, in advance of the USCAP Annual Meeting; all other correspondence was by email and through electronic surveys. Project participants were invited to vote and comment on the recommendations contained within the practice guideline articles. The project received an enthusiastic response from pathologists across the world. This report includes an overview and summary of all aspects of the project, a list of participants and the results of polling on practice recommendations.

Survey Results on Pathologic Aspects of Endocervical Adenocarcinoma by the International Society of Gynecological Pathologists

The International Society of Gynecological Pathologists (ISGyP) undertook a project to provide evidence-based recommendations for pathologic reporting of all aspects of endocervical adenocarcinoma. The first step in the process was the design of an extensive survey to collect baseline information on existing practices regarding grossing, processing, diagnosing, and reporting of endocervical adenocarcinoma among the members of the society. The web-based survey of 98 questions was emailed to all members of ISGyP and there were 175 respondents (38.5% of ISGyP members). The responses, as expected, revealed areas of uniformity but also areas of substantial variation. The results of the survey are presented herein and assisted in developing the recommendations presented in the other reviews in this issue.

Tumor Typing of Endocervical Adenocarcinoma: Contemporary Review and Recommendations From the International Society of Gynecological Pathologists

The incidence of endocervical adenocarcinoma, the second most common cervical cancer in the world, has been on the rise. While most cervical cancers are squamous cell carcinomas and associated with high-risk oncogenic human papillomavirus (HPV), approximately 15% of endocervical adenocarcinomas, which now represent about one quarter of all cervical cancers, are HPV-independent. In this review, we will focus on the shortcomings of historical histologic classification systems of female genital tract tumors as they pertain to endocervical adenocarcinomas, and we will highlight the advantages of the new International Endocervical Adenocarcinoma Criteria and Classification system, which forms the basis for the WHO 2020 classification. We will cover the various histologic types, subtypes, and variants of endocervical adenocarcinoma with regard to morphology, immunophenotype, molecular genetics, HPV status and differential diagnosis, and we will provide International Society of Gynecological Pathologists recommendations for diagnosing these tumors.

The Silva Pattern-based Classification for HPV-associated Invasive Endocervical Adenocarcinoma and the Distinction Between In Situ and Invasive Adenocarcinoma: Relevant Issues and Recommendations From the International Society of Gynecological Pathologists

The Silva pattern-based classification for human papilloma virus–associated invasive adenocarcinoma has emerged as a reliable system to predict risk of lymph node metastasis and recurrences. Although not a part of any staging system yet, it has been incorporated in synoptic reports as established by the College of American Pathologists (CAP) and the International Collaboration on Cancer Reporting (ICCR). Moreover, the current National Comprehensive Cancer Network (NCCN) guidelines include this classification as an “emergent concept.” In order to facilitate the understating and application of this new classification by all pathologists, the ISGyP Endocervical Adenocarcinoma Project Working Group presents herein all the current evidence on the Silva classification and aims to provide recommendations for its implementation in practice, including interpretation, reporting, and application to biopsy and resection specimens. In addition, this article addresses the distinction of human papilloma virus–associated adenocarcinoma in situ and gastric type adenocarcinoma in situ from their invasive counterparts.

Tumor Staging of Endocervical Adenocarcinoma: Recommendations From the International Society of Gynecological Pathologists

The International Federation of Gynecology and Obstetrics (FIGO) updated its staging system for cervical cancer in 2018 with changes that affect size criteria for early stage disease, as well as including pathology and radiology in addition to clinical assessment to be used in staging. Lymph node involvement was also included in the staging system. In early stage disease, pathologic findings are crucial in determining stage, which in turn determine treatment and prognosis for the patient. Therefore, it is imperative that there are unified and consistent methods and recommendations for assessing and reporting pathologic parameters for accurate staging. We describe the changes in the revised FIGO staging scheme and discuss controversial issues in cervical cancer staging from a pathologic perspective. We also provide practical recommendations regarding these parameters based on literature review and/or expert opinion/consensus.

The Role of Predictive Biomarkers in Endocervical Adenocarcinoma: Recommendations From the International Society of Gynecological Pathologists

To review the scientific evidence related to predictive biomarkers in cervical adenocarcinoma (ADC). The authors reviewed the literature regarding predictive biomarkers in cervical ADC. There were several limitations: (1) there is an overlap between predictive and prognostic biomarkers, as the vast majority of patients are treated with anticancer strategies; (2) in many studies and clinical trials, cervical ADC patients are included in a large series of patients predominantly composed of cervical squamous cell carcinomas; and (3) in most of the studies, and clinical trials, there is no distinction between human papillomavirus (HPV)-associated and HPV-independent cervical ADCs, or between various histologic subtypes. Results obtained from a small group of studies confirm that cervical ADCs exhibit distinct molecular features as compared with squamous carcinomas, and that there are different molecular features between different types of cervical ADCs. Promising areas of interest include ERBB2 (HER2) mutations and PD-L1 expression as predictive biomarkers for anti-HER2 treatment and immunotherapy, respectively. To date, no definitive data can be obtained from the literature regarding predictive biomarkers for cervical ADC. Clinical trials specifically designed for endocervical ADC patients are required to elucidate the predictive value of HER2 mutations and PD-L1 expression. The distinction between HPV-associated and HPV-independent cervical ADCs as well as early involvement of pathologists in the design of future clinical trials are needed to identify new predictive biomarkers in cervical ADC.

Endocervical Adenocarcinoma, Gross Examination, and Processing, Including Intraoperative Evaluation: Recommendations From the International Society of Gynecological Pathologists

The International Society of Gynecological Pathologists (ISGyP) Endocervical Adenocarcinoma Project aims to provide evidence-based guidance for the pathologic evaluation, classification, and reporting of endocervical adenocarcinoma. This review presents the recommendations pertaining to gross evaluation and intraoperative consultation of specimens obtained from patients in the setting of cervical cancer. The recommendations are the product of review of published peer-reviewed evidence, international guidelines and institutional grossing manuals, as well as deliberation within this working group. The discussion presented herein details the approach to the different specimen types encountered in practice: loop electrosurgical excision procedure, cone, trachelectomy, radical hysterectomy, pelvic exenteration, and lymphadenectomy specimens. Guidelines for intraoperative evaluation of trachelectomy and sentinel lymph node specimens are also addressed. Correlation with ISGyP recommendations on cancer staging, which appear as a separate review in this issue, is also included when appropriate. While conceived in the framework of endocervical adenocarcinoma, most of the discussion and recommendations can also be applied to other cervical malignancies.

Online Training and Self-assessment in the Histopathologic Classification of Endocervical Adenocarcinoma and Diagnosis of Pattern of Invasion: Evaluation of Participant Performance

Histopathologic classification of endocervical adenocarcinomas (EAC) has recently changed, with the new system based on human papillomavirus (HPV)-related morphologic features being incorporated into the 5th edition of the WHO Blue Book (Classification of Tumours of the Female Genital Tract). There has also been the introduction of a pattern-based classification system to assess invasion in HPV-associated (HPVA) endocervical adenocarcinomas that stratifies tumors into 3 groups with different prognoses. To facilitate the introduction of these changes into routine clinical practice, websites with training sets and test sets of scanned whole slide images were designed to improve diagnostic performance in histotype classification of endocervical adenocarcinoma based on the International Endocervical Adenocarcinoma Criteria and Classification (IECC) and assessment of Silva pattern of invasion in HPVA endocervical adenocarcinomas. We report on the diagnostic results of those who have participated thus far in these educational websites. Our goal was to identify areas where diagnostic performance was suboptimal and future educational efforts could be directed. There was very good ability to distinguish HPVA from HPV-independent adenocarcinomas within the WHO/IECC classification, with some challenges in the diagnosis of HPV-independent subtypes, especially mesonephric carcinoma. Diagnosis of HPVA subtypes was not consistent. For the Silva classification, the main challenge was related to distinction between pattern A and pattern B, with a tendency for participants to overdiagnose pattern B invasion. These observations can serve as the basis for more targeted efforts to improve diagnostic performance.

The ISGyP Endocervical Adenocarcinoma Project

Atypical Endometriosis: Comprehensive Characterization of Clinicopathologic, Immunohistochemical, and Molecular Features

Atypical endometriosis (A-EMS), defined by cytologic atypia and/or crowded glands resembling endometrial intraepithelial neoplasia, remains poorly understood. We aimed to refine the morphologic, immunohistochemical, and molecular features of A-EMS in an institutional series. Cases were identified through a structured search and reviewed by 2 pathologists. Immunohistochemistry and comprehensive sequencing using a panel 447-gene coverage were performed in suitable cases. A-EMS with synchronous and/or subsequent EMS-related neoplasia were compared with those without. Of 4598 EMS cases over an 11-yr period, 36 A-EMS were identified. The mean age at presentation was 46 (range 26–68) yr. Locations included the ovary (24, 66%), tubo-ovary (6, 17%), fallopian tube (3, 8%), and peritoneum (3, 8%). The mean size was 6.5 (range 0.5–40) mm. Cytologic atypia was mild in 4 (11%), moderate in 21 (58%), and severe in 11 (31%). Most lesions were partially or completely flat (28, 78%); of these, 66% showed hobnail nuclei. Crowded/cribriform and micropapillary/papillary patterns were seen in 11 (31%) and 16 (44%) A-EMS, respectively. Immunohistochemistry, performed in 33 A-EMS, showed wildtype p53 (100%) retained PMS2/MSH6 (100%), and positive estrogen receptor (97%, mean 65% cells), progesterone receptor (76%, mean 30% cells), and Napsin A (39%). Ki67 labelling was <1% to 10% (median 5%). Nine (25%) patients presented with concurrent or subsequent ipsilateral endometrioid, seromucinous, or clear cell neoplasia (4 borderline tumors and 4 carcinomas). The only A-EMS feature statistically more frequent in this subset was crowded/glands (6/9 vs. 2/27 A-EMS without, P=0.001 Fisher exact test). Sequencing showed pathogenic variants in 5 of 6 cases analyzed, involving ATM, BRCA2, KRAS, AKT, CTNNB1, PTEN, and ARID1A among other genes. In 2 cases, synchronous neoplasia showed an accumulation of additional variants. A-EMS is characterized by cytologic atypia and crowded architecture but low proliferation index, positive estrogen receptor, and normal p53 and MMR, which can be helpful in the distinction from malignancy. The prevalence of synchronous/subsequent tubo-ovarian neoplasia in our series was 25%, significantly higher than the reported 1% in conventional EMS. Moreover, A-EMS harbors genomic alterations seen in EMS-related tumors and shares pathogenic variants with synchronous ipsilateral neoplasia. Therefore, it is important to report A-EMS as currently defined and describe its architectural features, especially gland crowding as this appears to increase the risk of EMS-related epithelial neoplasia. Napsin-A is often positive in A-EMS and should be interpreted with caution.

Postchemotherapy Endometrioid to Gastrointestinal Histotype Shift in Recurrent Endometrial Carcinoma

Herein, we report a case of low-grade endometrial endometrioid carcinoma recurred on the vaginal stump, which showed a complete histotype shift toward a gastrointestinal-type carcinoma after chemotherapy. The recurrent tumor increased in volume during chemotherapy. Postchemotherapy histologic examination showed a pure mucinous signet-ring cell pattern with positivity for cytokeratin 20 and CDX2, focal SATB2 expression and negativity for cytokeratin 7 and estrogen and progesterone receptors. Such features led to consider a diagnosis of metastasis from a primary carcinoma of the gastrointestinal tract. The accurate exclusion of any primary lesions of gastrointestinal and of other sites allowed identifying the tumor as the recurrent endometrial carcinoma. Our case highlights that chemotherapy may induce a histotype shift from endometrioid carcinoma to gastrointestinal-type carcinoma; such occurrence might be a mechanism of resistance and might provide new insights on the sensitiveness of different histotypes to systemic therapies. Considering the possibility of a shift from endometrioid to gastrointestinal-type carcinoma may be useful for a correct diagnosis and an appropriate patient management.

Endometrioma and Mature Cystic Teratoma as Collision Tumors of the Ovary: A Case Series and Literature Review

The simultaneous presence of distinct histologic types of ovarian cysts in a single patient, known as “collision tumors,” presents a clinical challenge. In this study, we report 19 new cases of ovarian collision tumors involving both endometriomas and mature cystic teratomas (MCTs), and we review their characteristics alongside 30 previously reported cases. Among the total of 49 patients, the mean age was 32.28±8.07 yr, with 66.67% being nulliparous. The most common clinical symptom was abdominal pain (55.10%), while 12.24% were diagnosed incidentally. Primary infertility was identified in 14.28% of patients. Of the 44 cases with available surgical data, 32 underwent cystectomy and 12 underwent oophorectomy. In the 19 newly reported cases, 10 patients desired fertility preservation, yet only one achieved spontaneous pregnancy after surgery. Although both endometriomas and MCTs are benign ovarian lesions, their coexistence is rare. Tissue diagnosis is essential to exclude malignancy and guide follow-up, but preserving ovarian reserve is equally critical. Recognizing the presence of collision tumors can help physicians utilize radiologic methods more effectively and adopt a more proactive approach, safeguarding the future fertility and quality of life of these patients.

SMARCA4/BRG1-deficient Uterine Neoplasm With Hybrid Adenosarcoma and Carcinoma Features: Expanding the Molecular-morphologic Spectrum of SMARCA4-driven Gynecologic Malignancies

SMARCA4 gene encodes BRG1, a member of the SWItch/sucrose non-fermentable protein family involved in epigenetic transcriptional regulation of important cellular processes. In the uterine corpus, SMARCA4/BRG1 deficiency is associated with a novel class of undifferentiated uterine sarcomas, characterized by younger age onset, rhabdoid histology, focal phyllodiform architecture, high-risk pathologic findings, and dismal prognosis. Herein, we report a case of a 34-year-old Asian woman with a SMARCA4/BRG1-deficient uterine tumor fulfilling the clinicopathologic features of an undifferentiated uterine sarcoma. However, the tumor exhibited several unique features that have not been previously emphasized, including (1) conspicuous phyllodiform architecture recapitulating conventional adenosarcoma, (2) rhabdoid tumor cells forming cords and keratin-positive cohesive epithelial islands, and (3) cooccurrence with a spatially distinct and discrete endometrial complex atypical hyperplasia from the rest of the proliferation. By immunohistochemistry, the tumor cells were diffusely positive for synaptophysin, whereas BRG1 was lost. Pertinent molecular findings included frameshift mutations in the SMARCA4 gene, mutations in histone modification and chromatin remodeling genes, including KMT2C, ARID1B, KAT6A, and NCOR1, and mutations in Wnt signaling involving APC and CTNNB1. Copy number gain in MDM2 and CDK4 were also identified. The tumor mutation burden was intermediate (6.8/MB) and it was microsatellite stable. On balance, our case exhibited morphologic and molecular features that overlap with (1) an undifferentiated uterine sarcoma, (2) an adenosarcoma with sarcomatous overgrowth, and (3) a mixed adenosarcoma and undifferentiated endometrial carcinoma. These hybrid features further expand the molecular-morphologic spectrum of SMARCA4/BRG1-deficient uterine neoplasms.

Clinicopathologic Characteristics of a Single-institution Cohort of Ovarian Adult Granulosa Cell Tumors, With Biomarker and Therapeutic Implications Utilizing the Detection of Androgen, Estrogen, and Progesterone Hormone Receptor Expression by Immunohistochemistry

Adult granulosa cell tumors (AGCTs) are rare ovarian tumors with generally good prognosis after surgical resection; however, they do have recurrence potential. Therapeutic and management options for recurrences are currently limited, and the need for expanded adjuvant therapies is increasingly recognized. Anti-hormonal therapy is being explored as an option, which relies on the detection and assessment of hormone receptor expression (androgen, estrogen, and progesterone receptors) as a biomarker and therapeutic target. Our study identifies several clinicopathologic characteristics with significant associations for recurrence of AGCT, which were younger age, higher stage, and larger tumor size. Our study also demonstrates that androgen receptor (AR) expression may be utilized as a potential biomarker for hormonal therapy and that detection of AR expression in AGCT by immunohistochemistry (IHC) varies depending on the antibody clone used for testing. AR was detected in 95% of samples tested with antibodies derived from clone AR27. This detection rate is much higher than previously reported.

Moderately-differentiated Ovarian Sertoli-Leydig Cell Tumor With a Concurrent Serous Borderline Tumor in a 16-year-old Girl

Sertoli-Leydig cell tumors (SLCT) are rare tumors of the ovary with a peak incidence in the second to third decade of life. Serous borderline tumors (SBT) are epithelial ovarian neoplasms which occur at a median age of 50 years. A co-occurrence of SLCT and SBT has not yet been reported. Here, we describe a case of a 16-year-old girl who presented with irregular menses, virilization, and an abdominopelvic mass. The mass was surgically removed and an intraoperative consultation revealed an 18.5 cm solid and cystic ovarian mass with the presence of co-existing SLCT and SBT. The diagnosis was confirmed on permanent sections after extensive sampling and immunohistochemical stains. The SLCT showed positive staining for calretinin, inhibin, CD99, and androgen receptor. MART-1 immunostain highlighted the Leydig cells. The SBT showed classic features including hierarchically branching papillae lined by stratified serous epithelium. This pediatric case is the first reported case of a Sertoli-Leydig cell tumor arising in association with a serous borderline tumor.

Migrated Bulking Material (Solesta) Presenting as a Vaginal “Cyst”: Histopathologic and Chemical Analytical Features

Performing injections with a bulking agent consisting of nonanimal stabilized hyaluronic acid and dextranomer is a well-tolerated and efficacious treatment for mild to moderate fecal incontinence. Here, we discuss a case of a patient with a history of a bulking procedure for fecal incontinence who presented to the obstetrics/gynecology clinic for evaluation of a new vaginal “cyst,” which was excised. Histopathologic examination revealed migrated bulking agent within the excised specimen.

Ovarian Mucinous Borderline Tumor With Intraepithelial Carcinoma

DICER1-Altered Extraovarian Moderately Differentiated Sertoli-Leydig Cell Tumor: Report of a Rare Case

We report an unusual case of a pelvic extraovarian moderately differentiated Sertoli-Leydig cell tumor arising in a 4-yr-old female. The tumor contained a DICER1 pathogenic variant which was absent in the germline ruling out DICER1 syndrome. In reporting this case, we discuss the differential diagnosis and possible histogenesis and review reported cases of extraovarian Sertoli-Leydig cell tumor.

Ovarian Malignant Mixed Germ Cell Tumor With Prominent Embryoid Bodies (Polyembryoma Background): A Case Report and Literature Review

Ovarian malignant mixed germ cell tumors are rare tumors occurring in young women. The presence of prominent embryoid bodies in these tumors is extremely uncommon. Herein, we report such a case, with a histomorphologic description and immunohistochemical and fluorescence in situ hybridization analyses.

HMGA2 Is a Useful Marker of Vulvovaginal Aggressive Angiomyxoma But May Be Positive in Other Mesenchymal Lesions at This Site

Aggressive angiomyxoma (AA) is a rare mesenchymal neoplasm occurring almost exclusively in the vulvovaginal region and which has a wide differential diagnosis. It has previously been suggested that the nuclear transcription factor HMGA2 is a useful marker of AA, although the number of studies is limited. We investigated HMGA2 immunoreactivity in a large series (n=284) of vulvovaginal mesenchymal lesions. HMGA2 nuclear staining was classified as diffuse (≥50%), focal (<50%), or negative. Of 38 cases of AA, 26 (68%) were positive; 77% (n=20) of these exhibited diffuse staining. Of the 41 smooth muscle tumors, 18 (44%) were positive with 16 (89%) exhibiting diffuse staining. 80 fibroepithelial stromal polyps were included and 15 (19%) were positive (8 diffuse; 7 focal). Most of the fibroepithelial stromal polyps that exhibited diffuse HMGA2 immunoreactivity were large and edematous. Occasional cases of a variety of other lesions were positive, including 1 of 30 superficial myofibroblastomas and 1 of 16 angiomyofibroblastomas. Cellular angiofibromas (n=12) and superficial angiomyxomas (n=6) were always negative. Our results confirm that HMGA2 is a useful marker of AA but a significant minority of cases are negative. The marker also lacks specificity, since a high percentage of smooth muscle tumors are positive, although these typically do not bear a close morphologic resemblance to AA. A novel observation in our study is positive staining of some fibroepithelial stromal polyps, particularly when large and edematous; these are particularly likely to be confused morphologically with AA and positive staining with HMGA2 represents a significant diagnostic pitfall.

Collision Tumor of the Ovary Involving Sertoli-Leydig Cell Tumor and High-Grade Serous Carcinoma—Report of the First Case

We report a collision tumor in the ovary of a 60-yr-old woman composed of high-grade serous carcinoma and Sertoli-Leydig cell tumor. Collision tumors in the ovary are rare and to the best of our knowledge, combination of ovarian high-grade serous carcinoma and Sertoli-Leydig cell tumor has not been described before.

Mutational Profile in Vulvar, Vaginal, and Urethral Melanomas: Review of 37 Cases With Focus on Primary Tumor Site

Melanomas of female genital tract are rare tumors with poor prognosis. While BRAF-V600E is the most common pathogenic mutation seen in cutaneous sun-exposed melanomas, mucosal and anogenital melanomas usually lack BRAF mutations and instead they harbor KIT alterations. The American Joint Committee on Cancer staging guideline (AJCC eighth edition) recommends using cutaneous melanoma guidelines for vulvar melanoma staging and does not provide any recommendations for vaginal melanoma staging. The aim of this study is to investigate the mutational status of invasive melanomas arising from different anatomic sites in lower female genital tract (vulvar hair-bearing skin, glabrous skin, vagina and urethra) in a group of 37 patients. Tumors were analyzed using a DNA targeted next-generation sequencing panel covering the 21 most common genes and mutation hotspots in melanomas. The most common genetic alterations in invasive melanomas of lower female genital tract are KIT (32%), TP53 (22%), and NF1 (19%). Overall 66% (21/32) of cases showed a pathogenic alteration in at least one of the MAPK pathway genes. No statistical significance seen between different primary tumor sites and the frequency of the oncogenic mutations, nor were any significant differences found by mutation status. Only one case of urethral melanoma showed a BRAF non-V600E mutation (D594G). Our results suggest a similar molecular pathogenesis and overall survival in melanomas arising from lower female genital tract, irrespective of their exact location in the urogenital area. Future classifications of melanoma should consider grouping vulvar melanomas with mucosal rather than cutaneous melanomas.

BAP1 and Claudin-4, But Not MTAP, Reliably Distinguish Borderline and Low-grade Serous Ovarian Tumors From Peritoneal Mesothelioma

Peritoneal mesothelioma (PM) and serous neoplasms can be difficult to differentiate, particularly in small biopsies. BRCA1-associated protein 1 (BAP1) is expressed in benign tissues, but over 50% of PMs demonstrate complete loss of nuclear expression. Claudin-4, a tight junction protein, is expressed in most epithelial tumors but not in mesotheliomas. Methylthioadenosine phosphorylase (MTAP) is frequently co-deleted with cyclin-dependent kinase inhibitor 2a in mesotheliomas. These markers have proven useful in separating mesothelioma from its mimics, particularly when tumors are pleural based. In the peritoneum, BAP1 loss has been rarely reported in high-grade serous carcinomas, but overall, these markers have been minimally evaluated in ovarian serous borderline tumors and low-grade serous carcinomas. Thus, we assessed the utility of BAP1, claudin-4, and MTAP in the differential diagnosis of PM and low-grade serous neoplasms. Eighteen PM (16 epithelioid, 1 biphasic, and 1 sarcomatous), 24 low-grade serous carcinomas, and 25 serous borderline tumors were stained for BAP1, claudin-4, and MTAP. Loss of BAP1 nuclear expression was observed in 12 (67%) PM (11 epithelioid, 1 biphasic) but was retained in all serous tumors. Claudin-4 was positive in all serous tumors and negative in all PM. Complete loss of cytoplasmic MTAP was noted in 3 (17%) PMs and 1 (4%) serous borderline tumor, while all low-grade serous carcinomas showed retained expression. BAP1 loss reliably distinguishes PM from serous tumors, although it lacks sensitivity. Claudin-4 is a reliable marker to exclude PM. MTAP loss may occur in both PM and serous tumors, and thus is not useful in distinguishing these entities.

Anastomosing Hemangioma of the Ovary With Leydig Cell Hyperplasia: A Clinicopathologic Study of 12 Cases

Anastomosing hemangioma is a recently described vascular neoplasm, initially identified in the male genitourinary tract. Since its first description, it has been reported at multiple anatomic sites, including rare cases in the female genital tract, most in the ovary. Herein we report the largest series to date of 12 ovarian anastomosing hemangiomas identified at our institution over a 15-yr period. The patients’ age at the time of resection ranged from 50 to 76 yr (median: 62 yr), 3 patients presented with symptomatic pelvic masses, 3 tumors were identified by imaging studies, and the remaining 6 were incidentally discovered in ovaries removed for other indications. All tumors were unilateral, occurred at the ovarian hilum, and contained a vaguely lobulated architecture with sinusoidal-like vessels lined by hobnail endothelial cells with minimal to no cytologic atypia. A rim of luteinized/Leydig cells with abundant, eosinophilic cytoplasm and round, centrally placed nuclei surrounding the hemangioma was present in 9/12 tumors. Reinke crystals were observed in 3 of these 9 tumors. The volume of luteinized cells relative to the vascular proliferation ranged from 2% to 30%. All tumors with luteinized/Leydig cells also displayed numerous small eosinophilic, globular intracytoplasmic inclusions within the endothelial cells. The 3 tumors without luteinized/Leydig cells were exclusively intravascular lesions. Despite the frequent presence of luteinization/Leydig cells none of the patients experienced hormonal manifestations. Awareness of this rare benign ovarian entity is important, as its association with luteinized cells/Leydig cell hyperplasia (often exuberant) may be misinterpreted as a steroid cell tumor, Leydig-cell tumor, or as a mixed stromal-vascular tumor.

Paraganglioma of the Vagina Associated With Germline SDHB Mutation: Report of a Case With Review of the Literature

Paragangliomas are rare neuroendocrine neoplasms in the vagina, and their molecular pathogenesis has not been documented. We report a case of vaginal paraganglioma in a 15-yr-old adolescent girl who presented with irregular heavy menses and anemic symptoms. Examination under anesthesia revealed a polypoid mass of 3 cm size in the left anterior vaginal wall, which was resected piecemeal. Histology showed a circumscribed nodular tumor with typical nested morphology of paraganglioma and no significant nuclear atypia. Immunohistochemically the tumor cells were diffusely positive for synaptophysin and chromogranin while being negative for cytokeratin, accompanied by S100-positive sustentacular cells. SDHB immunohistochemistry demonstrated the absence of cytoplasmic staining in the tumor cells with preserved staining in sustentacular cells, raising the possibility of a germline mutation in the genes encoding subunits of succinate dehydrogenase. Sanger sequencing for all the exons and exon-flanking intronic regions of theSDHBgene revealed no mutation, but further investigation with multiplex ligation-dependent probe amplification identified a heterozygous deletion of exon 1 of theSDHBgene in the patient and her mother, confirming the diagnosis ofSDHB-related hereditary paraganglioma-pheochromocytoma syndrome. The patient had no evidence of disease upon imaging surveillance and follow-up for 56 mo. A review of the published cases of vaginal paraganglioma seems to suggest a relatively young age of presentation, commonly encountered as incidental findings in asymptomatic patients or presenting with abnormal vaginal bleeding. The association between vaginal paraganglioma and germlineSDHBmutation has not been reported. We believe this case illustrates the clinical significance of SDHB immunohistochemistry and genetic testing for this rare vaginal neoplasm.

Ovarian Combined Serous Borderline Tumor/Low-grade Serous Carcinoma and Mesonephric-like Lesion: Report of 2 Cases With New Observations

Ovarian combined serous borderline tumor/low-grade serous carcinomas (SBT/LGSC) and mesonephric-like adenocarcinomas (MLA) have been previously reported and the presence of identical oncogenic somatic mutations in both components supports the concept that at least some of MLAs arise from a Müllerian origin. We report 2 cases of ovarian combined SBT/LGSC and mesonephric-like lesion. Case 1 was a 70-yr-old woman presented with a liver lesion and omental carcinomatosis. Histologic examination revealed biphasic tumors in bilateral ovaries consisting of conventional SBT and invasive MLA with extraovarian spread. The right ovary also had a component of cribriform variant of SBT/noninvasive LGSC. The SBT/LGSC component was diffusely positive for Pax8, WT-1, and ER, focally positive for PR, and negative for GATA3, while the MLA component was diffusely positive for GATA3 but negative for WT-1, ER, and PR. Molecular analysis revealed a KRAS G12V mutation in both the SBT/LGSC and MLA components, indicating their clonal origin. Case 2 was a 58-yr-old woman who presented with conventional type SBT in both ovaries. In addition, the left ovarian tumor demonstrated a few areas (each <5 mm) of mesonephric-like differentiation/hyperplasia in close proximity to the serous-type epithelium, with an immunophenotype of focal GATA3 expression, luminal pattern of CD10 staining and negative WT-1, ER, and PR staining. This phenomenon has been reported in endometrioid borderline tumor but not in any serous type lesions. The findings in case 1 provide further evidence to demonstrate the clonal relationship between these morphologically and immunophenotypically distinct components. It also supports the theory that, unlike cervical mesonephric carcinomas originating from mesonephric remnants, MLAs are derived from a Müllerian-type lesion with differentiation into mesonephric lineage. The presence of a hyperplastic mesonephric-like lesion/differentiation in case 2 indicates that a precursor lesion in the same lineage with the potential to develop into MLA exists in the ovary.

BAP1 Tumor Predisposition Syndrome Presenting as a Recurrent Ovarian Sex Cord-Stromal Tumor

The BRCA1-associated protein 1 (BAP1) gene encodes a tumor suppressor that functions as a ubiquitin hydrolase involved in DNA damage repair. BAP1 germline mutations are associated with increased risk of multiple solid malignancies, including mesothelioma, uveal melanoma, renal cell carcinoma, and high-grade rhabdoid meningiomas. Here, we describe the case of a 52-yr-old woman who experienced multiple abdominal recurrences of an ovarian sex cord-stromal tumor that was originally diagnosed at age 25 and who was found to have a germline mutation in BAP1 and a family history consistent with BAP1 tumor predisposition syndrome. Recurrence of the sex cord-stromal tumor demonstrated loss of BAP1 expression by immunohistochemistry. Although ovarian sex cord-stromal tumors have been described in mouse models of BAP1 tumor predisposition syndrome, this relationship has not been previously described in humans and warrants further investigation. The case presentation, tumor morphology, and immunohistochemical findings have overlapping characteristics with peritoneal mesotheliomas, and this case represents a potential pitfall for surgical pathologists.

Uterine Tumor Resembling Ovarian Sex Cord Tumor With Aggressive Histologic Features Harboring a GREB1-NCOA2 Fusion: Case Report With a Brief Review

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare mesenchymal neoplasm, of uncertain lineage, that shows predominantly sex cord-like differentiation with a broad range of histologic appearances and polyphenotypic immunohistochemical features. Although generally having a favorable prognosis, a subset can recur/metastasize. Most recently, several studies of UTROSCT have described novel fusion genes involving ESR1 and GREB1 as the 5 partner, and NCOA1-3 as the 3 partner. Genotype and phenotype correlation has suggested that GREB1-rearranged tumors may have a higher tendency to behave aggressively. Herein, we report a UTROSCT with aggressive histologic features harboring a GREB1-NCOA2 fusion. A 51-yr-old woman presented with menometrorrhagia and progressive dysmenorrhea and was found to have a submucous uterine lesion by ultrasonography. Gross examination of the hysterectomy specimen showed an 8.5-cm, polypoid, soft, intracavitary mass. Histologic examination revealed a deeply invasive neoplasm composed of uniform round to plump spindle cells, arranged predominantly in diffuse sheets and fascicles and focally in anastomosing cords patterns. Groups of rhabdoid tumor cells were occasionally noted. Worrisome features, including increased mitotic figures (up to 3/10 high power fields), geographic necrosis, and lymphovascular invasion, were evident. Immunohistochemical analysis showed variable positivity for epithelial, smooth muscle, neuroendocrine, and sex cord markers, as well as hormone receptors. RNA sequencing revealed an in-frame fusion between exon 3 of GREB1 and exon 14 of NCOA2. Fluorescence in situ hybridization analyses confirmed rearrangements of both the GREB1 and NCOA2 loci. Our case lends further supports that GREB1-rearranged UTROSCTs frequently exhibit aggressive histological features with inconspicuous sex cord-like differentiation.

Bronchus-like Structures in Ovarian Teratomas: Report of a Series of a Previously Unreported Phenomenon With Potential For Misdiagnosis

We report 10 cases of a previously undescribed lesion within ovarian teratomas which we designate bronchus-like structures. The lesions occurred in patients aged 16 to 56 yr (mean: 36) and involved the left ovary (n=5) or right ovary (n=5). Nine cases were mature teratomas (dermoid cysts/mature cystic teratomas or mature solid teratomas), 1 with somatic malignant transformation, and 1 was an immature teratoma. The bronchus-like structures ranged in size from 2.5 to 10 mm and were unifocal (7 cases) or multifocal (3 cases). The morphology was relatively constant in all cases and characterised by a well-formed bronchus surrounded by glandular structures, some of which were dilated, separated by stroma containing a variable amount of smooth muscle. In all but 1 case, a proportion of the glands contained abundant foamy cytoplasm. There was little or no nuclear atypia or mitotic activity. At low-power, the glands often had a somewhat “infiltrative” appearance and one case was originally diagnosed as a “pulmonary-type” adenocarcinoma arising in a dermoid cyst. In all cases, there was diffuse staining of the bronchus and glands with TTF1 and Napsin A, confirming the cell lineage. Follow-up in 4 cases (18–130 mo; median: 64 mo) showed no evidence of recurrence; 1 patient died from an unrelated malignancy. In reporting this apparently rare but possibly underrecognized benign lesion arising within ovarian teratomas, we discuss the differential diagnosis and stress that pathologists should be aware of this phenomenon in order to avoid an erroneous diagnosis of malignancy.

Prognostic and Theranostic Biomarkers in Ovarian Clear Cell Carcinoma

In this study, we aimed to test whether prognostic biomarkers can achieve a clinically relevant stratification of patients with stage I ovarian clear cell carcinoma (OCCC) and to survey the expression of 10 selected actionable targets (theranostic biomarkers) in stage II to IV cases. From the population-based Alberta Ovarian Tumor Type study, 160 samples of OCCC were evaluated by immunohistochemistry and/or silver-enhanced in situ hybridization for the status of 5 prognostic (p53, p16, IGF2BP3, CCNE1, FOLR1) and 10 theranostic biomarkers (ALK, BRAF V600E, ERBB2, ER, MET, MMR, PR, ROS1, NTRK1-3, VEGFR2). Kaplan-Meier survival analyses were performed. Cases with abnormal p53 or combined p16/IFG2BP3 abnormal expression identified a small subset of patients (6/54 cases) with stage I OCCC with an aggressive course (5-yr ovarian cancer-specific survival of 33.3%, compared with 91.5% in the other stage I cases). Among theranostic targets, ERBB2 amplification was present in 11/158 (7%) of OCCC, while MET was ubiquitously expressed in OCCC similar to a variety of normal control tissues. ER/PR showed a low prevalence of expression. No abnormal expression was detected for any of the other targets. We propose a combination of 3 biomarkers (p53, p16, IGF2BP3) to predict prognosis and the potential need for adjuvant therapy for patients with stage I OCCC. This finding requires replication in larger cohorts. In addition, OCCC could be tested for ERBB2 amplification for inclusion in gynecological basket trials targeting this alteration.

Müllerian Mucinous Cystadenomas of the Ovary: A Report of 25 Cases of an Unheralded Benign Ovarian Neoplasm Often Associated With Endometriosis and a Brief Consideration of Neoplasms Arising From the Latter

A subset of ovarian mucinous tumors demonstrates müllerian-type epithelium, with such lesions variably designated “endocervical-like” and seromucinous since their popularization based on a report of borderline examples in 1989. While müllerian mucinous borderline tumors and carcinomas have been highlighted in the literature, there has been minimal attention given to benign müllerian mucinous tumors, particularly müllerian mucinous cystadenomas. Given the paucity of literature describing the features of müllerian mucinous cystadenomas/cystadenofibromas, diagnostic difficulties may arise when papillary features are present and in cases that show a subtle transition from endometriosis. We thus reviewed 25 cases of müllerian mucinous cystadenoma/cystadenofibroma to highlight the notable characteristics of this entity, including gross, cytologic, and architectural features that aid in the distinction from müllerian mucinous borderline tumors as well as, rarely, metastatic tumors. The patients ranged in age from 26 to 85 yr old. Bilateral ovarian involvement was frequent (40%). The ovaries ranged from 2.3 to 26 cm in greatest dimension. Most were multicystic (18 cases) and contained tenacious mucoid material (14 cases). All cases demonstrated predominantly columnar mucinous epithelium with abundant pale-pink cytoplasm. A minor component of ciliated and endometrioid epithelium was seen in 15 and 2 cases, respectively. Broad papillary formations were frequently encountered (9 cases) as was epithelial papillary tufting comprising <10% of the tumor (6 cases). Endometriosis was present in 9 cases, with a transition from endometriosis to mucinous epithelium noted in 8 cases. This series highlights the morphologic features of a relatively uncommon, benign, endometriosis-associated ovarian tumor that may be confused with a müllerian mucinous borderline tumor or bland metastatic mucinous tumors. It also provides an argument for the terminology “müllerian mucinous cystadenoma” or “cystadenofibroma” rather than “seromucinous cystadenoma” due to the frequent association with endometriosis as well as the dominant mucinous epithelium.

Ovarian Clear Cell Tumors Associated With Seromucinous Borderline Tumor: A Case Series

Ovarian seromucinous borderline tumors (SMBT) and clear cell tumors are both closely associated with endometriosis and share, in a proportion of cases, a molecular pathway involving ARID1A mutations, but they have been rarely described in association. We report a case series of 4 clear cell tumors (3 carcinomas, 1 borderline adenofibroma) coexisting in the same ovary with SMBT. In all cases, the SMBT was the predominant component and we highlight that adequate sampling of these tumors is important to detect small clear cell carcinomas, thus potentially altering the treatment and prognosis.

The Relationship Between Melatonin 1-2 Receptor Expression in Patients With Epithelial Ovarian Cancer and Survival

Melatonin has antiproliferative, antiangiogenic, apoptotic, and immunomodulatory properties in ovarian cancer. Considering those, we evaluated the relationship between melatonin 1 (MT1) and melatonin 2 receptor (MT2) expression in tumor tissues of patients with epithelial ovarian cancer, disease-free survival (DFS), and overall survival (OS). Patients who received primary surgical treatment for epithelial ovarian cancer in our clinic between 2000 and 2019 were retrospectively scanned through patient files, electronic databases, and telephone calls. One hundred forty-two eligible patients were included in the study, their tumoral tissues were examined to determine MT1 and MT2 expression by immunohistochemical methods. The percentage of receptor-positive cells and intensity of staining were determined. MT1 receptor expression (P = 0.002 for DFS and P = 0.002 for OS) showed a significant effect on DFS and OS. MT2 expression had no effect on survival (P = 0.593 for DFS and P = 0.209 for OS). The results showed that the higher the MT1 receptor expression, the longer the DFS and OS. It is suggested that melatonin should be considered as adjuvant therapy for ovarian cancer patients in addition to standard treatment, and clinical progress should be observed.

Mesonephric Adenocarcinoma of the Uterine Corpus: A Report on 2 Cases With Comparison to Its Cervical Counterpart

Mesonephric adenocarcinoma (MA) is a rare tumor of the female genital tract that develops in the uterine cervix. Recently, a few cases of MA arising from the uterine body have been reported, whereas the differences between these 2 entities remain unknown. Two uterine MAs and 1 cervical MA were included in this study. In uterine MA, there was an admixture of various growth patterns with tubular, glandular, slit-like, papillary, and solid architectures. Both tumors extensively involved the endometrium, while no mesonephric remnants were noted. Immunostaining was diffusely positive for TTF-1, while there was only focal staining for GATA3. KRAS somatic mutation was present in both uterine cases. In cervical MA, the tumor also had different growth patterns but no endocervical mucosa involvement. A residual mesonephric duct was present. GATA3 showed diffuse staining, but TTF-1 was totally negative. Therefore, uterine MA was not entirely consistent with its cervical counterpart in both morphologic characteristics and immunostaining.

An Expanded Series of Pilomatrix-like High-grade Endometrioid Carcinoma (PiMHEC), Including Both MMR Deficient and MMR Proficient Cases

Evaluation of Lineage/Site-specific Nuclear Immunohistochemical Markers SATB2, Cyclin D1, SALL4, and BCOR in High-grade Endometrial Carcinomas

Poorly differentiated malignant neoplasms involving the gynecologic tract routinely include a poorly differentiated endometrial carcinoma (EC) in the differential diagnosis. Some nuclear lineage/site-specific immunohistochemical markers are utilized in this diagnostic setting including SATB2, cyclin D1, SALL4, and BCOR, but their specificity and use in small samples are not clear across the spectrum of ECs. Cases of undifferentiated/dedifferentiated endometrial carcinomas (UEC/DDEC), clear cell carcinoma (CCC), uterine serous carcinoma (USC), FIGO grade 3 endometrial endometrioid carcinoma (EEC), and uterine carcinosarcoma (UCS) were identified and diagnoses confirmed. Whole-section immunohistochemical stains for SATB2, cyclin D1, SALL4, BCOR, and PAX8 were performed. A total of 113 cases were utilized: 15 CCC, 26 EEC, 19 UCS, 22 USC, and 31 UEC/DDEC. Cases were distributed across both low (49%) and high (51%) FIGO clinical stages. SATB2 was expressed by UCS (8/19, 42%), EEC (10/26, 38%), UEC/DDEC (11/30, 37%), and USC (6/22, 27%). Cyclin D1 was expressed by EEC (24/26, 92%), USC (17/22, 77%), UEC/DDEC (15/20 EEC component, 75%; 22/30 UEC, 73%), UCS (10/16 carcinoma, 63%; 11/19 sarcoma, 58%), and CCC (8/15, 53%). SALL4 was expressed most frequently by UEC/DDEC (12/30, 40%), but also USC (7/22, 32%), EEC (5/26, 19%), and UCS (4/16 carcinoma, 25%; 3/19 sarcoma, 16%). BCOR was expressed at low levels in 2 USC, 2 UEC/DDEC, and 2 UCS. PAX8 was generally positive but showed lower expression in UEC/DDEC (17/30, 57%) and in the sarcomatous portions of UCS (6/19, 32%). SATB2, cyclin D1, SALL4, and BCOR stain variable numbers of poorly-differentiated EC and must be carefully interpreted within morphologic and clinical context.

Endometrial Mesonephric-like Adenocarcinoma Presenting as an Ocular Lesion: A Case Report

Endometrial mesonephric-like carcinoma (ML-CA) is a recently recognized subtype of aggressive endometrial adenocarcinoma that is morphologically and immunophenotypically similar to mesonephric carcinoma but not typically associated with mesonephric remnants. Here, we report a case of 58-yr-old female who had a past medical history of fibroids and of irregular menstrual bleeding for ~20 yr who presented with visual disturbance. On further investigation, she was found to have a large choroidal peri-papillary tumor of the right eye. A presumptive diagnosis of choroidal melanoma was made. Right eye enucleation was performed, and microscopy revealed moderately differentiated metastatic adenocarcinoma. Further work up was advised. A uterine mass was identified on imaging followed by endometrial biopsy that showed a morphologically and immunohistochemically similar tumor to that in the eye. A hysterectomy was carried out and a malignant neoplasm with varying morphologic patterns including gland formation, solid sheets of tumor cells, cribriform, glomeruloid, spindled and papillary areas was seen. The immunohistochemical profile showed diffuse strong positivity for AE1/AE3, TTF1, P16, and vimentin. CD56, GATA3, Napsin A, and CD10 were focally positive. The neoplastic cells were negative for the following markers ER, PR, WT1, calretinin, and synaptophysin. PDL-1 was negative and mismatch repair protein was proficient. An identical KRAS mutation was detected in both the uterine corpus and ocular tumors. The findings are in keeping with a uterine mesonephric-like adenocarcinoma with an ocular metastasis. An Oncomine Focus—Mutation profile, Thermo-Fisher Scientific Inc., a 60 gene oncologic panel, performed on the ocular tumor, revealed no further mutations.

White Adipocytes of the Uterine Cervix Tend to Appear in Women of Older Age, Postmenopause Status, and Higher Body Mass Index

The human uterine cervix consists mainly of epithelium and stroma, including smooth muscle cells and fibrovascular tissues. Fat cells in the uterine cervix have been rarely reported, and the only previous research article has shown that intracervical adipocytes are unrelated to clinical factors. The aim of this study was to investigate the frequency of fat cells in the uterine cervix, as well as to evaluate the relationship between intracervical adipocytes and clinicopathologic factors. We retrospectively selected 405 cases in Japanese women who received cervical conization at our hospital between 2003 and 2017. Cervical conization was not performed during pregnancy or within 1 yr after childbirth. The prepared histologic specimens for pathologic diagnosis were available in all cases. Age, menopause status, body mass index, gravidity, and parity were selected clinical factors, which were obtained in 214 patients. The mean patient age was 42 yr (range, 22–80 yr). Intracervical white adipocytes were observed in 13% of patients (53/405), with no brown adipocytes detected. The existence of intracervical adipocytes was significantly correlated to older age (P<0.0001), postmenopause status (P<0.0001), and higher body mass index (P=0.0018). Intracervical adipocytes might undergo adipocytic metaplasia from cervical stromal cells in accordance with aging, postmenopause status, or weight gain. Our result also suggest that cervical malignancy involving fat cells does not necessarily imply parametrial invasion.

Correlation Between p16/Ki-67 Expression and the Grade of Cervical Intraepithelial Neoplasias

Interpretation of histopathology of cervical premalignant lesions suffers from marked interobserver variability due to its subjective nature. We aimed to evaluate the usefulness of the biomarkers p16 and Ki-67 in improving the diagnostic accuracy of cervical histopathology and assess the correlation between p16 expression and human papillomavirus test in different grades of cervical intraepithelial neoplasia (CIN). Cervical tissue specimens with a diagnosis of CIN 1 or worse (CIN 1+) on hematoxylin and eosin staining were selected for immunohistochemistry (IHC) staining for p16 and Ki-67. The IHC slides were examined by a gynecologic pathologist along with a review of hematoxylin and eosin slides. The review histopathology diagnosis was used to correlate with the IHC results. We observed that the proportion of women with overexpression of p16 increased with increasing histologic severity: 0% in women with normal histology; 33.3% in women with CIN 1; 58.1% in women with CIN 2; and 73.8% in women with CIN 3. Among the human papillomavirus–positive women, 76.3% (58/76) women with CIN 2/CIN 3 expressed p16, and only 8.9% (4/45) women with normal histopathology or CIN 1 expressed the same. A combination of p16 positivity and abnormal expression of Ki-67 beyond the lower third of the epithelium was observed in 0% of normal/CIN 1 and 60.5% (40/66) of CIN 3 detected on routine histopathology. We concluded that dual staining could be used as an adjunctive test to improve the diagnostic accuracy of histopathology. In addition, p16/Ki-67 IHC has a role in guiding management decisions in cases with discordant colposcopy and histopathology diagnoses.

PD-L1 Expression Correlates With Young Age and CD8+ TIL Density in Poorly Differentiated Cervical Squamous Cell Carcinoma

Management options are limited in advanced or recurrent cervical carcinoma. The Food and Drug Administration has recently approved programed cell death-1 (PD-1)/PD-ligand-1 (PD-L1) inhibitors for the treatment of advanced PD-L1 positive cervical cancer. We studied PD-L1 expression in cervical squamous cell carcinoma (CSCC) samples initially on a The tissue microarray and then in full-tissue sections from poorly differentiated (grade 3) cancers. Tissue microarray was composed of 45 grade 3 and 2 (moderately differentiated) tumors. PD-L1 expression was evaluated as categorical data and by obtaining combined positive score of neoplastic and mononuclear inflammatory cells. In tissue microarray samples PD-L1 expression was higher in poorly differentiated cancers compared with grade 2 tumors by immunohistochemistry. Full-tissue sections from grade 3 CSCC (n=22) were stained with PD-L1, CD8, and VEGF antibodies. Poorly differentiated CSCC samples had diffuse (≥50%) and focal/patchy staining patterns. The latter pattern showed localized tumor-stroma interface staining in 5 samples with low combined positive score. Importantly, younger patients (median=36) had tumors with higher expression. PD-L1 expression was associated with larger tumor size and absent lymphovascular invasion. In addition, CD8+ tumor-infiltrating lymphocyte density within the neoplastic tissue matched with PD-L1 levels. The overall survival rates did not correlate with PD-L1 expression. However, in early-stage disease high CD8+ tumor-infiltrating lymphocyte density within the peritumoral stroma was associated with better survival outcomes in multivariate analysis. PD-L1 expression and CD8+ tumor-infiltrating lymphocyte density may be useful to define a subgroup of patients with relatively better prognosis in poorly differentiated CSCC. It is warranted to validate our results in a larger sample size.

Borderline With Bad Behavior: An Unusual Low-grade Serous Carcinoma With Dedifferentiation From a Serous Borderline Tumor

The pathogenesis of serous ovarian tumors has been extensively investigated, with a dualistic model dividing these cancers into 2 groups. Type I tumors, including low-grade serous carcinoma, is characteristic for concurrent presence of borderline tumors, less atypical cytology, relatively indolent biologic behavior, and molecular aberrations related to the MAPK pathway with chromosomal stability. Meanwhile, type II tumors, such as high-grade serous carcinoma, are notable for no significant association with borderline tumors, higher grade cytology, more aggressive biologic behavior, and TP53 mutations along with chromosomal instability. We describe a case of morphologic low-grade serous carcinoma with focally increased cytologic atypia arising in serous borderline tumors involving both ovaries, which demonstrated highly aggressive behavior despite several years of surgical and chemotherapeutic management. Each recurrent specimen contained more uniform higher grade morphology than what was seen in the original specimen. Immunohistochemical and molecular studies in both the original tumor and the most recent recurrence demonstrate identical mutations in the MAPK genes, but with additional mutations in the latter, notably an acquisition of a variant of possible clinical significance in the SMARCA4 gene, which is associated with dedifferentiation and aggressive biologic behavior. This case challenges our current and still evolving understanding of the pathogenesis, biologic behavior, and expected clinical outcome of low-grade serous ovarian carcinomas. It also underscores the need for further investigation into this complicated tumor.

Genomic Characterization of HPV-related and Gastric-type Endocervical Adenocarcinoma: Correlation With Subtype and Clinical Behavior

The majority of endocervical adenocarcinomas (EAs) are caused by human papillomavirus (HPV). Gastric-type EA, the second most common EA and unrelated to HPV, is biologically different with a more aggressive clinical course. Our knowledge of the molecular fingerprint of these important EA types and its role in diagnosis, prognosis and management is still evolving. Thus, we sought to evaluate the genomic profile of HPV-related and gastric EA. Clinical information including patient outcome was gathered for 56 tumors (45 HPV-associated and 11 gastric-type) surveying evaluated by a targeted massively parallel sequencing assay (OncoPanel platform) which surveys exonic DNA sequences of 447 cancer genes and 191 regions across 60 genes for rearrangement detection. KRAS, TP53, and PIK3CA were the most commonly mutated genes (10, 10, and 9 cases, respectively). Alterations in TP53, STK11, CDKN2A, ATM, and NTRK3 were significantly more common in gastric-type EA (P<0.05, Fisher exact test). Disease recurrence and/or death occurred in 14/49 (29%) cases with clinical information available 7 HPV-related (18% of HPV-related cases with clinical information available) and 7 gastric-type (64% of gastric-type cases with clinical information available). Tumors associated with adverse outcome, regardless of histotype, more commonly had alterations in KRAS (2 HPV-related, 4 gastric-type), GNAS (3 HPV-related, 1 gastric-type), and CDKN2A (0 HPV-related, 3 gastric type) compared with indolent-behaving cases (P<0.05, Fisher exact test). A total of 8/56 (14%) tumors harbored at least one actionable mutation; of these, 6 (75%) were associated with recurrence and/or cancer-related death. Copy number variations were detected in 45/56 cases (80%). The most frequent were chromosome 20 gain and 16q loss, identified in 7 cases each (all HPV-associated EA). The mutational profile of EA is diverse and correlates with clinical behavior and EA subtype. Thus, targeted sequencing assays can potentially serve as a diagnostic and prognostic tool. It can also identify targetable alterations, which may benefit patients with recurrent/metastatic disease.

Telangiectatic Squamous Cell Carcinoma of Uterine Cervix: A Previously Undescribed Variant of Squamous Cell Carcinoma

Squamous cell carcinoma of the uterine cervix is the second most common malignancy in women worldwide. We describe an unusual telangiectatic variant of squamous cell carcinoma in a 53 yr old woman. The tumor showed the usual morphologic features of a poorly differentiated keratinizing squamous cell carcinoma with >75% tumor area showing cavernous hemangioma like ectatic spaces filled with blood. The blood-filled spaces lacked an endothelial lining as evidenced by negativity for CD31 and CD34. This unusual variant has not been reported previously. Awareness of this entity is necessary for avoiding confusion with vascular tumors such as hemangiomas and angiosarcoma.

Cervical Mesonephric Adenocarcinoma With Novel FGFR2 Mutation

Mesonephric adenocarcinoma is a rare tumor, accounting for <1% of cervical cancers. Well-differentiated mesonephric adenocarcinoma can be difficult to distinguish from diffuse mesonephric hyperplasia. Herein, we report a case of well-differentiated mesonephric adenocarcinoma with an FGFR2 mutation not previously reported in the literature. Nonselective tyrosine kinase inhibitors or FGFR2 inhibitors may represent options for targeted therapy.

Expression and Clinical Significance of Nicotinamide N-Methyltransferase in Cervical Squamous Cell Carcinoma

Nicotinamide N-methyltransferase (NNMT) is a cytosolic enzyme, overexpressed in various human malignancies. It is associated with cancer progression and resistance to treatment. The role of NNMT in cervical cancer has not been studied thus far. We aimed to evaluate expression of NNMT in cervical squamous cell carcinoma (SCC) and investigate its clinical significance. NNMT expression was assayed by use of immunohistochemistry in 61 cases of SCC, 11 cases of high-grade squamous intraepithelial lesion, 17 cases of low-grade squamous intraepithelial lesion, and 51 benign cervical tissues. NNMT immunoreactivity was scored based on staining intensity and percentage of positively stained cells. The expression of NNMT was significantly higher in SCC than in benign tissue, low-grade squamous intraepithelial lesion, and high-grade squamous intraepithelial lesion (P<0.001). NNMT expression in benign tissue was significantly lower than in low-grade squamous intraepithelial lesion and high-grade squamous intraepithelial lesion. When stratified according to stage, NNMT expression was significantly higher in patients with stage III and IV than those in stage I and II disease (P=0.009). For all stages, patients with metastatic pelvic or para-aortic lymph nodes had significantly higher NNMT expression than patients without nodal involvement (P=0.001). Although preliminary, this is the first study to detect overexpression of NNMT in SCC and increased expression associated with advanced stage and metastatic lymph nodes. NNMT should be investigated further in cervical cancer as a potential therapeutic target and a prognostic indicator.

The Genomic Landscape of Vulvar Squamous Cell Carcinoma

Vulvar squamous cell cancer (VSC) accounts for 90% of vulvar cancers. Next-generation sequencing studies of VSC imply human papillomavirus (HPV) and p53 status play separate roles in carcinogenesis and prognosis. We sought to describe the genomic landscape and analyze the immunologic profiles of VSC with respect to HPV and p53 status. A total of 443 VSC tumors underwent tumor profiling. Next-generation sequencing was performed on genomic DNA isolated from formalin-fixed paraffin-embedded tumor samples. PD-L1, microsatellite instability were tested by fragment analysis, IHC, and next-generation sequencing. Tumor mutational burden—high was defined as >10 mutations per MB. HPV 16/18 positive (HPV+) status was determined using whole exome sequencing on 105 samples. Three cohorts were identified from 105 samples with known HPV: HPV+, HPV−/p53wt, and HPV−/p53mt. Where HPV and p53 status were examined, TP53 mutations were exclusive of HPV+ tumors. In all, 37% of samples were HPV+. Among the 66 HPV− tumors, 52 (78.8%) were HPV−/p53mt and 14 (21.2%) were HPV−/p53wt. The HPV−/p53wt cohort had a higher rate of mutations in the PI3KCA gene (42.9% HPV−/p53wt vs 26.3% HPV+ vs. 5.8% HPV−/p53mt, q=0.028) and alterations in the PI3K/AkT/mTOR pathway (57.1% HPV−/p53wt vs. 34.2% HPV+ vs. 7.7% HPV−/p53mt, q=0.0386) than the other 2 cohorts. Ninety-eight VSC tumors with HPV16/18 information underwent transcriptomic analysis and immune deconvolution method. No differences were observed in immune profiles. The HPV−/p53wt VSC tumors had significantly higher rates of mutations in the PI3KCA gene and alterations in the PI3K/AkT/mTOR pathway, a potential target that merits further investigation in this subgroup.

Microcystic Adnexal Carcinoma (MAC) and Eccrine Cutaneous Mixed Tumor (ECMT): 2 Cases of Rare HPV-independent Vulvar Cutaneous Adnexal Tumors

Microcystic adnexal carcinoma (MAC) and eccrine cutaneous mixed tumor (ECMT) are both cutaneous adnexal tumors that may occur in the vulvar region, but are very rare at this site. Consequently, they may not enter the differential diagnosis of vulvar lesions for gynecologic pathologists in a subspecialized practice setting. Here we report a case of MAC and a case of ECMT recently diagnosed at our institution and underscore key histologic and immunophenotypic features of each lesion that can assist in their correct identification. Both MAC and ECMT have a tubular to corded pattern of lesional cells within a desmoplastic to chondromyxoid stroma. However, MAC shows true eccrine sweat duct differentiation, characterized by 2 SOX10 negative cell layers, including an outer p63+/p40+/EMA− basal cell layer and an inner p63−/p40−/EMA+ ductal layer. The main differential diagnostic considerations for vulvar MAC include other cutaneous adnexal tumors with true eccrine sweat duct differentiation, namely syringoma and squamoid eccrine ductal carcinoma (SEDC). Conversely, ECMT is characterized by a single SOX10+ cell population without immunoreactivity for p63 or p40. The main differential diagnostic considerations for ECMT include the apocrine variant of cutaneous mixed tumor (ACMT)—the cutaneous analog of salivary gland pleomorphic adenoma—and other SOX10+ salivary gland-type neoplasms. Unlike the recently described vulvar analog of HPV-associated multiphenotypic sinonasal carcinoma, neither MAC nor ECMT are HPV-associated and both are therefore p16 negative. In summary, we report one case each of vulvar MAC and ECMT and discuss the key histologic features and ancillary testing results that can help to differentiate these lesions from their morphologic mimics.

Role of Immunohistochemical Analysis of p16 and p53 in Vulvar Carcinoma

Tumor human papillomavirus (HPV) status is an important prognostic factor in vulvar cancer as indicated in the latest WHO classification of female genital tract tumors. Immunohistochemical detection of p16 is well established as a surrogate biomarker for tumor HPV association, including squamous cell carcinomas of the vulva. HPV-independent vulvar carcinomas are heterogeneous with 2 subcategories according to the TP53 mutation status. Therefore, the simultaneous use of p53 and p16 immunohistochemistry is recommended for accurate subclassification of vulvar squamous cell carcinomas. However, the role of molecular analytical tools, in particular RNA ISH and TP53 sequencing, is not so clear. This study aimed to investigate the performance of p53 and p16 immunohistochemistry for the diagnosis of vulvar carcinomas in comparison to TP53 mutation analysis and HPV RNA ISH. We analyzed 48 vulvar carcinomas in a tissue microarray format. Sensitivity and specificity for both methods, p16 (100% and 96%) and p53 (95% and 90%) immunohistochemistry for detection of HPV association as well as for TP53 mutations was high. Combining p16 and p53 immunohistochemistry we correctly classified all carcinomas in our series according to current WHO criteria. The sensitivity of HPV RNA ISH for the detection of HPV association was lower compared to p16 immunohistochemistry. Rare HPV-associated cases with TP53 mutation and HPV-independent tumors with p16 overexpression are discussed. In summary, the combined use of p16 and p53 immunohistochemistry for subclassification of vulvar carcinomas is justified in daily practice. Molecular tests should be restricted to rare cases with ambiguous clinicopathologic or immunohistochemical features.

TRPS1 Is Consistently Expressed in Hidradenoma Papilliferum

TRPS1 is a novel immunohistochemical marker, so far quite specific and sensitive for breast cancer and especially useful for the diagnosis of triple-negative breast cancer. TRPS1 expression has recently been reported in normal skin appendages, as well as in a variety of benign and malignant cutaneous tumors, including adnexal tumors. However, it has not yet been reported in hidradenoma papilliferum (papillary hidradenoma), a benign adnexal neoplasm, accepted to originate from mammary-like glands in the vulvar or anogenital region of middle-aged women. We report consistent nuclear expression of TRPS1 in the epithelium of 9/9 cases of hidradenoma papilliferum, while in 2/2 cases with foci of oxyphilic metaplasia, these foci were consistently negative for TRPS1 immunohistochemistry. Our findings are in line with the theory that hidradenoma papilliferum is derived from mammary-like glands and showed that TRPS1 can be an additional sensitive immunohistochemical marker for hidradenoma papilliferum.

Human Papillomavirus–Associated Multiphenotypic Carcinoma: First Description of a Vulval Case

Human papillomavirus (HPV)–associated multiphenotypic sinonasal carcinoma is a rare and recently described epithelial neoplasm exhibiting myoepithelial differentiation and morphological overlap with salivary gland neoplasms, especially adenoid cystic carcinoma; it is commonly associated with HPV, especially type 33. It has mainly been reported in the nasal cavity and paranasal sinuses with a single case reported in the breast. Herein, we report the first vulval example in a 47-year-old patient who presented with a large craggy mass in the region of the Bartholin gland. The histologic features were of a high-grade carcinoma composed of basaloid cells arranged in sheets and nests, with occasional ductal formations, surrounded by densely hyalinised basement membrane-type material. There was diffuse block-type immunoreactivity with p16 and HPV genotyping revealed high-risk HPV type 16. In reporting this case, we highlight the propensity for “salivary gland-type” neoplasms to arise in the vulva, especially in the Bartholin gland, and stress that pathologists should consider salivary-type neoplasms when faced with a morphologically unusual vulval tumor.

PD-L1 Expression in HPV-associated Versus HPV-independent Invasive Vulvar Squamous Cell Carcinoma

Two etiological pathways have been implicated in the pathogenesis of vulvar squamous cell carcinoma (VSCC): a high-risk human papillomavirus (HPV)–associated route and an HPV-independent pathway characterized by TP53 mutations. Programmed cell death ligand 1 (PD-L1) has become increasingly useful in predicting the response to checkpoint inhibitor therapy in squamous cell carcinomas at various anatomical sites. This study aimed to assess the association between PD-L1 expression and the VSCC subtype to evaluate the utility of PD-L1 in prognostication and therapeutic selection based on HPV status. PD-L1 status was assessed using 3 separate metrics for the extent of PD-L1 staining in various cell types: immune cell score, tumor proportion score (TPS), and combined positive score. The study group consisted of 25 HPV-associated and 28 HPV-independent VSCCs. PD-L1 expression was positive in the majority of VSCCs according to all 3 scoring metrics (84.9% by immune cell score, 77.3% by TPS, and 90.6% by combined positive score). PD-L1 expression was observed in the majority of cases in both groups (60%–96.4%). PD-L1 expression using the TPS method was greater in HPV-independent tumors than in HPV-associated tumors (P = 0.004), and high PD-L1 expression was also more common in the HPV-independent subtype (P = 0.016 using the TPS method and P = 0.013 using the combined positive score method). Our findings contribute to the growing evidence that PD-L1 is expressed in the majority of invasive VSCCs, and thus may serve as an attractive therapeutic target. PD-L1 expression is higher in HPV-independent tumors, suggesting that this subtype may be more responsive to PD-L1 inhibitor therapy.

CXCR4 Expression and Cancer-associated Fibroblasts May Play an Important Role in the Invasion of Low-grade Endometrioid Carcinoma

Well-differentiated endometrioid carcinoma (EC) is a low-grade cancer with relatively indolent behavior. However, even with well-differentiated histology, it sometimes tends to invade extensively and shows metastatic potential, suggesting that this is a group of cancers with heterogeneous behavior. In contrast, due to its tendency for younger onset, the treatment strategy for EC frequently considers fertility preservation, highlighting the need for a more accurate evaluation of myometrial invasion through biopsy and imaging diagnostics. We previously reported the involvement of the CXCR4–CXCL12 and CXCL14 axes in EC invasion. Accordingly, we investigated whether CXCR4 expression could reflect invasive potential and explored its interaction with cancer-associated fibroblasts that produce chemokines in the tumor microenvironment. Immunohistochemical expression of CXCR4 was assessed in 71 cases of EC (14 of EC confined to the endometrium and 57 of myoinvasive EC), 6 cases of endometrial intraepithelial neoplasia, and 42 cases of noncarcinomatous conditions. CXCR4 expression was significantly higher in myoinvasive EC than in noncancerous conditions, endometrial intraepithelial neoplasia, and endometrium-confined EC. By univariate and multivariate analysis, CXCR4 expression significantly reflected myometrial invasion. CXCR4 expression in the biopsied and resected specimens correlated weakly positively. Invasion and wound-healing assays were performed culturing an EC cell line in a cancer-associated fibroblast-conditioned medium. The invasion and wound-healing potentials were dependent on CXCR4 and cancer-associated fibroblast. Our study demonstrated that CXCR4 expression is an independent factor in myometrial invasion and can support diagnostic evaluation before treatment in the biopsy sample.

TP53 Mutation-driven Stratified Mucin-producing Carcinoma Coexisting With Squamous Cell Carcinoma of the Vulva: A Case Study

Associated with high-risk human papillomavirus infection, invasive stratified mucin-producing carcinoma is a recently characterized adenocarcinoma of the cervix. It often occurs in association with adjacent stratified mucin-producing intraepithelial lesion. Differentiated vulvar intraepithelial neoplasia and related invasive squamous cell carcinoma often arise in background vulvar lichen sclerosus with TP53 mutation as the underlying molecular signature. We present a unique case of vulvar invasive stratified mucin-producing carcinoma-like component coexisting with invasive squamous cell carcinoma in a 64-year-old woman. Both neoplastic components were proven TP53-driven processes arising in the background of differentiated vulvar intraepithelial neoplasia and lichen sclerosus. The invasive stratified mucin-producing carcinoma-like component behaved aggressively in this case, evidenced by the presence of lymphovascular invasion and inguinal lymph node metastasis.

HPV-associated Vulvar Intraepithelial Carcinoma With Sebaceous Differentiation: Report of 2 Cases

Sebaceous carcinoma (SC) is a malignant neoplasm demonstrating sebocytic differentiation, commonly in the periocular area. Sebocytic differentiation is recognized by multivesicular cytoplasmic clearing with frequent nuclear scalloping. The vesicles can be highlighted by immunohistochemical stains against the perilipin family proteins including adipophilin. Extraocular SC is uncommon but well reported, often in the setting of Muir-Torre syndrome; however, vulvar SC is exceptionally rare. The literature review yielded only 12 prior cases of vulvar SC, all of which showed invasion. Here we report 2 additional similar cases from 2 different institutions of an intraepithelial carcinoma with sebaceous differentiation. Histologic examination of multiple specimens from both patients showed similar features: a multifocal intraepithelial basaloid nodular neoplasm sparing the basal layer with occasional pagetoid spread. The tumor cells demonstrated a high nuclear to cytoplasmic ratio, mitoses, variably foamy vacuolated cytoplasm, and nuclear indentation. Multiple specimens from both patients showed evidence of sebaceous differentiation (substantiated by adipophilin positivity in a membranous vesicular pattern in case 1 and by androgen receptor and epithelial membrane antigen positivity in case 2), and squamous differentiation (substantiated by p63/p40 and weak CK 5/6 expression), as well as human papillomavirus (HPV) association (substantiated by p16 block positivity and detection of high-risk HPV by in situ hybridization). One case was a true in situ lesion without evidence of invasion, and the other case was predominantly an in situ carcinoma with prominent adnexal extension and focal superficial invasion of <1 mm seen in one of multiple specimens. To our knowledge, these 2 cases are the first to show a vulvar SC/carcinoma with sebaceous differentiation that is predominantly limited to the epidermis, and the first documentation of HPV infection in vulvar sebaceous neoplasms. Vulvar intraepithelial carcinoma with sebaceous differentiation is the umbrella term we chose for this entity. Whether this is a true SC in situ that is HPV positive/driven, or a vulvar intraepithelial neoplasia with sebaceous differentiation, is not entirely clear. We emphasize the importance of looking for this morphology to avoid misclassification. Due to the rarity of cases, optimal treatment at this site has not been established.

Cervical Adenosquamous Carcinoma: Detailed Analysis of Morphology, Immunohistochemical Profile, and Outcome in 59 Cases

Although both the 2014 and 2020 World Health Organization (WHO) criteria require unequivocal glandular and squamous differentiation for a diagnosis of cervical adenosquamous carcinoma (ASC), in practice, ASC diagnoses are often made in tumors that lack unequivocal squamous and/or glandular differentiation. Considering the ambiguous etiologic, morphologic, and clinical features and outcomes associated with ASCs, we sought to redefine these tumors. We reviewed slides from 59 initially diagnosed ASCs (including glassy cell carcinoma and related lesions) to confirm an ASC diagnosis only in the presence of unequivocal malignant glandular and squamous differentiation. Select cases underwent immunohistochemical profiling as well as human papillomavirus (HPV) testing by in situ hybridization. Of the 59 cases originally classified as ASCs, 34 retained their ASC diagnosis, 9 were reclassified as pure invasive stratified mucin-producing carcinomas, 10 as invasive stratified mucin-producing carcinomas with other components (such as HPV-associated mucinous, usual-type, or ASCs), and 4 as HPV-associated usual or mucinous adenocarcinomas with benign-appearing squamous metaplasia. Two glassy adenocarcinomas were reclassified as poorly differentiated HPV-associated carcinomas based on morphology and immunophenotype. There were no significant immunophenotypic differences between ASCs and pure invasive stratified mucin-producing carcinomas with regard to HPV and other markers including p16 expression. Although limited by a small sample size, survival outcomes seemed to be similar between all groups. ASCs should be diagnosed only in the presence of unequivocal malignant glandular and squamous differentiation. The 2 putative glassy cell carcinomas studied did not meet our criteria for ASC and categorizing them as such should be reconsidered.

Unusual Manifestations of Vulval Paget Disease

Vulval extramammary Paget disease (vEMPD) is an uncommon epithelial malignancy that may arise within the vulva (primary vEMPD) or represent vulval skin involvement by a noncutaneous carcinoma (secondary vEMPD). Primary vEMPD is most often an in situ carcinoma arising within the epidermis but may be associated with dermal invasion (invasive vEMPD) or represent intraepidermal spread of an adenocarcinoma originating in vulval skin adnexa or anogenital mammary-like glands. The latter, termed mammary gland-like adenocarcinoma (MGLA), exhibits morphologic, immunohistochemical, and molecular features of various breast carcinomas but, as far as we are aware, the metaplastic variant of MGLA has not been reported on the vulva. We report 2 cases of metaplastic MGLA of the vulva with associated Paget disease and postulate that some cases of vulval MGLA may arise from Paget disease rather than originating in mammary-like glands. We also report a unique case of secondary vEMPD resulting from spread of urothelial carcinoma in situ that subsequently progressed to invasive urothelial carcinoma within the vulva.

ORF1p Is a Potential Novel Diagnostic Marker for Differentiated Vulvar Intraepithelial Neoplasia

Accurate diagnosis of differentiated vulvar intraepithelial neoplasia (dVIN) can be challenging as histomorphologic features may be subtle and overlap with nondysplastic lesions. In practice, aberrant p53 expression supports the diagnosis, but a substantial percentage retains wild-type p53. Recently, the retrotransposon long interspersed nuclear element 1 has been detected in distinct cancer types. We have now investigated the expression of the long interspersed nuclear element 1 encoded protein ORF1p in dysplastic and nondysplastic vulvar samples to assess its diagnostic value. Specimens of dVIN (n=29), high-grade squamous intraepithelial lesions (n=26), inflammatory vulvar lesions (n=20), lichen sclerosus (n=22), and normal vulvar epithelia (n=29) were included. ORF1p and p53 expression was determined using immunohistochemistry. The majority of dVIN [27/29 (93%)] and high-grade squamous intraepithelial lesions [20/26 (77%)] showed distinct (i.e. moderate or strong) ORF1p expression in the basal and suprabasal or all epithelial layers, respectively. Of note, ORF1p was present in all 4 cases of dVIN with wild-type p53 staining pattern. In contrast, ORF1p was negative or weakly expressed in most inflammatory lesions [14/20 (70%)] and lichen sclerosus [18/22 (82%), P<0.001]. Normal control epithelium exhibited negative staining in all cases. In conclusion, ORF1p might be a useful diagnostic marker for dVIN, especially in cases with retained wild-type p53.

Vulvar Squamous Cell Carcinoma With Sarcomatoid Features are HPV-independent Lesions: A Subset are Also Associated With TP53-independent Lesions and Radiation Therapy

Vulvar squamous cell carcinoma of the vulva (VSCC) with sarcomatoid features is a rare variant characterized by spindle-cell morphology and occasional heterologous elements. They are difficult to evaluate due to rarity and lack unified nomenclature and histopathologic criteria. Eight cases of sarcomatoid VSCC were retrieved from archival electronic medical records from 2013 to 2021. Patients often presented at a mean age of 78-yr-old at stage FIGO (2018) III or above. The mean greatest diameter was 4.5 cm and mean depth of invasion was 11.5 mm. Spindle cells exhibited fascicular, nested, and cord-like growth patterns, though a haphazard arrangement or a mix of patterns was frequently observed. The sarcomatoid component frequently arose in the context of prior conventional VSCC treated with radiation therapy (n=6, 75% and chemotherapy (n=5, 63%) with latency periods of 5.2 and 5.4 yr, respectively. Associated lesions included differentiated vulvar intraepithelial neoplasia (n=4, 50%), lichen sclerosus (n=5, 63%), and vulvar acanthosis with altered differentiation (n=1, 13%). Immunohistochemistry showed that VSCC with sarcomatoid features aberrantly expressed p53 (n=4, 60%) through diffuse overexpression or null-type patterns. P16 was invariably negative in all cases. These findings suggest that VSCC with sarcomatoid features does not arise from the HPV-related carcinogenic pathway, and that a subset may also arise from the TP53-independent pathway. Recognizing sarcomatoid morphology in VSCC is important since it may confer an elevated risk of nodal metastasis and poorer survival. Larger studies are required to assess the etiology and prognostic implications of VSCC with sarcomatoid features.

p53/CK17 Dual Stain Improves Accuracy of Distinction Between Differentiated Vulvar Intraepithelial Neoplasia and Its Mimics

Accurate diagnosis of differentiated vulvar intraepithelial neoplasia (dVIN) is challenging, in part due to the sometimes subtle nature of its atypia. Many dVIN lesions demonstrate aberrant p53 staining; however, staining patterns overlap between dVIN and benign/reactive entities. We evaluate a p53/CK17 dual stain in an initial cohort of dVIN (n=30), benign vulvar skin (n=5), lichen sclerosus (LS, n=10), lichen simplex chronicus (LSC, n=10), and pseudoepitheliomatous hyperplasia (PEH, n=10). In the initial cohort, aberrant p53 staining was seen only in dVIN (50%, 15/30). Equivocal p53 staining patterns were seen in dVIN (37%, 11/30), LS (50%, 5/10), LSC (40%, 4/10), and PEH (40%, 4/10). All 30 dVIN cases were positive for CK17 (strong partial-thickness or full-thickness staining), but positive CK17 staining was also seen in LS (70%, 7/10), LSC (50%, 5/10), and PEH (100%, 10/10). In the initial cohort, the combination of aberrant p53 and positive CK17 was seen only for dVIN (50%, 15/30). Forty cases of LS with known follow-up (20 with progression to dVIN, 20 without) were stained to assess prognostic value. Three LS cases showed aberrant p53 staining with CK17 positivity; all progressed to dVIN. Equivocal p53 staining and CK17 positivity were seen in cases with and without progression. The p53/CK17 dual stain is more diagnostically useful than either stain alone. Negative/focal staining for CK17 argues against a diagnosis of dVIN, while aberrant p53 staining with CK17 positivity strongly supports the diagnosis.

Acantholytic Squamous Cell Carcinoma Arising From Lichen Sclerosus: A Rare Case Affecting Vulvar Skin

We present the case of an 82-year-old female with acantholytic squamous cell carcinoma affecting vulvar skin. The patient had a history of perineal lichen sclerosus for 5 years before presentation. She was referred to a dermatologist for intractable severe pain associated with the lesions. Biopsies showed an infiltrative squamous cell carcinoma with histology consistent with the acantholytic subtype. Acantholytic squamous cell carcinoma is a rare histologic variant characterized by dyscohesive keratinocytes with pseudoglandular formation and dyskeratosis. It is associated with sun-damaged skin and most commonly occurs in the head and neck of elderly men. Few cases have been reported at nondermal sites and non–sun-exposed dermis. The patient underwent a radical vulvectomy and bilateral inguinal node dissection. The 1.6 cm tumor was diffusely acantholytic and pseudoglands were present. The tumor cells were diffusely positive for p63 immunohistochemical stain. As expected at this site, there was no solar elastosis identified histologically. However, vulvar intraepithelial neoplasia and chronic lichen sclerosus were apparent. This case represents a rare histologic subtype of squamous cell carcinoma in an unusual site associated with lichen sclerosus instead of solar elastosis.

Reproducibility of Morphologic Parameters of the International Endocervical Adenocarcinoma Criteria and Classification System and Correlation With Clinicopathologic Parameters: A Multi-Institutional Study

Endocervical adenocarcinomas (ECAs) have been recently reclassified according to their morphologic features linked to etiology by the International Endocervical Adenocarcinoma Criteria and Classification (IECC) and this system is adopted by WHO 2020. This classification separates the ECAs as human papillomavirus (HPV)-associated (HPVA) and HPV-independent (HPVI) subtypes. According to WHO 2020, high risk (HR)-HPV association can be histologically recognized by the presence of luminal mitoses and apoptosis. Therefore, investigating the reproducibility of the morphologic criteria of this new classification will be important in observing the recognizability of tumor types. Full slide sets of 94 ECAs were collected from 4 institutions in Turkey and reclassified on the basis of IECC/WHO 2020 criteria and the presence or absence of HR-HPV. HR-HPV presence was confirmed by HPV DNA in situ hybridization, p16 immunohistochemistry and in conflicted cases with real time-polymerase chain reaction. The final diagnoses were given based on the combination of the histologic evaluation and ancillary test results. Our cohort consisted of 73.4% HPVA and 26.6% HPVI cases. According to the WHO 2020 criteria 92.7% of HPVAs and 88% of HPVIs were easily classified. HPV DNA in situ hybridization was positive in 91.3% of the HPVAs and p16 was positive in all HPVAs, and also positive in 8% of the HPVIs. In conclusion, most of the ECAs can be diagnosed by their characteristic morphologic features by the WHO 2020 criteria. However, we want to emphasize that mitosis/apoptosis criteria may not be helpful especially in mucinous ECAs and ancillary tests for HR-HPV should be used in challenging cases.

The Immune Checkpoint Inhibitor LAG-3 and Its Ligand GAL-3 in Vulvar Squamous Neoplasia

Vulvar squamous cell carcinoma (vSCC), although rare, carries significant morbidity and a high rate of recurrence. Treatment options beyond surgical excision remain limited. Lymphocyte activation gene-3 (LAG-3) and its binding partner galectin-3 (GAL-3) are an immuno-inhibitory checkpoint pair that represent potential immunotherapy targets for the treatment of vSCC. This study examined the expression of LAG-3 and GAL-3 alongside programmed cell death ligand-1 expression in invasive SCC and vulvar intraepithelial neoplasia (VIN) by immunohistochemical analysis of formalin-fixed paraffin-embedded tissue. A total of 35 cases were selected for evaluation: 13 VIN3 [human papillomavirus (HPV)-associated VIN/usual-type VIN], 2 differentiated VIN (dVIN), 16 HPV-associated vSCC, and 4 dVIN-associated vSCC. LAG-3+ tumor-infiltrating lymphocytes were identified in 91% (32/35) of cases of vulvar squamous neoplasia. Tumor cells were positive for GAL-3 in 71% of the vulvar neoplasia cases. HPV-associated vSCC was more likely to demonstrate GAL-3 tumoral positivity when compared with dVIN-associated vSCC (24/29 vs. 1/6, P=0.004). We observed co-expression of all 3 immunomarkers in 40% (14/35) of cases evaluated. In light of these findings, use of immunomodulatory drugs that target the LAG-3/GAL-3 pathway may be potentially beneficial in vSCC and efficacy may be increased when combined with anti-programmed cell death ligand-1 therapy.

Vulvar Adenocarcinoma of Intestinal Type: A Case Report of an Uncommon Entity

Vulvar cancer is rare and accounts for only 5% of all gynecologic cancers. Squamous cell carcinoma is the most common and makes up 90% of the cases. Vulvar adenocarcinoma usually arises in Bartholin and other vulvar glands. Primary vulvar intestinal-type adenocarcinoma is an extremely rare disease with an unclear prognosis and treatment. Its origin is still unknown, the most accepted theory suggests cloacal remnants as the source of origin. Only a few cases have been reported in the literature. We present a case of a 66-yr-old female who presented with vulvar pruritus and local discomfort, showing a 2 cm tumor located in the left labium minor in the region of vulvar fourchette. Wide vulvar excision and bilateral lymph nodes dissection were performed. Other concomitant lesions and distant extension of tumor were ruled out by positron emission tomography. Pathologic study revealed a colonic-type adenocarcinoma with typical villoglandular architecture with an irregular glandular structure composed of atypical columnar epithelium. The lesion had direct contact with epidermal surface and mainly was external without involving the dermis. Immunohistochemical analysis revealed positive staining for cytokeratin 20 and CDX2. p16 showed an abnormal diffuse and strong immunoexpression. The presence of a low-risk human papillomavirus was detected by polymerase chain reaction, therefore, the expression of p16 cannot be explained in this case by the presence of human papillomavirus. Additional studies are needed in additional cases to clarify the role of human papillomavirus in this kind of tumor.

Vulvar Basal Cell Carcinoma: Clinical and Histopathologic Features

Basal cell carcinoma (BCC) is the most frequent skin cancer but <1% of the cases develop in the vulva. Histoprognostic features of vulvar BCCs are not recognized and, consequently, the treatment of the disease is not well codified. To overcome this lack of knowledge, we have performed a retrospective analysis of vulvar BBCs to assess the value of various histological features regarding the disease outcome. In all, 19 patients surgically treated for a vulvar BCC in the Centre Hospitalier Intercommunal de Créteil from March 1, 2000 to September 26, 2019 were retrieved. Clinical and histologic features were reviewed in all cases and analyzed in comparison with disease recurrence and patient’s survival. The median age of the patients was 74 (range 54–99) yr. Tumor location on the labium majus was the most frequent (68%). None presented with a medical condition related to BCC. All the patients were treated by surgery alone, except one who benefited from additional radiotherapy. We found a significant association between tumor size and recurrences (P=0.031). Other features associated with disease outcome were tumor thickness, treatment type, and surgical margins. Recurrence was observed for tumors larger than 20 mm with a surgical margin of less than 3 mm. A combination of tumor size, thickness, and surgical margin are histoprognostic factors more significant than tumor subtype.

Vulvar Primary Cutaneous CD8+ Aggressive Epidermotropic Cytotoxic T-Cell Lymphoma

Cutaneous T-cell lymphomas may present with a clinical course that is incongruent with the associated histologic findings. Primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma classically presents as an abrupt eruption of disseminated ulcerated annular plaques with aggressive behavior and a poor prognosis. Herein we describe a vulvar primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma with a locally aggressive clinical course that was strikingly responsive to radiation therapy. As aggressive therapy involving systemic chemotherapy is indicated for primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, appropriate clinico-pathologic correlation is crucial for preventing potentially excessive or insufficient therapeutic intervention. Our case also highlights the pivotal role of both radiation therapy and infection control in the management of aggressive cutaneous vulvar lymphomas.

Secretory Carcinoma (Mammary Analogue Secretory Carcinoma) of the Vulva With ETV6 Gene Rearrangement: A Brief Report With Follow-up

Targeted Molecular Sequencing of Recurrent and Multifocal Non–HPV-associated Squamous Cell Carcinoma of the Vulva

Recurrent vulvar squamous cell carcinomas (SCCs) are a poorly understood and aggressive group of treatment-resistant neoplasms. Currently, it remains unclear whether these are in fact recurrences of the same primary tumor, or the development of entirely new tumors. Here, to address this question, we examined the mutational profile of a series of patients with recurrent or multifocal non–human papilloma virus (HPV)-associated vulvar SCC. We performed a targeted 33-gene next-generation sequencing panel on a series of 14 patients with recurrent or multifocal non–HPV-associated vulvar SCC and precursor neoplasms. This amounted to 54 cases (33 SCC, 1 verrucous carcinoma, 13 differentiated vulvar intraepithelial neoplasia, and 7 differentiated exophytic vulvar intraepithelial lesion), with 79 mutations detected altogether. TP53 [51/79 (65%)] was the most frequently mutated gene. Mutations in PIK3CA [16/79 (20%)), HRAS [6/79 (8%)], PTEN [4/79 (5%)], EGFR [1/79 (1%)], and GNAS [1/79 (1%)] were occasionally seen. Most patients with SCC [5/9 (56%)] recurrent, 4/5 (80%) multifocal] demonstrated a clonal relationship, and harbored the same mutations in the same genes in metachronous or synchronous tumors. A subset of the recurrent tumors [2/5 (40%)] recurred with additional mutations. These clonal relationships were shared between SCC and differentiated vulvar intraepithelial neoplasia in each case. By contrast, a small number of recurrent tumors [3/9 (33%)] demonstrated novel mutations, entirely different from the primary tumor. Thus, our findings suggest that recurrent non–HPV-associated vulvar SCC can arise from 2 mechanisms.

Vulvar Pilomatrix Carcinoma: Morphologic and Molecular Features

Pilomatrix carcinoma (PC) is a rare malignant variant of pilomatrixoma, a skin adnexal tumor originating from hair matrix cells. It is most often located in the head, neck region, upper back and upper extremities. PC has a locally aggressive behavior but metastasis only occur in 10% of cases. Mutations in CTNNB1, the encoding gene of beta-catenin, have been found in both pilomatrixoma and PC, but other molecular alterations are unknown. The authors present a case of PC in the clitoris, the third known reported case located on the external genitalia. The tumor followed an unusual clinical course with the development of multiple metastases. Next-generation sequencing analysis of the tumor identified, in addition to a characteristic CTNNB1 mutation, pathogenic mutations in PTEN, PIK3CA, and ARID1A, which could explain the aggressive course of the disease. The diagnostic criteria of PC and the differential diagnoses of this unusual tumor in the genital area are discussed.

Extraskeletal Myxoid Chondrosarcoma of the Vulva Confirmed by EWSR1 FISH: A Case Report and Review of the Literature

Extraskeletal myxoid chondrosarcoma of the vulva is a very rare tumor, with less than 10 cases reported in the literature. We report a case of a 45-yr-old woman with extraskeletal myxoid chondrosarcoma of the vulva confirmed by EWSR1 fluorescence in situ hybridization. Given the unusual site and prominent myxoid morphology, a broad differential diagnosis and a variety of ancillary testing was required. This article aims to review extraskeletal myxoid chondrosarcoma of the vulva, the differential diagnosis of a myxoid spindle cell neoplasm of the vulva, and the diagnostic importance of immunohistochemistry and EWSR1 fluorescence in situ hybridization.

Expanding the Morphologic, Immunohistochemical, and HPV Genotypic Features of High-grade Squamous Intraepithelial Lesions of the Vulva With Morphology Mimicking Differentiated Vulvar Intraepithelial Neoplasia and/or Lichen Sclerosus

Squamous cell carcinoma of the vulva can arise through 2 pathways: human papillomavirus (HPV)-dependent high-grade squamous intraepithelial lesions (previously termed usual vulvar intraepithelial neoplasia) or HPV-independent (differentiated vulvar intraepithelial neoplasia, dVIN). Distinguishing between the 2 types can be clinically and histologically difficult. A subset of high-grade squamous intraepithelial lesions with superimposed chronic inflammation mimicking dVIN has recently been reported; p53 shows characteristic mid-epithelial staining (with basal sparing) in such cases. The pathology databases of 2 academic institutions were searched for vulva specimens with corresponding p53 and p16 immunohistochemical stains, yielding 38 specimens (from 27 patients). In situ hybridization and multiplex polymerase chain reaction-MassArray for high-risk HPV were performed on at least 1 block from each patient. All cases resembled dVIN or lichen sclerosus morphologically, but with a higher degree of atypia. All but 1 case demonstrated mid-epithelial p53 staining with basal sparing by immunohistochemistry. All cases showed block positivity for p16 and at least patchy positivity by HPV in situ hybridization. Of the 23 cases with valid HPV DNA polymerase chain reaction results, 15 were positive and 8 were negative. Of the positive cases, HPV16 was identified in 10 cases, with other high-risk types in the remaining 5. To our knowledge, this is the largest cohort of high-grade squamous intraepithelial lesions mimicking dVIN reported to date. Prior studies reported positivity for HPV16 in all cases tested, however, we found HPV16 in only 67% of HPV positive cases. This case series highlights the importance of immunohistochemistry, and occasionally HPV in situ hybridization, for accurate diagnosis, and expands the spectrum of associated HPV types.

Atypical Non-neoplastic Changes in Anogenital Mammary-like Glands Accompanying Invasive Squamous Cell Carcinoma

Long regarded as ectopic or supernumerary breast tissue, anogenital mammary-like glands (AGMLG) are now considered a normal constituent of the anogenital area. AGMLG are presumed to be the origin for various benign and malignant lesions. Changes in AGMLG compatible with usual ductal hyperplasia and atypical ductal hyperplasia considered as precursor lesions and its presence in specimens can be explained by their role in the pathogenesis of primary extramammary Paget disease. In this report, we presented four cases of invasive squamous cell carcinoma accompanied by non-neoplastic atypical changes in ductal portions of AGMLG compatible with atypical ductal hyperplasia in breast adjacent to the carcinoma. This is a reactive phenomenon similar to that seen in apocrine/eccrine glands adjacent to squamous cell carcinoma. In a limited biopsy specimen, these areas should not be mistaken for adenocarcinoma.

Solitary Fibrous Tumor of the Vulva: Case Report of a Rare Entity and Review of Literature

Solitary fibrous tumor (SFT) is an uncommon mesenchymal tumor of fibroblastic origin, which shows a prominent hemangiopericytoma-like branching pattern. It may be found at any location and can rarely involve the female genital tract with the vulva being the most common site of involvement. This is a case report of vulvar SFT in a 47-yr-old female who presented with a slow growing vulvar mass for 3 yr. Histologic examination showed a neoplasm composed of ovoid to spindle shaped cells with hypocellular and hypercellular areas in a collagenous background. Prominent hemangiopericytoma-like vessels were identified. Immunohistochemistry showed positive staining of the tumor cells for CD34, STAT6, ER, PR, and vimentin. Immunoshistochemical staining for desmin, SMA, and S100 was negative. The majority of SFTs have a NAB2-STAT6 gene fusion on chromosome 12, resulting in nuclear STAT6 overexpression, which is a sensitive and specific immunohistochemical marker for its diagnosis. Only 25 cases of vulvar SFT have been reported in the English literature and it should be considered in the differential diagnosis of spindle cell lesions at this site.

POLE-mutated Endometrial “Carcinosarcoma”

The molecular subtype classification of endometrial carcinomas has conceptually changed our approach to this disease. However, open questions remain about how to integrate certain histotype diagnoses with the molecular subtype. We report 2 cases with morphologic suspicion for endometrial carcinosarcoma, that still fell short of the essential criteria for diagnosing carcinosarcoma. On subsequent molecular testing pathogenic POLE mutations were detected and a descriptive diagnosis of endometrial endometrioid carcinomas, low-grade with a homologous sarcoma component was rendered. This challenges the existence of POLE-mutated “carcinosarcoma.”

Synchronous Bilateral Ovarian Carcinomas With Right Mesonephric-like Adenocarcinoma and Left High-grade Serous Carcinoma: A Case Report and Review of the Literature

Mesonephric-like adenocarcinomas (MLAs) are rare neoplasms of the uterus corpus and ovary, while high-grade serous carcinoma (HGSC) is the most common and lethal epithelial ovarian malignancy. We report a case of a 56-yr-old woman who presented with bilateral solid and cystic ovarian masses. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy, lymphadenectomy, omentectomy, and peritoneal biopsies. Histopathologic examination of the bilateral ovarian masses revealed 1 ovary with MLA, and the other ovary showed HGSC in association with serous tubal intraepithelial carcinoma. The morphology, immunophenotypes, and molecular profiling of the HGSC and the MLA were distinct and as expected for the different tumor types: HGSC was diffusely positive for WT-1, estrogen receptor, and p53 (mutant pattern), while negative for GATA-3 and TTF-1; MLA was positive for GATA-3 and TTF-1, while negative for WT1, estrogen receptor, and p53 (wild-type pattern); both tumors were diffusely positive for PAX-8. The HGSC revealed a TP53 c.659A>G (p.Y220C) mutation, and the MLA revealed a KRAS c.34G>T (p. G12C) mutation and a PIK3CA c.1034A>T (p.N345I) mutation. To the best of our knowledge, this is the first reported case of synchronous bilateral ovarian carcinomas with MLA and contralateral ovarian HGSC.

HER2 Status in Low-grade Serous Ovarian Tumors

Using immunohistochemistry, we examined a large cohort of 135 ovarian tumors, made up of 96 low-grade serous carcinomas (LGSCs) and 39 serous borderline tumors (micropapillary variant, mSBT), with the aim of exploring their HER2 status (overexpression). We followed with comprehensive genomic analyses on this sample set from our previous study, which revealed HER2 mutation in 5% (4/75) of LGSC and 10% (3/29) of mSBT. No cases were evaluated as HER2-positive, but 6 LGSCs and 1 mSBT were scored as HER2 1+, and 2 LGSCs and 1 mSBT showed the so-called HER2 “ultra-low” phenotype. This could be of clinical value as a potential therapeutical target concerning emerging therapeutic treatments (antibody conjugates). However, the clinical significance of this expression still needs to be established.

Association of Local and Distant Organ Metastases With MELF Pattern in Endometrial Cancer

Several types of myometrial invasion in endometrioid-type endometrial adenocarcinoma (EEC) have been identified: adenomyosis-like changes; adenoma malignum; broad front, single-cell/cell clusters; and the microcystic elongated and fragmented (MELF) pattern. This study aims to investigate the effect of the MELF pattern on recurrence type and survival rate among patients with EEC. We retrospectively reviewed the records of patients diagnosed with EEC over a 10-year period from January 2011 to January 2021. Among 108 patients with EEC, 54 had recurrence (study group), and 54 did not (control group). The MELF pattern was more common in the group with recurrence than in the group without recurrence (40.7% vs. 14.8%; P=0.002). The MELF pattern was observed in 60.0% of patients with local recurrence and 29.4% of patients with extrapelvic or distant organ metastases (P=0.027). Evaluation of 5-year disease-free survival (P=0.003) and overall survival (P=0.001) rates showed that MELF positivity was associated with decreased survival. Among patients with grade I-II EEC lacking uterine-localized myometrial invasion, the MELF pattern was less common in the nonrelapsed group than in the local relapse group (10.0% vs. 60.0%; P<0.001). The MELF pattern (odds ratio=19.4, 95% CI=1.2–31.2) was a significant independent negative predictor for local recurrence. The MELF pattern was more common in patients with recurrence, especially local recurrence. This finding suggests that the MELF pattern primarily impacts direct local invasion rather than hematogenous or lymphatic spread.

Prognostic Significance of “High” Tumor Budding and “High” Poorly Differentiated Clusters in Endometrial Carcinomas: Independent Predictors of Lymphovascular Space Invasion and Lymph Node Metastasis

Tumor budding (TB) and poorly differentiated clusters (PDCs) are well-established prognostic factors in various cancers. This study aimed to assess the independent prognostic role of these markers in endometrial carcinomas. Retrospective analysis of endometrial carcinoma resection specimens by examining traditional histologic prognostic parameters. TB and PDC were observed at 20× magnification in ten fields at the invasive front and categorized as present or absent. In addition, a count of ≥5 was stratified as “high.” Clinical and follow-up details were extracted from Gynecologic Oncology records. Sixty-five endometrial carcinomas were studied and were predominantly endometrioid (n=47, 72.3%). TB was identified in 52.3% of cases, with high TB observed in 38.5%. PDC was evident in 44.6%, with high PDC seen in 29.2%. Associations were significant between the presence of TB/high TB and higher tumor grade (P < 0.001), deep myometrial invasion (P = 0.006/P = 0.002), diffuse pattern of invasion (P = 0.007/P = 0.03), microcystic elongated and fragmented pattern (P < 0.001), lymphovascular space invasion, lymph node metastasis (P=<0.001) and International Federation of Gynecology and Obstetrics stage (P = 0.000/P = 0.002). PDC/high PDC showed similar associations, and, in addition, with nonendometrioid histologic type (P = 0.02) and tumor location in a lower uterine segment (high PDC, P = 0.009). After adjusting for other significant parameters, both high TB (P = 0.03) and high PDC (P = 0.031) emerged as independent prognostic parameters for lymphovascular space invasion or Lymph node metastasis. No recorded deaths or significant events occurred, precluding commentary on overall survival status. High TB and PDC are independent predictors of Lymph node metastasis in endometrial carcinomas. Their association with the microcystic elongated and fragmented pattern makes them histologic predictors of epithelial-mesenchymal transition. Their simple application underscores their potential as valuable additional prognostic indicators for endometrial carcinomas.

p53 Abnormal (Copy Number High) Endometrioid Endometrial Carcinoma Has a Prognosis Indistinguishable From Serous Carcinoma

Among the 4 molecular subgroups of endometrial carcinoma, the p53 abnormal (copy number high) subgroup has the worst prognosis; however, the histologic characteristics of this subgroup are not well established. Also, it is not well established whether low-grade tumors can belong to the p53 abnormal molecular subgroup and if so, what is the prognostic significance of the p53-mutated molecular subgroup in low-grade tumors. In the current study, we included 146 p53-mutated endometrial carcinomas and performed molecular subgrouping either based on a combination of immunohistochemical studies for p53 and MMR protein expression and POLE mutation testing (81 cases) or based on array-based and sequencing-based technologies (65 cases). We excluded cases that belonged to the POLE mutant or MSI molecular subgroups and only studied p53 abnormal (molecular subgroup) endometrial carcinomas (125 cases). In 71 cases, the molecular subgroup was determined by a combination of immunohistochemical studies and POLE mutation testing, and in 54 cases by array-based and sequencing-based methods. We reviewed 1 to 2 representative digital slides from each case and recorded the morphologic characteristics as well as clinical, treatment, and survival follow-up data. Overall, 47 cases were classified as endometrioid carcinoma, 55 serous carcinoma, and 23 other histotypes. Eight cases were FIGO 1, 21 were FIGO 2, and 91 were FIGO 3. A significant proportion of the cases (24.2%) were histologically classified as low-grade (FIGO 1 or 2) endometrioid carcinoma. There was no morphologic characteristic that showed prognostic implication. There was no significant difference in survival among different histotypes (P=0.60). There was no significant difference in survival among low-grade endometrioid (FIGO 1 or 2) versus high-grade (FIGO 3) tumors (P=0.98). Early-stage (stage I), low-grade tumors showed no significant survival advantage over early-stage, high-grade tumors (P=0.16) and this was more evident in FIGO 2 tumors. Although not statistically significant, the FIGO 2 tumors showed a trend toward worse survival than FIGO 3 tumors. Among the cases with available treatment data, more patients with early-stage high-grade tumors received adjuvant treatment, compared to patients with early-stage low-grade tumors, possibly explaining this trend (P=0.03). In conclusion, the findings of our study suggest that low-grade p53 abnormal endometrioid endometrial carcinomas (especially FIGO 2 tumors) have an aggressive course, with a prognosis similar to high-grade tumors. Furthermore, our study suggests that patients who had early-stage low-grade p53 abnormal disease might have been undertreated because of the “low-grade” histotype.

PRAME Expression in Endometrioid and Serous Endometrial Carcinoma: A Potential Immunotherapeutic Target and Possible Diagnostic Pitfall

Preferentially expressed antigen in melanoma (PRAME) is a cancer testes antigen initially employed as a diagnostic marker for melanoma. Although negative in most normal tissues, its expression has been reported in benign endometrial glands. Additionally, PRAME expression has been identified in a growing list of solid and hematologic malignancies and is of interest as a predictive biomarker, as cancer vaccination strategies and adoptive T-cell transfer targeting this molecule are under clinical investigation; additionally, PRAME may identify candidates for retinoid therapy. However, expression of PRAME has not been well-studied in endometrial cancers. We herein evaluate PRAME expression in endometrial carcinomas to better characterize its limitations as a diagnostic melanoma marker as well as its potential as a predictive biomarker in endometrial carcinomas. PRAME expression was evaluated in 256 endometrioid (n=235) and serous (n=21) endometrial carcinomas via tissue microarray. In all, 89% (227/256) demonstrated some degree of nuclear PRAME expression, including 88% (207/235) of endometrioid carcinomas and 95% (20/21) of serous carcinomas. Diffuse (>50%) expression was observed in 70% (179/256) of all cases, including 69% (163/235) of endometrioid carcinomas and 76% (16/21) of serous carcinomas. There was no association between degree of expression and grade, mismatch repair protein status, or stage. The widespread expression of PRAME in endometrial carcinomas suggests this marker should not be interpreted as specific for melanoma in this context. However PRAME may have utility as a predictive biomarker in endometrial cancer, and expansion of testing of PRAME-based therapies to endometrioid and serous endometrial carcinomas may lead to new therapeutic options for these endometrial cancer subtypes.

Synchronous Endometrial and Ovarian Endometrioid Carcinoma With MUTYH Germline Mutation: A Case Report With Genetic Analysis

Synchronous endometrial and ovarian endometrioid carcinoma, which simultaneously involves the endometrium and ovary, is a relatively rare entity among gynecological cancers. Precise diagnosis and risk stratification are crucial for disease management. We present a unique case of a 40-year-old woman diagnosed with synchronous endometrial and ovarian endometrioid carcinoma carrying a monoallelic pathogenic MUTYH germline variant. Despite the histological morphology of the right ovarian tumor exhibiting some differences compared to the uterine tumor, we identified three identical somatic mutations shared between the uterine tumor and right ovarian tumor, along with four additional mutations exclusive to the uterine tumor, through the utilization of massively parallel sequencing of a 196-gene panel. These findings enabled us to elucidate the clonal relatedness and potential clonal evolution of the tumor across the two anatomical sites. Furthermore, in accordance with the 2023 FIGO staging system, the patient was diagnosed with Stage IIIB2 uterine cancer, and consequently, adjuvant radiation and chemotherapy were administered after surgery. She is being followed periodically and is normal 15 months after surgery. To the best of our knowledge, this study presents the first case of a patient with synchronous endometrial and ovarian endometrioid carcinoma harboring a monoallelic pathogenic MUTYH germline variant.

Molecular Surrogate Subtypes of Ovarian and Peritoneal Low-grade Serous Carcinoma

Low-grade serous carcinoma (LGSC) is an uncommon histotype of ovarian carcinoma, accounting for ~3% of cases. There is evidence that survival of peritoneal LGSC (pLGSC) is longer than that of ovarian LGSC (oLGSC). Key molecular alterations of LGSC have been established, including loss of CDKN2A and PR expression, MAPK pathway alterations, and loss of USP9X expression. We hypothesized that LGSC could be subclassified into clinically applicable molecular subtypes by a few surrogate tests similar to endometrioid carcinomas using a hierarchical decision tree based on the strength of the prognostic associations of the individual alterations. Our study included 71 LGSCs. Immunohistochemistry for CDKN2A, ER, PR, NF1, and USP9X and sequencing for KRAS, NRAS, and BRAF were performed. Our data showed the co-occurrence of key molecular alterations, and despite suggestive trends, hierarchical molecular subtyping did not provide significantly different stratification of patients according to survival in this cohort. We confirmed that patients diagnosed with pLGSC have a longer survival than high-stage oLGSC, with the intriguing observation that normal CDKN2A and PR status were associated with excellent survival in pLGSC. Therefore, CDKN2A and PR status might aid in the classification of indeterminate implants, where abnormal findings favor pLGSC over noninvasive implants. Molecular subtypes should be further evaluated in larger cohorts for their prognostic and potentially predictive value.

The Prognostic Value of Tumor Cell Clusters in the Fallopian Tube Lumen in Stage I Endometrioid Carcinoma

The aim of this study was to investigate the pathologic prognostic factors such as tumor cell clusters (TCCs) in the fallopian tube lumen, myometrial invasion patterns, and positive peritoneal cytology (PPC) in women with Stage I endometrial endometrioid carcinoma (EEC). From 2009 to 2020, consecutive patients with Stage I EEC who underwent hysterectomy and bilateral salpingectomy were included. The primary outcome was the recurrence-free survival (RFS) rate, and the clinicopathological factors affecting RFS were analyzed. A total of 765 patients were enrolled. Seventeen patients (2.2%) had TCC in the fallopian tube lumen, and 58 patients showed a microcystic elongated and fragmented pattern (7.6%). PPC was found in 19 patients (2.5%). The median follow-up period was 61.0 months (range: 2.0–149.7). The majority (88.6%) of patients had Stage IA EEC. The 5-year RFS and overall survival rates were 97.5% and 98.5%, respectively. In multivariate analysis for RFS, the significant prognostic factors were lymphovascular invasion (hazard ratio = 4.604; 95% CI: 1.387–15.288; P = 0.013) and grade (grade 2; hazard ratio = 4.949; 95% CI: 1.035–23.654; P = 0.045, and grade 3; hazard ratio = 5.469; 95% CI: 1.435–20.848; P = 0.013). Other pathologic factors including TCC in the fallopian tube lumen, myometrial invasion patterns, PPC, and hormonal status had no prognostic significance. TCC in the fallopian tube lumen, myometrial invasion pattern, PPC, and estrogen and progesterone receptor positivity were not significant prognostic factors in Stage I EEC. In contrast, lymphovascular invasion and grade were significant prognostic factors.

Folate Receptor Immunohistochemical Staining and Gynecologic Tumors: Initial Experience With 216 Cases

Folate receptor alpha has been shown to have possible mechanisms of tumorigenesis in malignancies, becoming a potential target for therapy. Mirvetuximab soravtansine is an antifolate receptor alpha monoclonal antibody, with an approved FOLR1-2.1 immunohistochemical biomarker. After IRB approval, a retrospective review of gynecologic pathology cases was performed to identify cases in which FOLR1 immunohistochemistry (IHC) was performed at our institution over a period of 9 months as part of clinical care for therapy eligibility. Clinical data collected included patients’ age, tumor histotype, tumor grade, primary tumor site, FIGO stage, dates of recurrence/progression, and use of mirvetuximab therapy. FOLR1 IHC data were recorded, including the date specimen obtained, date IHC was performed, site tested, case type, percentage tumor staining, and intensity. Cases were deemed positive or negative according to current recommendations (75%, 2−3+intensity). Two hundred sixteen cases were identified. Patient ages ranged from 25 to 83 years old (median: 59 yr). Staining intensity was reported as 0 in 15 (6.9%) cases, weak (1+) in 8 (3.7%), moderate (2+) in 27 (12.5%), strong (3+) in 27 (12.5%), weak-to-moderate (1−2+) in 15 (6.9%), and moderate-to-strong (2−3+) in 99 (45.8%); intensity was not provided in 25 (11.6%). Percentage of tumor staining ranged from 0 to 100, with a median of 60. The IHC was overall deemed positive in 98 (45.4%) cases and negative in 118 (54.6%). By histotype, 5 of 17 (29.4%) low-grade serous carcinomas, 88 of 162 (54.3%) high-grade serous carcinomas, 3 of 5 (60%) of carcinosarcomas, and 2 of 6 (33.3%) of mixed carcinomas were positive. No case of clear cell CA, endometrioid CA, Mullerian CA NOS, serous borderline, mucinous CA, or granulosa cell tumor was positive. The primary site of disease was tubo-ovarian in 192 (88.9%) cases, peritoneal in 8 (3.7%) cases, uterine in 3 (1.4%) cases, and unknown in 13 (6%) cases. By site on which immunohistochemical stain was performed: primary site positive in 53 of 96 (55.2%) cases, metastatic site at time of diagnosis/debulking positive in 23 of 41 (52.1%) cases, and metastatic/recurrent cases positive in 22 of 79 (27.8%) cases. There was a statistically significant correlation when comparing the positivity rates between these sites (P = 0.0004). Survival data were examined with high-grade serous carcinoma, with no statistically significant difference between positive and negative cases in overall survival (P = 0.622) or progression-free survival (P = 0.711). Biopsy specimens were positive in 17 (25%) cases, while negative in 51 (75%), whereas resection specimens were positive in 81 (54.7%) and negative in 67 (45.3%), a statistically significant difference (P < 0.0001). Cases that were <19 months old had 38 (36.2%) positive and 67 (63.8%) negative, compared with cases ≥19 months old that had 60 (54.1%) positive and 51 (45.9%) negative, a statistically significant difference (P = 0.0084). Significant differences in FOLR1 staining were noted between histotypes, age of the specimen, type of case tested, and site of disease tested. Further testing is needed to help determine the best tissue to be utilized for this new biomarker.

Targetable ERBB2/HER2 Mutations in Gynecologic Malignancies: Clinicopathological, Immunohistochemical, and Molecular Correlations

Targeted anti-HER2 therapy has been recently added to the standard treatment recommendations in endometrial serous carcinoma. Current eligibility requires testing for HER2 overexpression and/or gene amplification by immunohistochemistry and by fluorescence in situ hybridization. However, clinical trials have also demonstrated the efficacy of anti-HER2 drugs against activating ERBB2/HER2 mutations in a variety of solid tumor types, and fam-trastuzumab deruxtecan is now approved by the US Food and Drug Administration for HER2-mutant non-small cell lung cancer. This study aimed at evaluating the detailed clinical, histomorphological, immunohistochemical, and molecular characteristics of gynecologic malignancies with ERBB2/HER2 mutations. We identified 16 tumors with 19 ERBB2/HER2 mutations in our departmental archives: 11 endometrial primaries, 2 endocervical adenocarcinomas, 1 ovarian mucinous adenocarcinoma, 1 tubo-ovarian undifferentiated carcinoma, and 1 high-grade endometrioid adenocarcinoma of Mullerian origin. ERBB2/HER2 mutations most often involved the tyrosine kinase domain (52.6%), and the most frequent specific mutation was R678Q (31.6%), involving the juxtamembrane domain. More than half (54.5%) of endometrial carcinomas and half of all tumors were MMR-deficient, resulting from MSH6 loss in all but 2 tumors. None of the tumors (0%) were POLE-mutated, while 18.8% were TP53-mutated. HER2 IHC was negative (score 0 or 1+) in 12 tumors (67%) and equivocal (score 2+) in 4 tumors (33%), whereas none of the tumors were scored as HER2 3+. Score 2+ was associated with R678Q, L755S, I767M mutations, and ERBB2/HER2 rearrangement with a breakpoint in exon 23. Concurrent ERBB2/HER2 amplification was identified in 2 endometrial carcinomas, with HER2/CEP17 ratios of 3.1 and 3.5. We also queried the cBioportal database, which revealed 70 ERBB2/HER2-mutant gynecologic tumors with a total of 77 ERBB2/HER2 mutations, most often involving the active site of the tyrosine kinase domain (n=36; 46.8%), and the most common specific mutation was S310F (n=20; 26%), located in the extracellular domain. Our results provide important details regarding the clinicopathological and molecular associations of potentially actionable ERBB2/HER2 mutations in endometrial carcinoma and other gynecological cancer types and contribute to addressing clinical treatment needs and improving pathology testing recommendations in the future.

WT1 Positive Ovarian Endometrioid Tumors: Observations From Consult Cases and Strategies for Distinguishing From Serous Neoplasms

Ovarian endometrioid carcinoma, more than any other type of ovarian epithelial malignancy, demonstrates a varied morphology which can cause problems in diagnosis. In tubo-ovarian tumor pathology, WT1 is a commonly used marker as it is consistently expressed in low-grade and high-grade serous carcinomas and is often considered a specific marker of a serous phenotype. However, ovarian endometrioid neoplasms may also express WT1 which may contribute to misdiagnosis. We report our experience with 23 ovarian endometrioid neoplasms (4 borderline tumors, 19 carcinomas), mainly received in consultation, which were WT1 positive (diffuse in 11 cases) which often contributed to misdiagnosis. Endometriosis was identified in the same ovary in 6 cases and squamous elements in 7. We describe strategies for distinguishing such neoplasms, which may exhibit morphologic overlap with serous tumors, from low-grade and high-grade serous carcinomas and stress that a diagnosis of HGSC is unlikely with two grossly and histologically normal fallopian tubes. We also stress that a panel of markers should always be used rather than relying on a single marker and that when the morphology is classical of an endometrioid carcinoma, diagnostic immunohistochemistry is not needed given the potential for confusion in cases showing “aberrant” staining. We also discuss the phenomenon of “aberrant” immunohistochemical staining in endometrioid carcinomas which appears more common than in other ovarian carcinomas.

FOXA1 Expression by Immunohistochemistry in Carcinosarcomas of the Endometrium and Ovary/Fallopian Tube

FOXA1, a transcription factor essential for the binding of other transcription factors on chromatin, is associated with hormone receptor-associated cancers, such as breast and endometrial cancer. It is also considered an antagonist of epithelial-to-mesenchymal transition (EMT). In endometrial cancer, FOXA1 is considered a tumor suppressor; in carcinosarcoma, one of the most aggressive and rare subtypes of endometrial cancer, thought to be derived through an EMT mechanism, FOXA1 has not been studied. Thus, the aim of this study was to investigate the possible expression of FOXA1 in carcinosarcomas, and its correlation with clinicopathologic factors. This was a retrospective study of 31 patients diagnosed with carcinosarcomas of the uterus or the adnexa. Histologic and clinical factors were correlated with the immunohistochemical expression of FOXA1. FOXA1 was expressed by 38.7% of the carcinomatous components and 16.1% of the sarcomatous components. FOXA1-positive sarcomatous components were seen only with positive carcinomatous components (P=0.004). FOXA1 expression was not associated with age, primary tumor site, stage, metastases, overall survival, or tumor relapse. FOXA1 expression in the carcinomatous component was associated with an absence of lymphovascular invasion or the presence of heterologous components. FOXA1 expression in the sarcomatous component was associated with rhabdomyosarcoma, rather than the chondrosarcoma heterologous component. Carcinosarcomas harbor FOXA1 expression, although it is in their carcinomatous rather than sarcomatous components, suggesting a possible role of FOXA1 in the EMT of carcinosarcomas. FOXA1 shows no prognostic significance in this tumor group.

Divergent Malignant Melanocytic Differentiation in Ovarian Endometrioid Adenocarcinoma With Aberrant β-Catenin Expression: A Case Expanding the Histologic Spectrum of β-Catenin Activated Gynecologic Neoplasia

Divergent differentiation in gynecologic carcinomas encompasses a broad range of lineages, including mesenchymal, germ cell, high-grade neuroendocrine, neuroectodermal, and cutaneous adnexal differentiation. Here we present a case of ovarian endometrioid adenocarcinoma with divergent malignant melanocytic differentiation (MMeD). The background ovarian endometrioid adenocarcinoma showed focally aberrant β-catenin expression and histologic patterns associated with β-catenin activation, including spindled elements and corded and hyalinized foci. The areas with MMeD had both spindled and epithelioid morphology, diffusely aberrant β-catenin expression, expression of melanocytic markers (an HMB45/Mart-1 cocktail, MITF, and S100), and no staining for myogenic markers (SMA and desmin) or epithelial markers (cytokeratins and E-cadherin). INI1, BRG1, PMS2, and MSH6 were retained, and p53 showed a wild-type expression pattern. No areas with definitive carcinosarcomatous differentiation were identified despite extensive sampling. While a single case of gynecologic carcinosarcoma with a serous epithelial component and a small focus on malignant melanoma has been reported in the English literature, the current case represents what is, to the best of our knowledge, the first case of MMeD arising in the context of a β-catenin activated endometrioid adenocarcinoma. Pathogenetic and differential diagnostic considerations are discussed.

High-grade Serous Carcinoma Occurring in a Serous Cystadenoma on the Background of a Serous Tubal Intraepithelial Carcinoma (STIC)-like Lesion: A Case Report With Literature Review

At present, the prevailing concept is that high-grade serous carcinoma (HGSC) arises from the fallopian tubes (FTs). We report an HGSC case occurring in a serous ovarian cyst against the background of a serous tubal intraepithelial carcinoma (STIC)-like lesion. We also provide a literature review that contains references to clinical cases of the occurrence of STIC-like lesions in the ovary and phylogenetic studies that do not always reveal obvious bonds between early dysplastic serous lesions and HGSC. The article discusses cases of association between HGSCs of serous borderline tumors (SBTs) and low-grade serous carcinomas (LGSCs) in the context of their possible histogenetic relationship. We propose a concept in which high-grade serous carcinogenesis, represented by the p53-signature–STIC–HGSC continuity, occurs in the serous epithelium of both the FT and other locations.

Endometrial Cancer in a Family With RAD51D Gene Mutation

RAD51 complex plays an important role in homologous recombination deficiency and germline mutations have a well-documented association with breast and tubo-ovarian carcinoma, as well as serous-type endometrial carcinoma. We report a family of French Canadian ancestry with a germline mutation in RAD51D and two sisters presenting with endometrial carcinoma, endometrioid-type. The risk factors for endometrial adenocarcinoma, endometrioid-type are discussed in the context of the RAD51-associated carcinomas described to date.

Comparison of PD-L1, VISTA, LAG-3, and GAL-3 Expressions and Their Relationships to Mismatch Repair Protein and p53 Expression in 529 Cases of Endometrial Carcinoma

The aim of this study is to evaluate the expressions of programmed death-ligand 1 (PD-L1), V-domain Ig suppressor of T-cell activation (VISTA), lymphocyte activation gene-3 (LAG-3), and galectin-3 (GAL-3), in mismatch repair-deficient (MMRd)/MMR-proficient and abnormal p53 expressing endometrial carcinomas and their relationship with clinical-histopathological features. Patients who underwent surgery for endometrial carcinoma between January 2008 and December 2018 were included in the study. Immunohistochemical analysis of MLH1, PMS2, MSH2, MSH6, p53, PD-L1, VISTA, LAG-3, and GAL-3 was performed on the tissue samples of microarray. A total of 529 patients were included. MMRd and p53-mutant tumors accounted for 31.5% and 11.5% of cases, respectively. PD-L1 and LAG-3 expressions in the MMRd and p53-mutant groups were higher than in the MMR-proficient group (P < 0.001). GAL-3 expression in the MMR-proficient group was statistically higher than in the MMRd and p53-mutant groups (P < 0.001). Mean age, grade, International Federation of Gynecology and Obstetrics stage, lymphovascular invasion, and lymph node metastasis were significantly higher in the p53-mutant group (P < 0.001). In the group with PD-L1 expression, nonendometrioid histologic type, tumor grade, and lymphovascular invasion were significantly higher (P < 0.001). Tumor grade, lymphovascular invasion, lymph node metastasis, and microcystic, elongated and fragmented pattern of invasion were significantly higher in the group with high VISTA expression (P < 0.05). Tumor grade was significantly higher in the group with LAG-3 expression (P < 0.001). Immunohistochemically determined subgroups and PD-L1, VISTA, LAG-3, and GAL-3 expression levels may be useful indicators of molecular features, and clinical outcomes also may have important implications for the development of targeted therapies in endometrial carcinoma.

Survey on Reporting of Endometrial Biopsies From Women on Progestogen Therapy for Endometrial Atypical Hyperplasia/Endometrioid Carcinoma

Histologic assessment of response to progestogen therapy is a cornerstone of nonsurgical management of atypical hyperplasia/low-grade endometrioid carcinoma. Pathologists are required to assess whether there is ongoing preneoplastic or neoplastic change in the biopsies (often multiple) taken during therapy. There have been few studies documenting the specific histologic changes induced by therapeutic progestogens and currently there are no guidelines on terminology used in this scenario. Given the need for uniformity in reporting and the lack of guidance in the current literature, we initiated an online survey (including questions, categories of reporting, and scanned slides for assessment) which was sent to all members of British Association of Gynaecological Pathologists (BAGP) and the International Society of Gynecological Pathologists (ISGyP) with the aim to assess the variability among pathologists in reporting these specimens and to come up with a consensus-based terminology for reporting of endometrial biopsies from women on progestogen therapy for endometrial atypical hyperplasia/endometrioid carcinoma. In total, 95 pathologists participated in this survey. This manuscript elaborates on the results of the survey with recommendations aimed at promoting uniform terminology in reporting these biopsies.

Metastatic Hepatocellular Carcinoma Represents an Important but Rare Pitfall in the Diagnostic Evaluation of ER Negative Ovarian Malignancy: A Case Report

Metastatic hepatocellular carcinoma (HCC) to the ovary is a rare and challenging histopathological diagnosis in the absence of the relevant clinical history. The differential diagnoses of a hepatoid tumor in the ovary are extensive, and correct diagnosis requires well-considered clinical-pathologic correlation. Familiarity with the diverse architectural patterns and immunophenotype of HCC is essential; however, even in the setting of known hepatic disease, a well-developed pseudoglandular pattern may be a convincing morphologic mimic of a primary surface epithelial ovarian malignancy. We describe a diagnostically challenging case of a 50-year-old woman with metastatic HCC exhibiting a prominent pseudoglandular pattern mimicking primary endometrioid adenocarcinoma, and an approach to overcome this important pitfall.

Ovarian Endometrioid Adenocarcinomas With Infiltrative “Adenofibroma-like” Morphology and Aberrant ß-catenin Expression: Tumors That Coexpress CDX2 and LEF1 With Frequent Neuroendocrine Marker Expression, Diminished/Lost PAX8 and Possible Association With Endometrioid Type II Stem Cell Outgrowths in the Fallopian Tube

Synchronous Endometrial and Ovarian Carcinomas: Pathologic and Molecular Analysis Highlights the Monoclonal Origin of the Lesions

The diagnosis of synchronous carcinomas, involving both the endometrium and ovaries, is not a rare finding in gynecologic pathology and represents a challenge with implications on tumor staging and therapeutic decision-making. A mono-institutional series of 11 metastatic and 6 paired synchronous endometrial and ovarian carcinomas were reviewed by 2 expert pathologists based on previously published histopathologic criteria. The series was investigated for DNA mismatch repair proteins, p53, and POLE status and was subject to DNA-based next-generation sequencing targeting 67 cancer-related genes. Out of 17 pairs, 16 featured the same histotype (10 endometrioid, 4 serous high-grade, and 2 clear cells). By using WHO 2020 criteria, 11 couples of tumors were confirmed as metastatic and 6 couples were confirmed as independent. Based on next-generation sequencing analysis, 16 of 17 cases (11 metastatic and 5 independent) of our series showed evidence of a clonal relationship between endometrial and ovarian carcinomas. In metastatic cases, the adverse outcome was associated with nonendometrioid/high-grade endometrioid histotype and with the p53-abnormal molecular subtype. Four cases originally fulfilling clinicopathological criteria of independent endometrial and ovarian carcinomas were clonally related, low-grade endometrioid histotype and POLE-mut, mismatch repair deficient, and no specific molecular profile molecular subtypes; no adverse event was recorded in this group. In summary, the molecular characterization of synchronous gynecologic carcinomas confirms their clonal origin in most cases. However, the results of our study point out that the clinical behavior of these tumors seems to be determined by the presence of high-risk WHO 2020 histologic criteria and molecular features (i.e. p53-abnormal), rather than the monoclonal origin.

HER2-low and Overexpression in Mucinous Ovarian Cancer: Analysis of ASCO/CAP and ToGA Immunohistochemical Scoring

Mucinous ovarian carcinoma is an uncommon malignancy characterized by resistance to chemotherapy and poor survival in the metastatic setting. HER2 amplification is a frequent late event in carcinogenesis, yet the incidence of HER2-low in mucinous ovarian carcinoma is unknown. Further, the optimal method for determining overexpression in these tumors is not established. We sought to assess the ASCO/CAP and ToGA trial scoring methods for HER2 IHC with correlation to FISH, p53, and mismatch repair protein status and to determine the incidence of HER2-low in mucinous ovarian carcinoma. A total of 29 tumors from 23 patients were included. Immunohistochemistry for HER2, p53, MLH1, PMS2, MSH2, and MSH6 was performed. Scoring was performed according to the ASCO/CAP and ToGA trial criteria. HER2 FISH was performed and scored according to the ASCO/CAP criteria. The proportion of HER2-low, defined as 1+ or 2+ staining with negative FISH, was determined. Using ASCO/CAP, 26% demonstrated 3+ while 35% demonstrated 2+ staining. Using ToGA, 30% demonstrated 3+ while 57% demonstrated 2+ staining. By FISH, 26% were positive for HER2 amplification. Both systems captured all FISH-positive cases; the use of ASCO/CAP resulted in fewer equivocal and false-positive cases. Among HER2-negative cases, 88% were HER2-low. Aberrant p53 expression was detected in 55% of cases; mismatch repair deficiency was not identified in any cases. ASCO/CAP guidelines are accurate and resource-effective in determining HER2 overexpression in mucinous ovarian carcinoma. HER2-low is common in these tumors; further studies to determine the role of HER2-targeted therapy including antibody-drug conjugates are indicated.

Novel FOXL2 Mutation in an Ovarian Adult Granulosa Cell Tumor: Report of a Case With Diagnostic and Clinicopathologic Implications

Adult granulosa cell tumor, the most common malignant ovarian sex cord–stromal tumor, harbors the characteristic mutation c.402C>G (p.C134W) in the FOXL2 gene in ~90% to 95% of cases. To date, no other variants of FOXL2 mutations have been identified in these tumors. Here we report the first case of an adult granulosa cell tumor with a novel FOXL2 point mutation c.398C>T (p.A133V) presenting in a 64-year-old postmenopausal woman. The patient underwent total hysterectomy and bilateral salpingo-oophorectomy for atypical endometrial hyperplasia and gross examination revealed an incidental 3.2 cm right ovarian mass with a solid, bright yellow, homogeneous cut surface. Microscopically, ~30% of the tumor showed a nested growth pattern composed of uniform tumor cells with oval nuclei and a moderate amount of pale cytoplasm, while the remaining areas consisted of a bland storiform fibromatous stroma. Reticulin stain demonstrated loss of the individual pericellular network within the nested areas, while the pericellular staining pattern was retained in the background stromal component. FOXL2 sequencing analysis was performed in both components and revealed a c.398C>T (p.A133V) mutation in the nested component, whereas wild-type FOXL2 sequence was identified in the fibromatous stroma. Sections from the uterus showed a low-grade endometrioid endometrial adenocarcinoma with superficial myometrial invasion. The patient underwent adjuvant vaginal cuff brachytherapy for the endometrial carcinoma and is alive and well at 8 months follow-up. This case illustrates that new FOXL2 mutations may be detected in ovarian sex cord–stromal tumors with increasing use of routine molecular testing, adding to the complexity of the pathologic diagnosis. In the right morphologic and clinical context, a FOXL2 mutation—even if it is different from the dominant hotspot mutation c.402C>G (p.C134W)—can support the diagnosis of adult granulosa cell tumor.

Endometrioid Adenocarcinoma With “Burrowing” Invasion of the Cervix Represents a Separate Primary From the Concurrent Uterine Corpus Endometrial Endometrioid Adenocarcinoma: Histology, Immunohistochemistry, and Next-generation Sequencing Study of a Single Case

A small subset of endometrial endometrioid adenocarcinoma cases first reported in 2003, showed a distinct cervical component with a so-called “burrowing” invasion pattern. Initially, the cervical component was regarded as cervical involvement by the endometrial adenocarcinoma. However, a 2010 study argued that these cases actually might represent separate primary endometrial and cervical endometrioid adenocarcinomas. However, additional data on this topic are scarce. Here, we report a case of endometrioid adenocarcinoma with a “burrowing” cervical invasion that is morphologically distinct from the patient’s endometrial endometrioid adenocarcinoma. By comparing the morphology, immunophenotype, and genetic profile obtained by next-generation sequencing, we demonstrated that the cervical and endometrial tumors were of 2 separate primaries. Our report adds additional data to this unique phenomenon, and will hopefully help to reignite interest in investigating this controversial topic.

Synchronous Bilateral Ovarian Mesonephric-like Adenocarcinomas with Separate Origins from High-Grade Mullerian Adenosarcoma and Endometriosis: Report of a Rare Case

Mesonephric-like adenocarcinoma (MLA) of the ovary is a recently recognized, rare malignancy with aggressive clinical behavior, and is thought to originate from Mullerian epithelium with mesonephric transdifferentiation. Emerging evidence suggests that MLA may be classified as an endometriosis-associated neoplasm. The presence of a sarcomatous component within MLA is extremely rare, with common differential diagnoses including the spindle cell component of MLA, carcinosarcoma, as well as mixed Mullerian adenocarcinoma and adenosarcoma. Herein, we report a 58-year-old Chinese woman with bilateral ovarian solid-cystic masses. The left ovarian mass comprised a biphasic tumor with a predominantly high-grade sarcomatous component displaying heterologous mesenchymal differentiation, including liposarcoma, rhabdomyosarcoma and chondrosarcoma-like areas, with a null-type p53 expression. The epithelial component ranged from a bland appearance in areas diagnostic of adenosarcoma to a clearly invasive carcinoma, both with mesonephric-like phenotype, being negative for estrogen receptor, progesterone receptor, and Wilms' tumor 1, variably positive for paired box gene 8, GATA binding protein 3, and thyroid transcription factor 1, with a wild-type p53 expression. The differing p53 expression between the epithelial and sarcomatous elements mitigated against a diagnosis of carcinosarcoma. The right ovarian mass showed endometriosis with focal direct evidence of the development of malignancy within a benign endometriotic cyst, exhibiting the identical immunoprofile of MLA but originating as another malignancy. To the best of our knowledge, this case represents the first reported case of synchronous bilateral ovarian MLAs with separate origins, from high-grade Mullerian adenosarcoma and endometriosis respectively, which broadens the morphologic spectrum of MLA and provides further evidence supporting the Mullerian origin theory.

Predicting Progestin Therapy Response With PTEN, PAX2, and β-Catenin in Patients With Endometrioid Precancer

This study investigates the predictive value of biomarkers PTEN, PAX2, and β-catenin for therapeutic outcomes in patients with atypical endometrial hyperplasia or endometrioid intraepithelial neoplasia undergoing progestin therapy. In a retrospective study of 128 patients, we analyzed a total of 351 endometrial biopsy samples and categorized outcomes into responders (absence of residual disease) and nonresponders (presence of residual disease). We found aberrant biomarker expression in pretreatment cases: 48% for PTEN, 65% for PAX2, and 36% for β-catenin. Approximately 77.3% of patients responded to progestin treatment, with nonresponders showing significantly higher initial PTEN loss (75.86% vs 39.79%, P < 0.001). Nonresponders also demonstrated significant PTEN loss (53.33% vs 20.55%, P < 0.001), PAX2 loss (57.33% vs 41.22%, P < 0.05), and β-catenin nuclear staining (53.45% vs 27.91%, P < 0.01) in follow-up samples. In addition, nonresponders exhibited lower recovery of intact PTEN and PAX2, along with higher β-catenin aberrancy in cases initially showing normal β-catenin levels. We conclude that persistent aberrant PTEN and PAX2 expression, coupled with emerging aberrant β-catenin in follow-ups, indicates a greater likelihood of treatment failure. Conversely, the absence of these aberrations suggests successful progestin therapy. Our findings highlight the utility of this 3-marker panel in assessing residual disease status and predicting progestin treatment outcomes, thus offering critical insights for patient management.

Napsin A Immunoreactivity in “Hobnail” Epithelium in Benign Endometrial and Endocervical Polyps

Endometrial and endocervical polyps not uncommonly exhibit focal benign “hobnail” change/metaplasia within the glandular epithelium, sometimes in association with inflammation or infarction. In most cases, this is readily recognized as benign but occasionally, especially in endometrial polyps, this change prompts consideration of a premalignant or malignant lesion, including early serous or clear cell carcinoma. Herein we highlight the previously unreported phenomenon of positive staining of this hobnail epithelium with Napsin A which has the potential to exacerbate concern for clear cell carcinoma. Endometrial (n = 22) and endocervical (n = 17) polyps showing hobnail change were stained with Napsin A. Six cases were positive (4 of 22 endometrial and 2 of 17 endocervical polyps). In all cases, Napsin A positivity was confined to the hobnail epithelium. The hobnail epithelium was positive with estrogen receptor and hepatocyte nuclear factor 1- beta and exhibited wild-type immunoreactivity with p53 in all cases where these markers were performed. In addition, in 2 of 3 uterine adenosarcomas with focal hobnail change the epithelium was Napsin A positive. Pathologists should be aware that Napsin A may be expressed in benign/reactive hobnail epithelium in endometrial and endocervical polyps and should not consider positivity with this marker as a diagnostic of clear cell carcinoma.

PReferentially Expressed Antigen in MElanoma Expression in Uterine and Ovarian Carcinosarcomas

Carcinosarcoma (CS) is an aggressive form of gynecologic malignancy that accounts for ~5% of carcinomas in the endometrium and ovaries. There has been no significant improvement in survival over the last decades despite additional treatment options. PReferentially Expressed Antigen in MElanoma (PRAME) is an immunotherapy target used for the treatment of several solid tumors. We explored the PRAME protein expression levels in ovarian and uterine CS (n = 29). The expression levels were recorded by H-score (percentage of positively stained cells multiplied by staining intensity) in carcinomatous and sarcomatous components separately and compared by paired t-test. The marker expression levels of ovarian and uterine CS were tested against each other in the CS group. Sarcoma-predominant samples (>50% of the sampled tissue) were compared with samples without predominant sarcomatous components by a 2-sample pooled t-test. In addition, high-grade carcinomatous components of CS samples were tested against low-grade endometrioid carcinoma (International Federation of Gynecology and Obstetrics grades 1 and 2; n = 13), and sarcomatous components against uterine leiomyosarcoma (n = 14). There was no significant difference between any subgroups except for sarcomatous elements of CS and leiomyosarcoma (P < 0.001). A weak positive correlation was found between H-scores of carcinomatous and sarcomatous components (P = 0.062, r = 0.36). In the ovarian CS group, there was a moderate inverse correlation between age and the mean H-score of the carcinomatous component (r = −0.683, P = 0.02). Our results further support PRAME overexpression in gynecologic cancers, including CS with similar expression levels in epithelial and mesenchymal components. PRAME might have a role in epithelial-mesenchymal transition in this group of cancers.

A Novel EPC1::KDM2B Fusion in High-grade Endometrial Stromal Sarcoma

The spectrum of endometrial stromal sarcoma (ESS) has expanded substantially since the publication of the most recent World Health Organisation (WHO) Classification of Female Genital Tumours and the advent of widely available genomic testing. We describe a uterine mesenchymal tumor harboring a novel EPC1::KDM2B fusion, best classified within the umbrella of high-grade endometrial stromal sarcoma (HGESS). This tumor was composed of a uniform population of spindled cells with some myxoid stroma, a mitotic rate of up to 21/10 high-power fields, and a largely pushing margin with focal vascular invasion. Immunohistochemistry showed strong and diffuse cyclin D1 positivity while CD10, WT1, DOG1, CD117, CD34, CD99, S100, MelanA, SMA, desmin, and h-caldesmon were negative. The tumor was confined to the uterus and no recurrence has been detected thus far, albeit with a short follow-up interval of 9 mo.

Endometrial Carcinoma of Gastrointestinal-type (EMCG): Incidence, Molecular Features, and Distinction From Other Endometrial Cancers With Gastrointestinal Marker Immunoexpression

Endometrial carcinoma of gastrointestinal-type (EMCG) is an aggressive endometrial cancer characterized by gastric and/or intestinal-type mucinous morphology, absent/minimal estrogen receptor expression, and at least focal gastrointestinal marker immunoexpression. We herein present a clinicopathologic characterization of 4 EMCG: 2 were prospectively diagnosed, and 2 found on retrospective screening of 274 endometrial carcinomas performed to identify undetected EMCG and characterize gastrointestinal marker expression within our endometrial carcinoma population. All 4 EMCG expressed CDX2 and were negative for SATB2; CK20 was diffuse in one, focal in another, and absent in 2. None showed strong membranous Claudin-18. One was MMR-deficient; 2 had PTEN loss. Sequencing revealed a variety of molecular events, including pathogenic/likely pathogenic variants KRAS, PIK3CA, POLE, PTEN, SMARCA4 , and TP53 . Thirty-six percent of retrospectively screened endometrial carcinomas expressed at least one gastrointestinal marker; however, the majority had strong ER co-expression, precluding EMCG classification. Other than the 2 cases of true EMCG identified on screening, only one screen-positive tumor had convincing gastrointestinal-type morphology in concert with ER negativity; this case showed SALL4 and AFP expression consistent with a somatically derived yolk sac tumor. These data provide an expanded understanding of the molecular underpinnings of EMCG—including the first description of a SMARCA4 frameshift variant in this entity—and demonstrate that while gastrointestinal marker immunoexpression is relatively common among endometrial carcinomas, strictly defined EMCG remains rare (<1%). As awareness of this entity grows, pathologists should take care not to over-interpret gastrointestinal marker expression as stand-alone evidence of an EMCG diagnosis.

Uterine Mesenchymal Neoplasm With BRD8::PHF1 Fusion: Low-grade Endometrial Stromal Sarcoma or Uterine Ossifying Fibromyxoid Tumor?

We report an unusual uterine polypoid mesenchymal tumor in a 52-year-old resembling the soft tissue neoplasm ossifying fibromyxoid tumor (OFMT). The neoplasm was morphologically low-grade with hypocellular areas containing bland spindle cells in a fibromyxoid stroma, cellular areas resembling typical low-grade endometrial stromal sarcoma (LGESS), and abundant mature bone. The cellular areas were ER and CD10 positive and cyclin D1 negative, and the hypocellular areas were ER and CD10 negative, with approximately 50% of the nuclei being cyclin D1 positive. The tumor harbored a BRD8::PHF1 fusion. This fusion has been reported rarely in uterine mesenchymal neoplasms, which have been designated as LGESS or high-grade endometrial stromal sarcoma. In reporting this case, we review previously reported uterine mesenchymal neoplasms with a BRD8::PHF1 fusion. Since OFMT commonly contains PHF1 fusions, we discuss the most appropriate terminology for the neoplasm we report and suggest that it is best classified as an LGESS with OFMT-like morphology.

Proposal of Novel Binary Grading Systems for Cervical Squamous Cell Carcinoma

We compared grading systems and examined associations with tumor stroma and survival in patients with cervical squamous cell carcinoma. Available tumor slides were collected from 10 international institutions. Broders tumor grade, Jesinghaus grade (informed by the pattern of tumor invasion), Silva pattern, and tumor stroma were retrospectively analyzed; associations with overall survival (OS), progression-free survival (PFS), and presence of lymph node metastases were examined. Binary grading systems incorporating tumor stromal changes into Broders and Jesinghaus grading systems were developed. Of 670 cases, 586 were reviewed for original Broders tumor grade, 587 for consensus Broders grade, 587 for Jesinghaus grade, 584 for Silva pattern, and 556 for tumor stroma. Reproducibility among grading systems was poor (κ = 0.365, original Broders/consensus Broders; κ = 0.215, consensus Broders/Jesinghaus). Median follow-up was 5.7 years (range, 0–27.8). PFS rates were 93%, 79%, and 71%, and OS rates were 98%, 86%, and 79% at 1, 5, and 10 years, respectively. On univariable analysis, original Broders (P < 0.001), consensus Broders (P < 0.034), and Jesinghaus (P < 0.013) grades were significant for OS; original Broders grade was significant for PFS (P = 0.038). Predictive accuracy for OS and PFS were 0.559 and 0.542 (original Broders), 0.542 and 0.525 (consensus Broders), 0.554 and 0.541 (Jesinghaus grade), and 0.512 and 0.515 (Silva pattern), respectively. Broders and Jesinghaus binary tumor grades were significant on univariable analysis for OS and PFS, and predictive value was improved. Jesinghaus tumor grade (P < 0.001) and both binary systems (Broders, P = 0.007; Jesinghaus, P < 0.001) were associated with the presence of lymph node metastases. Histologic grade has poor reproducibility and limited predictive accuracy for squamous cell carcinoma. The proposed binary grading system offers improved predictive accuracy for survival and the presence of lymph none metastases.

Immunohistochemical Expression of Lymphoid Enhancer-binding Factor 1 in Low-grade Endometrial Stromal Tumors

Endometrial stromal tumors (ESTs) are uncommon uterine mesenchymal lesions. Nuclear expression of β-catenin, an indication of activated Wnt/β-catenin signaling pathway, was described in 50% to 92% of low-grade ESTs, including endometrial stromal nodule and low-grade endometrial stromal sarcoma. Activation of the Wnt/β-catenin signaling pathway leads to the translocation of β-catenin into the nucleus and interaction with the T-cell factor/lymphoid enhancer-binding factor-1 (LEF1) family of transcription factors to regulate cell proliferation, differentiation, migration, and survival. Immunohistochemical analysis of β-catenin and LEF1 was performed in 2 endometrial stromal nodules and 20 low-grade endometrial stromal sarcomas and demonstrated 90.9% and 81.8% positive rates for β-catenin and LEF1, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of β-catenin and LEF1 were 90.9% versus 81.8%, 81.0% versus 85.7%, 83.3% versus 85.7%, 89.5% versus 81.8%, respectively, in the diagnosis of low-grade ESTs. There is no statistical significance of the performance of β-catenin and LEF1 in all ESTs (P = 0.664) or in primary or metastatic/recurrent settings (P = 0.515 and 0.999, respectively). Only 3 smooth muscle tumors showed focal and weak positivity for LEF1. Our results indicate LEF1 can be a useful marker in aiding a diagnosis of low-grade EST and differentiating from smooth muscle tumors alone or in combination with β-catenin.

How Can “No Specific Molecular Profile” Heterogeneity be Reduced in Molecularly Classified Endometrial Cancer?: Prognostic Significance of L1 Cell Adhesion Molecule

This study aims to investigate the role of L1 cell adhesion molecule (L1CAM) in the prognostic assessment of endometrial cancers that have been depicted as having no specific molecular profile (NSMP) in molecular classification. This is a retrospective review of 150 patients who received the diagnosis of endometrial cancer and underwent surgery at the study center between January 2008 and January 2022. When evaluating L1CAM immunohistochemical staining, scoring was done according to the percentage of positivity in tumor cells. Accordingly, score 0 = 0%, score 1=1% to 10%, score 2 = >10% to 50% and score 3 = >50%. If the staining in tumor cells was ≥10% (scores 2 and 3), it was considered positive. The patients with L1CAM positivity had significantly more frequent lymphovascular space invasion and lymph node metastasis than patients with L1CAM negativity (P = 0.013 and P = 0.007). L1CAM expression was strongly associated with mutant p53 (P = 0.003). Recurrence was significantly higher (P = 0.001) and overall survival and progression-free survival were significantly lower in patients with L1CAM positivity (P = 0.001 for both). Seventy-nine patients (52.7%) were put into NSMP group. About 84.8% of them (n = 67) were L1CAM negative and 15.2% of them (n = 12) were L1CAM-positive. Recurrence was significantly higher (P = 0.001) and overall survival and progression-free survival were significantly lower in patients with NSMP who were positive for L1CAM (P = 0.002 and P = 0.001, respectively). This study demonstrates that L1CAM expression status may add prognostic information to endometrial cancer, particularly in the NSMP subgroup. Considering the prognostic importance of L1CAM, its use as a marker may make significant contributions to reducing prognostic heterogeneity, especially in the NSMP subgroup.

High-grade Endometrial Carcinoma With Serous and Colorectal Carcinoma-like Components: Unique Morphology in Correlation With Immunohistochemical and Molecular Findings

Endometrial carcinoma with intestinal differentiation/colorectal carcinoma-like (CRC-like) features is rare with few cases reported to date. Those described are mainly endometrioid carcinomas with intestinal differentiation. We report a case of high-grade endometrial carcinoma with serous and intestinal/CRC-like components. The gross, histologic, immunohistochemical, and molecular features are described for both components of the tumor in the initial diagnostic biopsy and subsequent resection specimen. The diagnosis of primary endometrial carcinoma with serous and CRC-like components is supported by immunohistochemical and molecular findings, as well as clinical workup. The rarity of this phenomenon poses diagnostic challenges. In addition, the literature is reviewed with specific emphasis on the molecular and pathologic features of mixed endometrial carcinomas, including those with intestinal/CRC-like features.

HER2 Status Assessment in Endometrial Serous Carcinoma: Comparative Analysis of Two Proposed Testing and Interpretation Algorithms

HER2 status is now routinely assessed in endometrial serous carcinoma (ESC) due to the reported predictive value of HER2 protein overexpression and/or gene amplification. Herein the authors compare 2 proposed testing and interpretation guidelines for HER2 in ESC. Forty-three consecutive cases of ESC that had been dually tested by both HER2 immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were interpreted using 2 sets of guidelines. Guideline set 1 (GS1) is the 2018 American Society of Clinical Oncology/College of American Pathologists guidelines for breast cancer. Guideline set 2 (GS2) is a recent proposal that is a slight modification of the enrollment criteria for the clinical trial (NCT01367002) that demonstrated a survival benefit for anti-HER2 therapy in ESC. By IHC, GS1 and GS2, respectively classified 39.5% (17/43) and 28% (12/43) of ESC as HER2-negative, 37.2% (16/43) and 53.4% (23/43) as HER2 equivocal, and 23.2% (10/43) and 18.6% (8/43) as HER2-positive (P > 0.05 for all). IHC and FISH were highly concordant at the extremes using either set of guidelines, as no cases were found to be IHC3+/FISH-negative or IHC 0-1+/FISH-positive. GS1 and GS2 were comparable regarding the proportion of IHC equivocal cases that were HER2 amplified by FISH (19% vs 23% respectively; [P = 0.71]). GS1 and GS2 displayed 98% (42/43) concordance regarding the final (IHC and/or FISH-based) classification of tumors as being HER2-positive or negative, and the same 13 cases were ultimately classified as HER2 amplified using either GS1 or GS2. One “discordant” case was classified as HER2-positive using GS2 but HER2-negative using GS1 (HER2 IHC score 2+ using both guidelines, HER2:CEP17 signal ratio of 3, HER2 signal number of 3.4). Six (14%) of the 43 cases (FISH Groups: 2, 3, and 4) would require IHC results to interpret the FISH findings using GS1. Because GS1 requires that the HER2 IHC staining be observed within a homogeneous and contiguous invasive cell population, and this is not a requirement in GS2, GS2 may be better suited for ESC given its frequently heterogeneous staining pattern. Additional studies may be required on the optimal interpretation of problematic dual-probe FISH scenarios in GS2 and the necessity for IHC correlation in such scenarios. Using either set of guidelines, our findings support a reflex testing strategy of restricting FISH testing to cases that are IHC equivocal.

Molecular Classification of Endometrial Endometrioid Carcinoma With Microcystic Elongated and Fragmented Pattern

The studies on the molecular classification of endometrioid carcinoma (EC) with microcystic, elongated, and fragmented (MELF) pattern invasion are limited. In this study, 77 cases of ECs with MELF patterns in Chinese women were collected. The molecular classification of the fifth edition of the World Health Organization was used to classify the molecular subtypes using immunohistochemistry staining (mismatch repair [MMR]-immunohistochemistry: MSH2, MSH6, MLH1, and PMS2; p53) and Sanger sequencing targeted POLE. The results showed that the prevalence of the 4 molecular subtypes in EC with MELF pattern was 6.5% (5/77) for POLE mutation, 20.8% (16/77) for MMR deficient, 11.7% (9/77) for p53-mutant, and 61.0% (47/77) for no specific molecular profile. The clinicopathological characteristics of each subtype were compared. The p53-mutant and no specific molecular profile subgroups were associated with higher International Federation of Gynecology and Obstetrics stage and International Federation of Gynecology and Obstetrics grade, deeper myometrial invasion, lymphovascular space invasion, lymph node metastasis, and absence of tumor-infiltrating lymphocytes, whereas the POLE mutation and MMR deficient subgroups were associated with lower aggressive features and prominent tumor-infiltrating lymphocytes. Progression-free survival showed that the p53-mutant and no specific molecular profile subgroups had a poorer prognosis than the POLE mutation and MMR deficient subgroups. However, lymph node metastasis was an independent factor associated with a higher risk of disease recurrence in multivariate analysis. In conclusion, ECs with MELF patterns can be divided into 4 molecular subtypes with discrepancies in aggressive clinicopathological characteristics and tumor-infiltrating lymphocytes. Molecular classification has clinical significance in a morpho-molecular approach for ECs with MELF patterns.

Estrogen/Progesterone Receptor Expression and Cancer Antigen 125 Level as Preoperative Predictors to Estimate Lymph Node Metastasis in Endometrioid Endometrial Cancer

Loss of estrogen receptor/progesterone receptor (ER/PR) in endometrial cancer (EC) is associated with tumor progression and poor outcomes. Elevated pretreatment cancer antigen 125 (CA 125) level is a risk factor for lymph node metastasis (LNM). We evaluated whether the combination of ER/PR expression and CA 125 level could be used as a biomarker to predict LNM. We retrospectively investigated patients with endometrioid EC who underwent complete staging surgery during January 2015 to December 2020. We analyzed ER/PR status using immunohistochemical staining, and quantified its expression using the sum of both ER/PR H-scores. Receiver operating characteristic curves were used to identify optimal cutoff values of H-score and CA 125 levels for predicting LNM. A nomogram for predicting LNM was constructed and validated by bootstrap resampling. In 396 patients, the optimal cutoff values of the ER/PR H-score and CA 125 were 407 (area under the receiver operating characteristic curve: 0.645, P=0.001) and 40 U/mL (area under the receiver operating characteristic curve: 0.762, P<0.001), respectively. Multivariate analysis showed that CA 125 ≥40 UmL (odds ratio: 10.02; 95% CI: 4.74–21.18) and ER/PR H-score <407 (odds ratio: 4.20; 95% CI: 1.55–11.32) were independent predictors. An LNM predictive nomogram was constructed using these 2 variables and our model yielded a negative predictive value and negative likelihood ratio of 98.3% and 0.14, respectively. ER/PR expression with pretreatment CA 125 levels can help estimate LNM risk and aid in decision-making regarding the need for lymphadenectomy in patients with endometrioid EC.

Perceptions of Controversies and Unresolved Issues in the 2014 FIGO Staging System for Endometrial Cancer: Survey Results From Members of the International Society of Gynecological Pathologists and International Gynecologic Cancer Society

Long-standing controversial and unresolved issues in the current “International Federation of Gynecology and Obstetrics” staging system for endometrial cancer are well-recognized by pathologists and clinicians alike and exist primarily as a result of limitations to the existing literature. To guide the design of future outcome-based studies specifically aimed at resolving such gaps, the International Society of Gynecologic Pathologists developed a survey of the current perceptions of pathologists (n = 172) and clinicians (n= 135) from the International Society of Gynecological Pathologists and from the International Gynecologic Cancer Society on areas for potential refinement of the current International Federation of Gynecology and Obstetrics staging system. The highest priority issues for pathologists and clinicians alike were the need to determine whether stage IIIA patients (ovarian/fallopian tube involvement) can be reliably separated into favorable versus unfavorable outcome groups to avoid over-treatment of the former group and to determine whether stage IIIC patients (lymph node metastases) can be separated into favorable versus unfavorable outcome groups based on the size of lymph node metastases. The majority of pathologists and clinicians viewed lymphovascular space invasion as an independent prognostic variable and favored incorporating lymphovascular space invasion into staging, though the level of support did not meet the threshold of 75% in support that we used to define a formal consensus. While pathologists did agree on the prognostic value of reporting the extent of lymphovascular space invasion, there was no consensus on the diagnostic criteria to distinguish focal versus substantial involvement. The majority of pathologists and clinicians viewed that a universally accepted protocol for sentinel lymph node ultra-staging is lacking. Both survey groups conveyed a slight preference for incorporating tumor histotype and molecular classification into staging but the support was short of the 75% threshold for formal consensus. Collectively, this survey permits the International Society of Gynecological Pathologists to develop a pathologist and clinician-driven long-term strategy for prioritizing and designing outcome-based studies specifically targeted to resolving controversial and unresolved issues in the International Federation of Gynecology and Obstetrics staging of endometrial cancer.

ZC3H7B-BCOR Fusion High-grade Endometrial Stromal Sarcoma With Morphologic Features of Low-grade Endometrial Stromal Sarcoma. A Case Report and Review of Literature

High-grade endometrial stromal sarcomas with ZC3H7B-BCOR fusion are rare. They are predominantly located in the endomyometrium, with morphologic features characterized as haphazardly arranged fascicles of spindle cells with mild to moderate atypia, abundant myxoid matrix, high mitotic index, and tongue-like/pushing patterns of myometrial invasion. Furthermore, conventional or variant low-grade endometrial stromal sarcomas are often not present. Clinically, they present at a higher stage and are associated with worse prognosis compared with low-grade endometrial stromal sarcoma. Given the limited number of reported cases, we describe the case of a ZC3H7B-BCOR fusion high-grade endometrial stromal sarcoma initially diagnosed on the hysterectomy specimen as low-grade endometrial stromal sarcoma based on an endometrial stromal tumor showing tongue-like myometrial and lymphovascular invasion, minimal cytologic atypia, low-mitotic activity (0–1/10 high-power field), round/spindle cell component and immunohistochemical stain results (positive for CD10, estrogen receptor, progesterone receptor, and focally positive for cyclin D1). At the time of pathologic diagnosis, she was Stage Ia and managed conservatively. Subsequent molecular analysis revealed a ZC3H7B (exon 10)-BCOR (BCL-6 corepressor) (exon 7) gene fusion. On follow-up, she showed no evidence of disease at 37 months from the time of diagnosis. This case report expands the morphologic spectrum of ZC3H7B-BCOR fusion high-grade ESS, which includes an intramural location, morphologic and immunophenotypic features similar to LG-ESS, as well as the presence of round and spindle cell components. This case also underscores the value of molecular analysis in the proper classification of ESS.

NTRK-Fusion Sarcoma of the Uterine Cervix: Report of 2 Cases With Comparative Clinicopathologic Features

NTRK1/2/3 rearrangements have been identified as oncogenic drivers in a variety of tumors including those in the uterine cervix, and rarely, the uterine corpus. We report 2 cases of cervical sarcoma with NTRK gene rearrangements. Case 1 was a 54-yr-old woman who presented with postmenopausal bleeding and a 5.4 cm friable mass in the cervix. Microscopic examination of the tumor revealed proliferation of epithelioid and spindle cells arranged in alternating hypercellular and hypocellular areas, with subtle fibrosarcoma-like features. Coagulative tumor cell necrosis and readily recognizable mitoses (up to 40 mitotic figures per 10 high-power fields) were identified. Case 2 was a 52-yr-old woman who presented with abnormal vaginal bleeding and a 1.3 cm cervical mass. The resected cervical tumor showed proliferation of spindled cells with fascicular and storiform growth pattern, infiltrating into the smooth muscle with entrapment of normal endocervical glands. The tumor cells displayed mild cytologic atypia and low mitotic activity (1 mitotic figure per 10 high-power fields). The mixed inflammatory infiltrate was seen throughout the lesion, mimicking morphology of inflammatory myofibroblastic tumor. Immunohistochemical staining for S100 and CD34 demonstrated variable expression in case 1 and uniformly diffuse positivity in case 2. The tumor cells in both cases were focally positive for CD10, Cyclin D1, ER, and PR, and negative for AE1/AE3, desmin, SOX10, HMB-45. RNA fusion analysis identified SPECC1L-NTRK3 gene rearrangements in case 1 and TPM3-NTRK1 in case 2; DNA-based mutational analysis also revealed CDKN2A/B homozygous deletion in case 1. Despite accumulating literature on NTRK fusion mesenchymal tumors in gynecologic pathology, these tumors are still rare and lack well-established morphologic diagnostic criteria. Diagnostic and clinical recognition of these tumors is critical given the potential patient benefit from targeted therapy.

High-grade Endometrial Carcinoma With a Hepatoid Carcinoma-like Component

Endometrial carcinoma with hepatoid differentiation is rare and <20 reported cases have been reported as endometrial hepatoid carcinoma (EHC). We present a case of EHC associated with serous carcinoma in a 76-yr-old Japanese woman. The hepatoid component showed trabecular, pseudoglandular, and diffuse proliferation of hepatoid cells. The hepatoid cells were positive for α-fetoprotein, Hep-Per-1, glypican 3, and HNF-1β, weakly and focally positive for SALL4, and negative for PAX8. Both of the serous and hepatoid components showed overexpression of p53. The serum α-fetoprotein on postoperative day 5 was 3691 ng/mL. The postoperative course has remained uneventful for 4 yr. These findings suggested that EHC developed from serous carcinoma by acquiring hepatocytic features and losing Müllerian features. Both serous and hepatoid components showed p53 overexpression, suggesting they share a TP53 mutation as a common primary driver.

Endometrioid Adenocarcinoma Resembling Cutaneous Pilomatrix Carcinoma: A Case Report of an Aggressive Neoplasm in a Young Woman With Diffusely Aberrant Beta-catenin Expression and Associated Morular Metaplasia and Atypical Polypoid Adenomyoma–type Change

Endometrioid carcinoma with histopathologic resemblance to cutaneous pilomatrix carcinoma with mutations in the gene encoding beta-catenin, CTNNB1 are rare. There are minimal numbers of reports of high-grade tumors with this divergent differentiation in the literature. We report the case of a 29-yr-old female with an unusual presentation of endometrial cancer with overall histologic appearance indicative of a recently reported aggressive subtype of Federation of Gynecology and Obstetrics (FIGO) IVB grade 3 endometrioid carcinoma with features resembling cutaneous pilomatrix carcinoma. She was treated with a primary chemotherapy regimen with an initial significant response to treatment before developing symptomatic brain metastasis for which she underwent whole-brain radiotherapy. We discuss the unusual histologic and radiologic presentation as well as her individual management throughout this case report. The apparent association with morular metaplasia and atypical polypoid adenomyoma suggests that this rare carcinoma is within a spectrum of lesions associated with aberrant beta-catenin expression/beta-catenin mutation. Its aggressive nature highlights the importance of early recognition of this rare lesion.

Data Set for the Reporting of Endometrial Cancer: Recommendations From the International Collaboration on Cancer Reporting (ICCR)

Endometrial cancer is one of the most common cancers among women. The International Collaboration on Cancer Reporting (ICCR) developed a standardized endometrial cancer data set in 2011, which provided detailed recommendations for the reporting of resection specimens of these neoplasms. A new data set has been developed, which incorporates the updated 2020 World Health Organization Classification of Female Genital Tumors, the Cancer Genome Atlas (TCGA) molecular classification of endometrial cancers, and other major advances in endometrial cancer reporting, all of which necessitated a major revision of the data set. This updated data set has been produced by a panel of expert pathologists and an expert clinician and has been subject to international open consultation. The data set includes core elements which are unanimously agreed upon as essential for cancer diagnosis, clinical management, staging, or prognosis and noncore elements which are clinically important, but not essential. Explanatory notes are provided for each element. Adoption of this updated data set will result in improvements in endometrial cancer patient care.

An Unusual Endometrial Stromal Neoplasm With JAZF1-BCORL1 Rearrangement

Endometrial stromal tumors represent the second most common category of uterine mesenchymal tumors. Several different histologic variants and underlying genetic alterations have been recognized, one such being a group associated with BCORL1 rearrangements. They are usually high-grade endometrial stromal sarcomas, often associated with prominent myxoid background and aggressive behavior. Here, we report an unusual endometrial stromal neoplasm with JAZF1-BCORL1 rearrangement and briefly review the literature. The neoplasm formed a well-circumscribed uterine mass in a 50-yr-old woman and had an unusual morphologic appearance that did not warrant a high-grade categorization. It was characterized by a predominant population of epithelioid cells with clear to focally eosinophilic cytoplasm growing in interanastomosing cords and trabeculae set in a hyalinized stroma as well as nested and fascicular growths imparting focal resemblance to a uterine tumor resembling ovarian sex-cord tumor, PEComa, and a smooth muscle neoplasm. A minor storiform growth of spindle cells reminiscent of the fibroblastic variant of low-grade endometrial stromal sarcoma was also noted but conventional areas of low-grade endometrial stromal neoplasm were not identified. This case expands the spectrum of morphologic features seen in endometrial stromal tumors, especially when associated with a BCORL1 fusion and highlights the utility of immunohistochemical and molecular techniques in the diagnosis of these tumors, not all of which are high grade.

Correlative Assessment of p53 Immunostaining Patterns and TP53 Mutation Status by Next-Generation Sequencing in High-Grade Endometrial Carcinomas

TP53 mutations are frequently identified in the copy number-high molecular subgroup of endometrial carcinomas (ECs). P53 immunohistochemistry (IHC) is a widely used surrogate marker reflecting the mutational status of TP53, and recent reports have shown ~95% concordance between the two methods in ECs. While these results are promising, studies evaluating the correlation between different p53 IHC staining patterns and comprehensive next-generation sequencing results are still limited. We compared the p53 IHC staining patterns, scored as wild-type, diffuse nuclear overexpression, null/complete absence, and cytoplasmic, to next-generation sequencing results reported by FoundationOneCDx in 43 high-grade ECs: 20 serous ECs, 9 mixed ECs with a serous component, 4 carcinosarcomas with a serous component, and 10 grade 3 endometrioid ECs. The concordance of p53 IHC and TP53 mutation status was 100% (43/43) overall, including 100% (33/33) concordance in tumors with a serous component and 100% (10/10) in endometrioid ECs. Among the 35 tumors with aberrant p53 expression the most commonly observed pattern was diffuse nuclear overexpression seen in 69% (24/35), followed by cytoplasmic staining in 17% (6/35), and complete absence of staining (null) in 14% (5/35) of tumors. Of the 6 tumors with cytoplasmic staining, 4 corresponded to missense mutations within the DNA binding domain (V157F in 2 tumors, and S127P and R280S, in 2 tumor each), while 2 corresponded to nonsense mutations in the tetramerization domain (p.E339*). Our results further support that p53 IHC can serve as an accurate predictor of TP53 alterations in ECs to aid the molecular-based tumor classification and the distinction between tumor histotypes, both of which play an important role in the assessment of clinical prognosis and therapeutic decision making. In addition, our data suggest, that the type and position of TP53 mutation may not directly correlate with the observed p53 IHC pattern in all tumors, and that there may be alternative mechanisms for cytoplasmic localization (other than mutations involving the nuclear localization domain), possibly due to conformational changes or posttranslational modifications of the aberrant p53 protein.

Targeted Molecular Testing in Endometrial Carcinoma: Validation of a Clinically Driven Selective ProMisE Testing Protocol

Incorporation of molecular classification into clinicopathologic assessment of endometrial carcinoma (EC) improves risk stratification. Four EC molecular subtypes, as identified by The Cancer Genome Atlas, can be diagnosed through a validated algorithm Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) using p53 and mismatch repair (MMR) protein immunohistochemistry (IHC), and DNA polymerase epsilon (POLE) mutational testing. Cost and access are major barriers to universal testing, particularly POLE analysis. We assessed a selective ProMisE algorithm (ProMisE-S): p53 and MMR IHC on all EC’s with POLE testing restricted to those with abnormal MMR or p53 IHC (to identify POLEmut EC with secondary abnormalities in MMR and/or p53) and those with high-grade or non-endometrioid morphology, stage >IA or presence of lymphovascular space invasion (so as to avoid testing on the lowest risk tumors). We retrospectively compared the known ProMisE molecular classification to ProMisE-S in 912 EC. We defined a group of “very low-risk” EC (G1/G2, endometrioid, MMR-proficient, p53 wild-type, stage IA, no lymphovascular space invasion) in whom POLE testing will not impact on patient care; using ProMisE-S, POLE testing would not be required in 55% of biopsies and 38% of all EC’s, after evaluation of the hysterectomy specimen, in a population-based cohort. “Very low-risk” endometrioid EC with unknown POLE status showed excellent clinical outcomes. Fifteen of 166 (9%) of all p53abn EC showed G1/G2 endometrioid morphology, supporting the potential value of universal p53 IHC. The addition of molecular testing changed the risk category in 89/896 (10%) EC’s. In routine practice, POLE testing could be further restricted to only those patients in whom this would alter adjuvant therapy recommendations.

Prognostic Significance of Size, Location, and Number of Lymph Node Metastases in Endometrial Carcinoma

Regional lymph node metastasis is a well-established negative predictive prognostic factor in endometrial carcinomas. Recently, our approach to the pathologic evaluation of lymph nodes in endometrial carcinomas has changed, mainly due to the utilization of immunohistochemical stains in the assessment of sentinel lymph nodes, which may result in the identification of previously unrecognized disease [particularly isolated tumor cells (ITCs)] on hematoxylin and eosin stained slides. However, the clinical significance of this finding is not entirely clear. Following the experience in other organs systems such as breast, the Eight Edition of the American Joint Committee on Cancer’s Cancer Staging Manual has recommended utilizing the N0(i+) terminology for this finding, without impact in the final tumor stage. We performed a comparative retrospective multi-institutional survival analysis of 247 patients with endometrial carcinoma with regional lymph node metastasis of various sizes identified in nonsentinel lymphadenectomy, demonstrating that the cumulative survival of patients with isolated tumor cells in regional lymph nodes is not statistically different from patient with negative lymph nodes, and is statistically different from those with lymph nodes showing micrometastasis or larger metastatic deposits. In addition, we evaluated the prognostic implications of the number of involved regional lymph nodes, demonstrating a worsening prognosis as the number of involved lymph nodes increases from none to one, and from one to more than one. Our data suggests that regional lymph nodes with isolated tumor cells in patients with endometrial carcinoma should likely be considered, for staging purposes, as negative lymph nodes, simply indicating their presence with the (i+) terminology.

Metastatic Cholangiocarcinoma to the Uterus Morphologically Imitating Primary Intestinal-type Endometrioid Adenocarcinoma

Cholangiocarcinoma is an uncommon and aggressive malignancy of intrahepatic and extrahepatic bile ducts. We present a case of a 37-year-old woman with cholangiocarcinoma metastatic to the endometrium that mimicked a primary endometrial adenocarcinoma at resection. The patient is status-post orthotopic liver transplant for cholangiocarcinoma. She presented for evaluation of a clear, odorless vaginal discharge of 6 months’ duration. Endometrial biopsy demonstrated an adenocarcinoma with mucinous features similar to primary endometrial adenocarcinoma, but with an immunophenotype consistent with metastatic cholangiocarcinoma. Subsequent hysterectomy demonstrated complete replacement of the native endometrium, a presentation that represents, to our knowledge, the first such reported in the literature. Overall, extragenital metastatic disease to the uterine corpus is rare and involvement of the endometrium even less common. Metastatic cholangiocarcinoma represents a small subset of these metastases to the uterus.

An Unusual Benign Uterine Stromal Spindle Cell Tumor Harboring JAZF1::BCORL1

Uterine mesenchymal lesions demonstrate various underlying genomic alterations involving MED12, JAZF1, YWHAE, BCOR, and ALK genes, among others. Recent publications describe a subset of high-grade endometrial stromal sarcoma lesions harboring BCORL1 gene aberrations including JAZF1::BCORL1. Herein, we present an unusual benign endomyometrial spindle cell lesion that defies classificatory efforts by demonstrating mixed histomorphologic and immunohistochemical features of endometrial stromal nodule, leiomyoma, and uterine inflammatory myofibroblastic tumor while harboring a JAZF1::BCORL1. The lesion was found in a 43-yr-old woman with pelvic pain and heavy menses as a 5.5 cm well-circumscribed ulcerated mass fungating from the cervical os. Microscopic examination revealed a polypoid, well-circumscribed, moderately cellular endomyometrial tumor composed by bland spindle cells haphazardly disposed within a slightly edematous stroma enriched by a delicate network of thin-walled vessels that were occasionally encircled by the tumor cells. Unequivocal evidence of tongue-like growth pattern into the myometrium, tumor-type necrosis or increased mitotic activity was not identified after sampling the entire lesion. The lesion showed patchy immunoreactivity for both smooth muscle actin-alpha and desmin while negative for CD10, HMB45, ALK (D5F3), and BCOR. An Archer FusionPlex panel assay demonstrated a fusion involving both exons 4 from the JAZF1 and BCORL1 genes. The JAZF1::BCORL1 has not, to the best of our knowledge, been previously reported in a benign/low-grade mesenchymal uterine lesion.

CTNNB1-mutated High-grade Endometrioid Carcinoma With Extensive Squamous and Shadow Cell Differentiation Can Mimic Pilomatrix Carcinoma

Evaluation of Saccharomyces cerevisiae–like 1 (SEC14L1) in Gynecologic Malignancies Shows Overexpression in Endometrial Serous Carcinoma

Saccharomyces cerevisiae–like 1 (SEC14L1) is a member of the SEC14 family and is involved in liposoluble vitamin transfer, and in a large cohort of breast cancer cases, was one of the genes most significantly associated with lymphovascular invasion (LVI), and had a significant relationship with human epidermal growth factor receptor 2 status, survival, and histologic grade. In this study, 111 separate gynecologic tumors were studied for SEC14L1 protein expression, including: uterine adenosarcoma, ovarian clear cell carcinoma, endometrial stromal sarcoma, endometrioid carcinoma of the uterus, high-grade serous carcinoma, ovarian endometrioid carcinoma, uterine leiomyosarcoma, low-grade serous carcinoma, uterine carcinosarcoma, and uterine serous carcinoma (USC). Overall, LVI was noted in 31/111 (28%) cases, highest in uterine carcinosarcoma (5/11; 45%), high-grade serous carcinoma (9/21; 43%), and ovarian clear cell carcinoma (4/10; 40%). SEC14L1 was positive in 25/111 (23%) cases; the highest percentage and only statistically significant finding by tumor type was USC at 9/12 (75%) cases positive. No relation between LVI or survival and SEC14L1 expression was noted. The relation between USC, a tumor known to show human epidermal growth factor receptor 2 overexpression and SEC14L1 is a novel finding, the significance of which warrants further study.

Microscopic Sertoliform Sex Cord Proliferations: A Rare Incidental Finding Associated With Endometriosis and Ovarian Epithelial Neoplasia

Microscopic sex cord proliferations are a rare incidental finding seen in association with ovarian and uterine stromal or epithelial neoplasms and more uncommonly non-neoplastic conditions such as endometriosis and adenomyosis. They may also occur in the absence of other pathology, as an incidental finding in the ovaries of pregnant women and in heterotopic locations such as the fallopian tube. Most reports of this phenomenon describe adult granulosa cell tumor-like morphology. Herein, we describe 4 cases of microscopic sex cord proliferations with Sertoliform features, occurring in the stromal component of endometriosis or in the wall of an epithelial ovarian neoplasm; 2 of the patients with endometriosis had concurrent endometrioid adenocarcinoma (1 uterine corpus, 1 ovary). The proliferations were positive with sex cord markers inhibin and calretinin. As far as we are aware, such Sertoliform proliferations have not been reported previously in endometriosis and have only rarely been described in association with ovarian epithelial neoplasia. It is likely that such proliferations represent a benign non-neoplastic phenomenon. Awareness of this phenomenon is important in order to avoid misdiagnosis as a sex cord or other neoplasm. In reporting this unusual phenomenon, we review incidental sex cord and sex cord-like proliferations in the female genital tract.

Uterine Endometrial Stromal Tumors With Limited Infiltration: First Report of a Case Series Indicating Potential for Malignant Behavior

The distinction between a uterine endometrial stromal nodule (ESN) and low-grade endometrial stromal sarcoma (LGESS) is based on the nature of the interface between the lesion and the surrounding myometrium and the presence or absence of vascular invasion. Most LGESS exhibit widespread irregular myometrial invasion with or without vascular invasion, whereas ESNs are well-circumscribed without vascular invasion. Tavassoli and Norris proposed that minor marginal irregularity (up to 3 protrusions, each <3 mm beyond the main mass) is allowable in an ESN and these criteria have been incorporated into the World Health Organization Classification. There is a small group of neoplasms with marginal irregularity greater than that allowable in ESN but without the widespread myometrial infiltration typical of most LGESS. Such neoplasms have been categorized as endometrial stromal tumor with limited infiltration but there have been no studies which have provided follow-up in this group of neoplasms. We aimed to determine the clinical behavior of this uncommon group of neoplasms. From a series of 19 endometrial stromal tumors with limited infiltration, mainly from consultation practice, we obtained follow-up information in 16 cases by contacting referring pathologists and clinicians. The patient age ranged from 32 to 84 yr (median: 54 yr) and follow-up ranged from 16 to 187 mo (median: 52 mo). Two of 16 patients (12.5%) developed metastatic disease to the small intestine and peritoneum (1 case-metastasis at 23 mo) and bone and lung (1 case-humeral metastasis at 135 mo; lung and sacral metastases subsequently). No patient died from disease during the follow-up period. A small percentage of endometrial stromal tumors with limited infiltration exhibit malignant behavior with distant metastasis. Such neoplasms should be regarded as potentially malignant and the term LGESS with limited infiltration is an appropriate designation.

Two Cases of Mesonephric-like Carcinoma Arising From Endometriosis: Case Report and Review of the Literature

Endometriosis is a common condition in reproductive age women that is defined as the presence of endometrial tissue (epithelial and/or stromal) outside the uterine corpus. While not a premalignant lesion, it is a condition with a potential for malignancy, especially in the ovaries. Notable endometriosis-associated neoplasms include clear cell carcinoma and endometrioid adenocarcinoma of the ovaries. There have been recent reports of mesonephric-like adenocarcinoma (MLA) of the ovary, a very rare neoplasm with similar morphologic and immunophenotypic characteristics as mesonephric adenocarcinoma, however, without an association with mesonephric remnants. Some of these cases have been associated with endometriosis. Here, we describe 2 cases of MLA arising directly from endometriosis. In both cases, there was evidence of endometriosis contiguous with the tumor and invasion from other sources was excluded. The immunophenotypes of both tumors were typical of mesonephric adenocarcinoma except PAX-8 was strongly positive suggesting a Mullerian origin. Molecular testing on one of the cases revealed KRAS and P53 mutations. We review published findings of MLA and associated endometriosis. This report describes the sixth and seventh reported cases of MLA associated with endometriosis and the first reported cases of MLA arising directly from endometriosis and associated with other forms of epithelial proliferation within endometriosis. These 2 cases provide potential evidence that MLA should be considered an endometriosis-associated neoplasms.

Pilomatrix-like High-grade Endometrioid Carcinoma is a Morphologically and Immunophenotypically Distinct Entity and May Show Mismatch Repair Deficiency

Unusual Ovarian Tumors With Endometrioid Proliferations Co-Expressing Estrogen Receptor and CDX-2 Arising in Cystadenofibromatous Background: Report of 3 Cases

This report describes 3 cases of ovarian tumors with unusual glandular proliferations co-expressing estrogen receptor and CDX-2 by immunohistochemistry set in cystadenofibromatous background. Targeted next-generation sequencing was performed on the cyst lining epithelium and glandular proliferations for all cases; CTNNB1 mutations were detected in the glandular proliferations of all neoplasms. The cyst lining of case 1 demonstrated a different CTNNB1 mutation from the matched glandular proliferation. No mutations were detected in the cyst lining from case 2. The cyst lining and glandular proliferation for case 3 harbored identical ATM and PIK3CA mutations with an additional CTNNB1 mutation in the glandular proliferation. To our knowledge, this is the first reported series of endometrioid proliferations with co-expression of estrogen receptor and CDX-2 in cystadenofibromatous background.

Immunoreactive Acellular Keratin in Sentinel Lymph Nodes From a Patient With Endometrioid Carcinoma of the Endometrium With Squamous Differentiation: A Case Report of a Potential Diagnostic Pitfall

Sentinel lymph node biopsy is gaining increasing acceptance as a less morbid way to assess lymph node status in patients with endometrial carcinoma, compared with full pelvic node dissection. The sentinel nodes are usually subjected to ultrastaging, with sections taken at multiple levels from each block and immunstaining for keratin performed, in order to detect micrometastses. We report a case of an 80-yr-old woman who underwent a right sentinel lymph node biopsy at the time of surgery for clinically and radiologically apparent stage I endometrial endometrioid adenocarcinoma. The immunostains for AE1/AE3 performed on the 2 right pelvic sentinel lymph nodes were positive, corresponding to subcapsular acellular keratin on hematoxylin and eosin; however, carcinoma cells could not be identified on the hematoxylin and eosin–stained slides. Immunomarkers for Ber-EP4 and EMA, both of which were strongly expressed in the endometrial carcinoma cells, were negative on the nodal tissue, and we concluded that the sentinel lymph nodes were negative for metastatic carcinoma, despite the positive keratin immunostains. To our knowledge, this unusual finding is not described in the literature; recognition of this phenomenon and study of additional cases is warranted.

A Multiplex SNaPshot Assay is a Rapid and Cost-Effective Method for Detecting POLE Exonuclease Domain Mutations in Endometrial Carcinoma

Determining the replicative DNA polymerase epsilon (POLE) mutation status in endometrial carcinomas (ECs) has important clinical implications given that the majority of “ultramutated” tumors harboring pathogenic exonuclease domain mutations in POLE (POLEmut) have a favorable prognosis, even among high-grade histotypes. Currently, there are no specific morphologic or immunophenotypic features that allow accurate detection of POLEmut tumors without molecular testing. Consequently, identifying POLEmut tumors has been challenging without employing costly and/or time-consuming DNA sequencing approaches. Here we developed a novel SNaPshot assay to facilitate routine and efficient POLE mutation testing in EC. The SNaPshot assay interrogates 15 nucleotide sites within exons 9, 11, 13, and 14 encoding the POLE exonuclease domain. The variant sites were selected based on recurrence, evidence of functional impact, association with high tumor mutation burden and/or detection in EC clinical outcome studies. Based on the pathogenic somatic variants reported in the literature, the assay is predicted to have a clinical sensitivity of 90% to 95% for ECs. Validation studies showed 100% specificity and sensitivity for the variants covered, with expected genotypic results for both the positive (n=11) and negative (n=20) patient controls on multiple repeat tests and dilution series. Analytic sensitivity was conservatively approximated at a 10% variant allele fraction (VAF), with documented detection as low as 5% VAF. As expected, the SNaPshot assay demonstrated greater sensitivity than Sanger sequencing for VAFs below 20%, an important characteristic for somatic mutation detection. Here we have developed and validated the first SNaPshot assay to detect hotspot POLE mutations. While next-generation sequencing and Sanger sequencing-based approaches have also been used to detect POLE mutations, a SNaPshot approach provides useful balance of analytical sensitivity, cost-effectiveness, and efficiency in a high-volume case load setting.

Androgen Receptor Immunohistochemical Expression in Undifferentiated/Dedifferentiated Endometrial Carcinoma

Uterine undifferentiated (UC)/dedifferentiated (DEAC) carcinomas are rare malignant neoplasms. They tend to pursue an aggressive clinical course with an advanced stage at presentation. It has been found that androgen receptor (AR) might play a role as a prognostic and therapeutic marker in endometrial carcinoma. However, its expression in UC/DEAC has not been investigated. Herein, the aim of this study was to evaluate the expression of AR along with estrogen receptor (ER), progestin receptor (PR), and HER2 in UC/DEAC and also in other subtypes of high-grade endometrial carcinomas. Review of our pathology database over the period of 2011 to 2019 identified 16 UC/DEAC cases (N=16). We also randomly selected other high-grade endometrial carcinomas including FIGO 3 endometrioid carcinoma (N=9), serous carcinoma (N=8), clear cell carcinoma (N=12) and carcinosarcoma (N=10) for comparison. Immunohistochemical stains for AR, ER, PR, and HER2 were performed on all 55 cases. The protein expression was evaluated both quantitatively and qualitatively. In DEAC cases both the undifferentiated component and the well-differentiated component were recorded separately. Overall, variable degrees of AR reactivity (by Allred scoring method) was present in 63% of UC/DEACs(10/16), 67% of FIGO 3 endometrioid carcinomas (6/9), 88% of serous carcinomas (7/8), 80% of carcinosarcomas (8/10), and 9% of clear cell carcinoma (1/12). AR expression was most often seen with PR (70%) or ER (60%) staining in UC/DEACs. Thirteen cases of UC/DEACs were positive for at least 1 hormone receptor. HER2 was negative in all UC/DEACs. Almost all other high-grade carcinoma cases were negative for HER2 except 20% of carcinosarcoma (2/10) and 13% of serous carcinoma (1/8) which showed 3+ HER2. Loss of AR appears to be associated with worse clinicopathologic parameters in UC/DEAC. AR is highly expressed in UC/DEAC, and in the majority of FIGO 3 endometrioid carcinomas, serous carcinomas, and carcinosarcoma. These findings suggest a potential role for androgen inhibitors in the management of patients with these tumors.

The Correlation of Histopathologic Parameters With Mismatch Repair Protein-deficient Subgroups and MLH1 Methylation in Endometrial Carcinomas

There are limited data regarding the correlation of clinical and pathologic parameters with mismatch repair (MMR) protein-deficient subgroups and methylation status. In this study, we analyzed the status of MMR proteins in resection specimens of 198 consecutive endometrial carcinomas and the methylation status in tumors with MLH1 and PMS2 deficiency. We, therefore, assessed the correlation of clinical and pathologic parameters with MMR protein-deficient subgroups. Univariate analysis revealed that deeper myometrial invasion and the presence of tumor-associated lymphocytes were more frequently observed in tumors with MMR protein deficiency (P=0.023 and 0.001, respectively). The multivariate logistic regression analysis revealed that only the presence of tumor-associated lymphocytes was significantly associated with MMR protein deficiency (P=0.002, odds ratio=2.674, 95% confidence interval=1.418–5.045). We also compared MLH1 and PMS2 deficiency with other protein deficiency regarding clinical and pathologic parameters. Furthermore, we compared MLH1 methylated tumors with MMR protein-deficient nonmethylated tumors regarding clinical and pathologic parameters. MLH1 was methylated in 51 of 54 tumors with MLH1 and PMS2 deficiency. In univariate analysis, a larger tumor size was significantly associated with MLH1 and PMS2 deficiency and with MLH1 methylation (P=0.004 and 0.005, respectively). The multivariate logistic regression analysis revealed that a larger tumor size was significantly associated with MLH1 and PMS2 deficiency and MLH1 methylation (P=0.002, odds ratio=14.222, 95% confidence interval=2.560–79.026, P=0.008, odds ratio=22.222, 95% confidence interval=2.220–222.395, respectively). Our results showed a slightly higher rate of MLH1 and PMS2 deficiency (34.3%) than in previous studies. This may likely be due to ethnic differences in frequency of various mutations.

Substantial Lymphovascular Space Invasion Is an Adverse Prognostic Factor in High-Risk Endometrial Cancer

Approximately 15% of patients with endometrial cancer present with high-risk disease (HREC). Moreover, assessing the extent of lymphovascular space invasion (LVSI) may provide prognostic insight among patients with HREC. The aim of this study was to determine whether the extent of LVSI can serve as a prognostic factor in HREC. All cases of ESMO-ESGO-ESTRO 2016 classified HREC in the Danish Gynecological Cancer Database (DGCD) diagnosed from 2005 to 2012 were reviewed for the presence and extent of LVSI (categorized using a 3-tiered definition). We used the Kaplan-Meier analysis to calculate actuarial survival rates, both adjusted and unadjusted Cox regression analyses were used to calculate the proportional hazard ratio (HR). A total of 376 patients were included in our analysis. Among 305 patients with stage I/II HREC, 8.2% and 6.2% had focal or substantial LVSI, respectively, compared with 12.7% and 38.0% of 71 patients with stage III/IV HREC, respectively. Moreover, the estimated 5-yr recurrence-free survival rate was significantly lower among patients with substantial LVSI compared with patients with no LVSI for both stage I/II (HR: 2.8; P=0.011) and stage III/IV (HR: 2.9; P=0.003) patients. Similarly, overall survival was significantly lower among patients with substantial LVSI for both stage I/II (HR: 3.1; P<0.001) and stage III/IV (HR: 3.2; P=0.020) patients. In patients with HREC, substantial LVSI is an independent adverse prognostic factor for lymph node and distant metastases, leading to reduced survival. Thus, the extent of LVSI should be incorporated into routine pathology reports in order to guide the appropriate choice of adjuvant treatment.

Description of a Novel ERBB4-rearranged Uterine Sarcoma

High-grade endometrial stromal sarcoma (HGESS) is an uncommon tumor accounting for <1% of all uterine malignancies. Currently this designation is largely reserved for neoplasms harboring YWHAE-NUTM2A/B and ZC3H7B-BCOR translocations. Here, we report a novel CIQTNF1-ERBB4 translocation in a uterine neoplasm arising in a 49-yr-old woman with morphology suggestive of HGESS. Histologic examination of the 5 cm polypoid uterine corpus mass showed a neoplasm composed of a monotonous population of cells with moderately atypical ovoid to spindle shaped nuclei with easily identifiable mitotic activity and prominent vasculature with focal intravascular extension. Immunohistochemistry showed variable positivity with desmin, estrogen receptor, progesterone receptor, AE1/3 and cyclin D1, and molecular testing showed a translocation between CIQTNF1 on chromosome 17 and ERBB4 on chromosome 2. This represents the first report of this translocation in a uterine neoplasm and adds to the growing list of translocations identified in uterine sarcomas. Although the morphology is suggestive of HGESS, this neoplasm is currently best termed an ERBB4-rearranged uterine sarcoma until additional cases are reported to more fully characterize these neoplasms.

Molecular Evaluation of Low-grade Low-stage Endometrial Cancer With and Without Recurrence

Low-grade, low-stage endometrioid carcinomas (LGLS EC) demonstrate 5-yr survival rates up to 95%. However, a small subset of these tumors recur, and little is known about prognostic markers or established mutation profiles associated with recurrence. The goal of the current study was to identify the molecular profiles of the primary carcinomas and the genomic differences between primary tumors and subsequent recurrences. Four cases of LGLS EC with recurrence and 8 cases without recurrence were evaluated via whole-exome sequencing. Three of the 4 recurrent tumors were evaluated via Oncomine Comprehensive Assay. The resulting molecular profiles of the primary and recurrent tumors were compared. Two of the 3 recurrent cases showed additional mutations in the recurrence. One recurrent tumor included an additional TP53 mutation and the other recurrent tumor showed POLE and DDR2 kinase gene mutation. The POLE mutation occurred outside the exonuclease domain. PIK3CA mutations were detected in 4 of 4 primary LGLS EC with recurrence and in 3 of 8 disease-free cases. LGLS EC with recurrence showed higher MSIsensor scores compared with LGLS without recurrence. The level of copy number gains in LGLS EC with recurrence was larger than LGLS EC without recurrence. This pilot study showed 1 of 3 recurrent cases gained a mutation associated with genetic instability (TP53) and 1 of them also acquired a mutation in the DDR2 kinase, a potential therapeutic target. We also noted a higher level of copy number gains, MSIsensor scores and PIK3CA mutations in the primary tumors that later recurred.

BCOR Internal Tandem Duplication Associated Uterine Sarcoma: Expanding the Clinicopathologic Spectrum

The diagnosis of high-grade endometrial stromal sarcoma has become more refined following molecular characterization of these tumors. Recently BCOR internal tandem duplications (ITD) have been identified in a small number of high-grade endometrial stromal sarcoma. Here we present an additional case of this rare entity in a young woman in her late teens. She presented with menorrhagia and underwent resection of 2 uterine lesions. The tumor was a spindle cell neoplasm composed of long fascicles with low to moderate cellularity, mild to moderate cytologic atypia, and up to 2 mitotic figures per 10 high power fields. Necrosis was not identified. Immunohistochemical stains showed the tumor to be positive for cyclin D1 in >50% of tumor cells, focally positive for CD10, and negative for SMA, desmin, h-caldesmon, and ALK1. BCOR ITD was confirmed by polymerase chain reaction with subsequent Sanger sequencing. Clues to the diagnosis of BCOR ITD uterine sarcoma include young patient age, uniform nuclear features, and diffuse positivity for cyclin D1. These features should prompt further molecular interrogation for definitive diagnosis, which is important for prognostication.

Associations Between Intraluminal Tumor Cell Involvement in Serially Examined Fallopian Tubes and Endometrial Carcinoma Characteristics and Outcomes

Approximately 12% of routinely examined fallopian tubes of endometrial carcinoma (EC) cases have intraluminal tumor cells (ILTCs). ILTC associations with EC characteristics and outcomes are understudied, and unknown in serially examined and embedded tubal fimbriae. Glass slides of serially examined and embedded tubal fimbriae for 371 EC cases were independently reviewed by 2 pathologists who recorded ILTC presence and characterized them as mucosal if involved and floating if not. Disagreements were reviewed by a third pathologist, and agreement between any 2 determined final ILTC status. Clinico-pathologic associations and ILTC presence were tested for significance (P<0.05) by univariable analysis, and stage and histotype determinants were included in a multivariable analysis. The Kaplan-Meier estimates and log-rank tests compared overall and EC-specific survival, and Cox proportional regression estimated hazard ratios. ILTCs were present in 56 (15.1%) cases: 30 mucosal and 26 floating. FIGO stage 3/4, lymph-vascular space invasion, deep myometrial invasion, nonendometrioid histotype, and adjunctive chemotherapy were significantly associated with ILTC presence, and only stage was significant in the multivariable analysis. Overall, 61 women died: 30 of whom died of EC. ILTCs were nonsignificantly associated with higher overall and EC-specific mortality and mucosal ILTCs had the highest hazard ratios (1.64 and 1.89, respectively). Serially examined and embedded tubal fimbriae have a higher prevalence of ILTCs than routinely examined tubes, and high FIGO stage is an independent determinant. A prognostic effect was not found, but the higher trending hazard ratios suggest additional study is needed to determine whether ILTCs and in particular mucosal ILTCs adversely affect prognosis.

A “Null” Pattern of p16 Immunostaining in Endometrial Serous Carcinoma: An Under-recognized and Important Aberrant Staining Pattern

The ability to distinguish endometrial serous carcinoma (SC) from high-grade endometrioid adenocarcinoma is of great importance given their differences in prognosis and management. In practice, this distinction typically relies upon the use of a focused immunohistochemical panel including p53, p16, and mismatch repair proteins. The expression of p16 is characteristically strong and diffuse in SCs, and weak and/or patchy in many high-grade endometrioid adenocarcinomas. Here, we report a subset of SCs that are entirely negative for p16 immunostaining, a pattern we refer to as “p16 null.” This pattern was identified in 2 of 63 cases of SC diagnosed at our institution—1 with histologically classic features and 1 with ambiguous high-grade histologic features. These tumors otherwise showed a SC signature by immunohistochemical and demonstrated an SC pattern of genetic mutations. No mutation in the gene for p16, cyclin-dependent kinase inhibitor 2A (CDKN2A), was identified in either case. However, molecular correlates for the absent p16 expression were present, including homozygous deletion of CDKN2A in one case and hemizygous deletion of CDKN2A with promotor hypermethylation of the remaining allele in the other case. To our knowledge, this constitutes the first report conclusively demonstrating the existence of a small subset of SCs that are completely negative by p16 immunohistochemistry, and the molecular lesions responsible for this pattern. In the context of an otherwise clinically and histologically classic example of SC, we endorse this “null” p16 staining pattern as an alternative aberrant staining pattern that should not deter one from committing to this diagnosis.

Comprehensive Clinicopathologic Analysis for Mismatch Repair Protein Expression in Unselected Endometrial Carcinoma Patients With an Emphasis on the Role of MLH1 Deficiency

Screening for mismatch repair (MMR) deficiency in unselected patients with endometrial carcinoma (EC) and the clinicopathologic descriptions of ECs with MMR deficiency have been well demonstrated in Western populations, but studies on Asian populations are relatively scarce. In this study, we described the clinicopathologic features of ECs according to MMR status in unselected Taiwanese patients. We also conducted subgroup analysis of MMR-deficient (dMMR) cases according to the presence or absence of MLH1. Patients diagnosed with ECs between January 2017 and February 2020 at our institution were included. Immunohistochemistry analysis of MLH1, PMS2, MSH2, and MSH6 proteins on endometrial primary tumors and clinicopathologic variables were assessed retrospectively. A total of 231 EC patients were enrolled, of whom 50 (21.6%) had dMMR tumors. Of these 50 cases, 39 had tumors that lacked MLH1 expression and 11 were positive for MLH1. The overall dMMR group was significantly related to older age, parity, and high histologic grade compared with the MMR-proficient (pMMR) group. ECs with MLH1 deficiency were obviously associated with several poor pathologic features, including high histologic grade, lymph node metastasis, and lymphovascular space invasion. Moreover, we first reported that parity and the late age at menopause are strongly correlated with MLH1-related dMMR EC group compared with pMMR group. In conclusion, triaging EC patients into pMMR, MLH1-related dMMR and non–MLH1-related dMMR groups by immunohistochemistry analysis may help clinicians to predict disease behavior and guide further management. The strong association between parity and MLH1-related dMMR ECs warrants further investigation on the underlying mechanism.

Diagnostic Accuracy in Assessment of Depth of Myometrial Invasion in Low-grade Endometrioid Carcinoma: A 2 Center Comparative Study by MRI and Intraoperative Assessment

The role of lymphadenectomy in endometrial carcinomas is controversial, especially in low-grade endometrioid carcinomas. In many institutions, lymphadenectomy in the latter neoplasms is undertaken only when there is deep myometrial invasion, defined as invasion involving 50% or more of the myometrium (FIGO stage IB). There has been considerable debate as to the best modality to detect deep myometrial invasion. In Europe, preoperative magnetic resonance imaging (MRI) is the most commonly used modality while in North America, intraoperative assessment (IOA) is undertaken in most, but not all, institutions. The aim of this study was to compare the diagnostic accuracy of these 2 modalities in identifying deep myometrial invasion in low-grade endometrioid carcinomas. Two patient cohorts were studied from Belfast, UK (n=253) and Boston, USA (n=276). With respect to detecting deep myometrial invasion, MRI had a sensitivity of 72.84%, positive predictive value of 75.64% and a positive likelihood ratio of 6.59 (95% confidence interval; 4.23–10.28). IOA had a sensitivity of 78.26%, positive predictive value of 80% and a positive likelihood ratio of 20.00 (95% confidence interval; 10.35–38.63). The superior positive likelihood ratio suggests that IOA is better than MRI in determining deep myometrial invasion and the nonoverlapping 95% confidence intervals suggest this is a significant finding. However, there are significant resource implications associated with IOA and preoperative MRI carries other advantages that are discussed herein.

Clinicopathologic and Prognostic Significance of CD47 Expression and Tumor-associated Macrophages in Endometrial Carcinoma

Tumor-associated macrophages (TAMs) influence cancer progression. CD47 is an antiphagocytic molecule aiding tumor resistance against host immune surveillance. The relationship between CD47 expression and TAM-related microenvironment in endometrial carcinoma (EC) is poorly understood. The expression and prognostic significance of CD47 and CD163-labeled TAMs in 165 EC cases was assessed with CD47 and CD163 immunohistochemical studies. CD47 expression was found in 156/165 (94.6%) cases. CD47 expression was significantly higher in nonendometrioid carcinomas. CD47 overexpression was associated with histologic grade. High epithelial and stromal TAMs counts were also associated with high tumoral CD47 expression. High epithelial, stromal, and margin TAMs counts were associated with higher histologic grade and lymphovascular invasion. Epithelial TAMs counts were higher in patients with nonendometrioid carcinomas (P=0.0001) and cases with recurrence (P=0.018). High stromal TAMs counts were associated with deeper myometrial invasion (P=0.017) and the presence of distant metastasis (P=0.024). The counts of margin TAMs was significantly correlated with the depth of myometrial invasion, lymphovascular invasion, FIGO stage, lymph node metastases, distant metastasis, and recurrence (P=0.0001, 0.0001, 0.004, 0.005, 0.014, and 0.04, respectively). CD47 expression was not associated with overall survival (OS) and progression-free survival. However, high epithelial and stromal TAM counts were associated with shorter OS. Besides, high epithelial and margin TAM counts were associated with shorter progression-free survival. Furthermore, increased stromal and margin TAM counts were determined to be an independent prognostic marker of reduced OS. TAM count is, therefore, a significant prognostic factor in EC and the CD47 assessment has potential benefit for future clinical use.

Defining Substantial Lymphovascular Space Invasion in Endometrial Cancer

Lymphovascular space invasion (LVSI) occurs in a minority of endometrial cancer (EC) cases, and the extent of LVSI is an important risk factor for recurrence and/or metastases. Our aim was to improve the reproducibility of measuring clinically meaningful LVSI by performing a quantitative analysis of the correlation between LVSI and the risk of pelvic lymph node recurrence in EC. EC samples from PORTEC-1 and PORTEC-2 trials were retrieved and used to collect quantitative data, including the number of LVSI-positive vessels per H&E-stained slide. Using a predefined threshold for clinical relevance, the risk of pelvic lymph node recurrence risk was calculated (Kaplan-Meier method, with Cox regression) using a stepwise adjustment for the number of LVSI-positive vessels. This analysis was then repeated in the Danish Gynecological Cancer Database (DGCD) cohort. Among patients in PORTEC-1 and PORTEC-2 trials who did not receive external beam radiotherapy, the 5-yr pelvic lymph node recurrence risk was 3.3%, 6.7% (P=0.51), and 26.3% (P<0.001), respectively when 0, 1 to 3, or ≥4 vessels had LVSI involvement; similar results were obtained for the DGCD cohort. Furthermore, both the average number of tumor cells in the largest embolus and the number of LVSI-positive H&E slides differed significantly between focal LVSI and substantial LVSI. On the basis of these results, we propose a numeric threshold (≥4 LVSI-involved vessels in at least one H&E slide) for defining clinically relevant LVSI in EC, thereby adding supportive data to the semiquantitative approach. This will help guide gynecologic pathologists to differentiate between focal and substantial LVSI, especially in borderline cases.

Uterine Endometrial Stromal Tumors With Limited Infiltration and Unusual Patterns of Smooth Muscle/Leiomyomatous Differentiation: A Report of 2 Cases Recapitulating Leiomyoma Variants

Low-grade Endometrial Stromal Sarcoma With Sex Cord-like Differentiation and PHF1-JAZF1 Fusion With Deletions: A Diagnostic Pitfall of JAZF1 FISH

The molecular knowledge of endometrial stromal neoplasms has been rapidly increasing and is considered complementary to morphologic and immunohistochemical findings for better categorization of these tumors. The most common molecular alteration observed in low-grade endometrial stromal sarcomas is the JAZF1-SUZ12 fusion, whereas, low-grade endometrial stromal sarcoma with sex cord-like differentiation have been shown more commonly to have fusions involving PHF1. Herein, we present a low-grade endometrial stromal sarcoma with sex cord-like differentiation with a fluorescence in situ hybridization showing the apparent loss of one copy of JAZF1 5′ and 3′ signals, rather than the expected “break-apart” pattern seen in the setting of a JAZF1 fusion. The case was then further evaluated by chromosome microarray and RNA fusion analysis. Overall, the molecular findings supported a PHF1-JAZF1 fusion with deletions right before and after the JAZF1 locus, impairing probe binding and resulting in the unusual “deletion” pattern observed in the JAZF1 fluorescence in situ hybridization, which would not intuitively suggest a fusion involving JAZF1. This case illustrates the importance of integration of morphological and molecular findings as well as the limitations of fluorescence in situ hybridization in detecting fusions, particularly in the setting of more complex chromosomal alterations even though the fusion partners are well-known.

PD-L1 Expression in Mismatch Repair-deficient Endometrial Carcinoma and Tumor-associated Immune Cells: Differences Between MLH1 Methylated and Nonmethylated Subgroups

Mismatch repair (MMR)-deficient endometrial carcinomas show increased programmed cell death-ligand 1 (PD-L1) expression compared with MMR-intact endometrial carcinomas, but there are limited data regarding PD-L1 expression between sporadic and inherited carcinomas exhibiting MMR loss. Most of the studies investigating PD-L1 expression in endometrial carcinoma have used tissue microarrays and did not examine all tumor blocks. In this study, we analyzed the expression of PD-L1 in resection specimens of 176 consecutive endometrial carcinomas using all tumor blocks; we compared PD-L1 expression in MMR-deficient endometrial carcinomas, including the MLH1 and PMS2-loss subgroup, and the other MMR-loss subgroups (MSH2 and MSH6, isolated PMS2, and isolated MSH6), with the MMR-intact subgroup. MLH1 methylation was performed in tumors with MLH1 and PMS2 loss. Tumor cell (TC) and tumor-associated immune cell (IC) PD-L1 positivity with a 1% cutoff was observed in 21% (n=37) and 66.5% (n=117) of cases, respectively, and with a 5% cutoff in 5.1% (n=9) and 39.8% (n=70) of cases, respectively. MMR protein deficiency was a statistically significant parameter associated with IC PD-L1 positivity, with 1% and 5% cutoffs on multivariate analysis [odds ratio (OR)=5.236, 95% confidence interval (CI)=2.075-13.211, P=0.001, and OR=3.702, 95% CI=1.759-7.791, P=0.001, respectively]. The multivariate analysis showed that IC PD-L1 positivity, using both 1% and 5% cutoffs, was significantly associated with the MLH1 and PMS2 loss compared with the MMR protein-intact subgroup (MLH1 and PMS2 loss for 1% cutoff: OR=5.104, 95% CI=1.876–13.881, P=0.001, and for 5% cutoff: OR=3.322, 95% CI=1.540–7.166, P=0.002). Squamous differentiation was an independent predictor for TC PD-L1 positivity, with a 5% cutoff (OR=6.102, 95% CI=1.280–10.096, P=0.026). Larger tumor size was an independent predictive factor for IC PD-L1 positivity with a 1% cutoff (OR=6.757, 95% CI=1.569–29.109, P=0.010). Overall, 48 (92.3%) of 52 MLH1 methylated tumors showed IC PD-L1 positivity with 1% cutoff, and 34 (65.4%) of 52 MLH1 methylated tumors showed IC PD-L1 positivity with 5% cutoff. Our results show a higher rate of IC PD-L1 positivity than in previous studies. This is likely due in part to the use of all tumor blocks. MLH1 and PMS2 loss was an independent predictive factor for IC PD-L1 positivity, with both 1% and 5% cutoffs. Using univariate analysis, we observed decreased disease-free survival for IC PD-L1 positivity ≥5%. Our study results should now be tested and proven in larger cohorts, with longer follow-up data.

Endometrial Carcinoma as the Presenting Malignancy in a Teenager With a Pathogenic TP53 Germline Mutation: A Case Report and Literature Review

Patients with germline TP53 mutations are characterized by the occurrence of multiple early-onset malignancies. The characteristic syndrome is Li-Fraumeni syndrome (OMIM # 151623), an autosomal dominant disorder typified by premenopausal breast carcinoma, adrenal cortical tumors, bone and soft tissue sarcomas, leukemias, and tumors of the brain and spinal cord. Gynecologic malignancies are uncommonly reported in families harboring TP53 mutations, and the predominant tumor type reported is ovarian. Uterine carcinoma has been reported only a handful of times in patients with germline TP53 mutations, none as a presenting tumor in a teenager. We report on an 18-year-old patient who presented with grade 3, high-stage endometrioid endometrial carcinoma. Sequencing detected a single-nucleotide substitution in the TP53 gene (NM_000546.6:c.818G>A), encoding the missense substitution p.Arg273His (R273H) in both the tumor and normal tissue, consistent with a germline mutation. We discuss the biology of the TP53 gene and p53 protein, with emphasis on the R273H mutation. We also review the literature on endometrial carcinoma in patients with germline TP53 mutations.

Folate Receptor Alpha Is Preferentially Expressed in the Carcinoma Component of Endometrial Carcinosarcomas: A Potential Target for Adjuvant Therapy

Carcinosarcomas (CSs) of the endometrium are biphasic malignancies, composed of high-grade carcinomatous and sarcomatous components. Surgical stage and pathologic characteristics are the most important prognostic findings, with a 5-yr survival of 15% to 30% in advance stage disease. Folate receptor alpha (FRA) overexpression has been observed in endometrial carcinomas and not yet studied in CSs. This study evaluates semiquantitative expression of FRA in both carcinomatous and sarcomatous components of CSs on whole tissue sections. Immunohistochemistry for FRA expression was performed and extent and intensity of staining were recorded for each case for both histologic components. A total of 46 cases were stained for FRA. The majority of these (40/46, 87%) showed FRA staining at variable intensity in the carcinomatous component, stronger in serous carcinomas and high-grade endometrioid, while only a small subset of tumors demonstrated weak staining in the sarcomatous component (2/46, 4.35%). CS is known to be associated with poor prognosis and adjuvant therapy is recommended even in low stage disease. Serous and high-grade endometrioid carcinomas are the most common carcinomatous components of CSs and are known to show consistently high FRA expression. Folate plays a role in tumor cell migration and loss of cellular adhesion, which are key steps in epithelial-mesenchymal transition, the process by which CS develops from carcinoma cells. Our study shows expression of FRA in the carcinomatous component of almost all CS cases (87%), further favoring FRA as a target for adjuvant treatment. While expression of FRA in the sarcomatous component was rarely observed, the carcinomatous component being associated with metastatic potential underscores the importance of anti-FRA therapy for systemic disease control.

HER2 Expression in Endometrial Cancers Diagnosed as Clear Cell Carcinoma

There is increasing evidence that many endometrial cancers (EC) diagnosed as clear cell carcinoma (CCC) have substantial overlap with both serous carcinoma (SC) and endometrioid carcinoma (EmC), not only in terms of morphology and immunophenotype but also by molecular characterization. Now with use of HER2-based therapy in SC, a CCC diagnosis in serous-like tumors has the potential to exclude patients from receiving beneficial therapy. To assess HER2 in CCC in relation to other characteristics, a tissue microarray of archived CCC, EmC, and SC was stained for HER2 alongside a battery of immunostains used in EC. Cases with equivocal HER2 IHC were also assessed by in situ hybridization. HER2 status was assessed in 229 cases (23 CCC, 74 SC, 132 EmC). HER2 was positive in 48% of cases diagnosed as CCC, 19% of SC, and 0% of EmC. Rigorous morphologic and immunophenotypic review by 5 gynecologic pathologists revealed diagnostic disagreement in 8/11 HER2+ cases diagnosed as CCC, with SC as the other major diagnostic consideration. All HER2+ (n=25) cases were MMR-intact and most HER2+ EC had aberrant p53 staining (22/25, 88%); the 3 cases with a wild type pattern for p53 (12%) were all negative for ER. Based on these findings, patients with a diagnosis of CCC should be included in future clinical trials of HER2-targeted therapy. Moreover, given the diagnostic difficulty surrounding CCC, immunohistochemistry-based algorithms that include aberrant p53 and/or the absence of ER expression may provide a more objective means of establishing eligibility criteria than is currently possible using traditional histologic classification.

FIGO Grade 3 Endometrioid Adenocarcinomas With Diffusely Aberrant β-Catenin Expression: An Aggressive Subset Resembling Cutaneous Pilomatrix Carcinomas

Uterine endometrioid adenocarcinomas are known for their morphologic plasticity. In addition to a multiplicity of metaplasias, uterine endometrioid adenocarcinomas may also undergo high-grade divergent differentiation in the form of high-grade neuroendocrine carcinoma, neuroectodermal differentiation or carcinosarcoma; others may dedifferentiate completely. Here we describe 5 cases of uterine endometrioid adenocarcinomas with high-grade divergent differentiation showing a striking morphologic and immunophenotypic resemblance to cutaneous pilomatrix carcinoma. Specifically, the high-grade component in all cases exhibited solid, basaloid morphology with conspicuous tumor cell necrosis and the presence of shadow cells, accompanied by diffusely aberrant (nuclear and cytoplasmic) β-catenin expression as well as variably diffuse CDX2 expression. In addition, the high-grade component in all cases showed loss of ER and PAX8 expression, retained MMR expression, wild-type p53 expression, patchy p16 expression, and diffusely positive cytokeratin expression (AE1/AE3 and CK7); at least focal neuroendocrine marker expression was present in all cases. CK20 was negative in all cases, with the exception of very focal staining in a single case (2% of tumor cells). All 5 of our tumors had at least a focal conventional FIGO grade 1 component. In all 4 cases tested, the low-grade component retained both PAX8 and ER expression and had, at best, focally aberrant β-catenin expression. Two of our cases had molecular analysis performed and both harbored mutations in exon 3 of CTNNB1 as expected; molecular analysis also revealed that both cases lacked POLE or TP53 mutations and showed no microsatellite instability. The tumors in this series were uniformly aggressive. Four of the 5 patients in our cohort had available follow-up information; of these, 3/4 died of their disease within 14 mo of diagnosis and the fourth patient had distant metastatic disease at presentation and is alive with disease 1 mo following diagnosis. The 1 patient without follow-up information also had distant metastatic disease at presentation and was lost to follow-up 17 mo later. The cases described in this series (1) represent a highly aggressive CTNNB1-mutated subset of the “no specific molecular profile” category of endometrioid adenocarcinomas; (2) illustrate a form of high-grade divergent differentiation resembling cutaneous pilomatrix carcinoma already described in carcinomas at other anatomic sites; and (3) underscore the difficulty in recognizing this phenotype at distant metastatic sites, which are frequent even at the time of presentation, given the consistent loss of ER and PAX8 expression and concurrent CDX2 expression.

SATB2 Expression in Uterine Sarcoma: A Multicenter Retrospective Study

Uterine sarcomas represent a clinical challenge because of their difficult diagnosis and the poor prognosis of certain subtypes. The aim of this study was to evaluate the expression of the special AT-rich sequence-binding protein 2 (SATB2) in endometrial stromal sarcoma (ESS) and other types of uterine sarcoma by immunohistochemistry. We studied the expression of SATB2 on 71 full tissue sections of endometrial stromal nodule, low-grade ESS, uterine leiomyomas and leiomyosarcoma, undifferentiated uterine sarcoma, adenosarcoma, and carcinosarcoma samples. Nuclear SATB2 expression was then evaluated in an extended sample set using a tissue microarray, including 78 additional uterine tumor samples. Overall, with a cut-off of ≥10% of tumor cell staining as positive, the nuclear SATB2 score was negative in all endometrial stromal nodule samples (n=10) and positive in 83% of low-grade ESS samples (n=29/35), 40% of undifferentiated uterine sarcoma (n=4/10), 13% of leiomyosarcoma (n=2/16), 14% of adenosarcoma (n=3/22), and 8% carcinosarcoma (n=2/25) samples. Furthermore, in ESS patients, direct comparison of nuclear SATB2 scores with clinicopathologic parameters and other reported biomarkers such as progesterone receptor and estrogen receptor showed that nuclear SATB2 was associated with PR expression and a decreased risk of disease-specific death (odds ratio=0.06, 95% confidence interval=0.04–0.81, P=0.04). Our data suggest that SATB2 could be a marker with relative sensitivity (83%) for distinguishing between endometrial stromal nodule and ESS with potential prognostic value.

Endometrial Adenocarcinomas With No Specific Molecular Profile: Morphologic Features and Molecular Alterations of “Copy-number Low” Tumors

The study evaluated morphologic patterns, mutational profiles, and β-catenin immunohistochemistry (IHC) in copy-number low (CNL) endometrial adenocarcinomas (EAs). CNL EAs (n=19) with next-generation or whole genome sequencing results and available tissue for IHC were identified from our institutional database. Clinical data and histologic slides were reviewed. IHC for β-catenin was performed and correlated with mutation status. Images of digital slides of CNL EAs from The Cancer Genome Atlas (TCGA) database (n=90) were blindly reviewed by 4 pathologists, and morphology was correlated with mutation status. Categorical variables were analyzed using the Fisher exact test, and agreement was assessed using Fleiss κ. CTNNB1 mutations were present in 63% (12/19) of CNL EAs. β-catenin nuclear localization was present in 83% of CTNNB1-mutated tumors (10/12) and in 0% (0/7) of CTNNB1-wildtype tumors (sensitivity 0.83, specificity 1.00). Squamous differentiation (SD) was present in 47% (9/19) and was more often observed in CTNNB1-mutated tumors (P=0.02). Mucinous differentiation (MD) was associated with KRAS mutations (P<0.01). Digital image review of TCGA CNL EAs revealed that pathologist agreement on SD was strong (κ=0.82), whereas agreement on MD was weak (κ=0.48). Pathologists identified SD in 22% (20/90), which was significantly associated with the presence of CTNNB1 mutations (P<0.01). CNL EAs demonstrate several morphologies with divergent molecular profiles. SD was significantly associated with CTNNB1 mutations and nuclear localization of β-catenin in these tumors. Nuclear expression of β-catenin is a sensitive and specific IHC marker for CTNNB1 mutations in CNL EAs. CNL EAs with KRAS mutations often displayed MD.

The Many Uses of p53 Immunohistochemistry in Gynecological Pathology: Proceedings of the ISGyP Companion Society Session at the 2020 USCAP Annual9 Meeting

Ancillary immunohistochemistry (IHC) has become a reliable adjunct for subclassification of gynecological neoplasms. An important recent development was optimization and validation of p53 IHC, where 3 abnormal IHC patterns (nuclear overexpression, complete absence, cytoplasmic) were shown to predict underlying TP53 mutations with high accuracy in ovarian carcinomas. p53 IHC now helps in distinguishing high-grade serous from low-grade serous carcinomas. Thereafter, the new interpretation of p53 IHC was quickly adapted for other purposes and similar accuracies were shown in endometrial carcinomas, vulvar squamous cell carcinomas, and ovarian mucinous tumors. However, it required further refinement of the p53 IHC interpretation criteria for each tumor site. A proportion of endometrial endometrioid carcinomas shows an ultramutated or hypermutated genotype due to underlying POLE mutations or mismatch repair deficiency sometimes causing subclonal TP53 mutations, and their distribution can be visualized by p53 IHC. Squamous cell carcinomas and ovarian mucinous tumors show a phenomenon called terminal differentiation where basal cells demonstrate an abnormal pattern of p53 IHC but apical cells do not despite an underlying TP53 mutation. High-grade progression of adult granulosa cell tumors due to a subclonal TP53 mutation has been recently described. Another use of p53 IHC is triaging gynecological sarcomas for molecular testing based on the assumption that TP53-mutated gynecological sarcomas do not harbor cancer driving translocations. Therefore, familiarity with interpretation of p53 IHC is becoming increasingly important for the practicing gynecological pathologist. Furthermore, local optimization of the p53 IHC assay using validated protocols including appropriate low expressing control tissues (eg, tonsil) is vital in order to achieve high diagnostic accuracy, especially for abnormal staining patterns such as complete absence or cytoplasmic, and interlaboratory concordance. p53 IHC is a reliable diagnostic adjunct for histotyping and molecular subtyping of ovarian and endometrial carcinomas, and it paves the way for large-scale studies to validate the prognostic value of p53 IHC in several gynecological tumor types. The technical advances, validated interpretation criteria, and its growing versatility in identifying high-risk neoplasms paired with its widespread availability in pathology departments make p53 IHC perhaps the single most useful IHC stain in gynecological pathology.

HER2 Testing and Reporting in Endometrial Serous Carcinoma: Practical Recommendations for HER2 Immunohistochemistry and Fluorescent In Situ Hybridization: Proceedings of the ISGyP Companion Society Session at the 2020 USCAP Annual Meeting

Anti-HER2 therapy has recently emerged as an effective targeted treatment approach for patients with advanced stage and recurrent endometrial serous carcinoma, resulting in significantly prolonged progression-free and overall survival when combined with the standard chemotherapy regimen. Consequently, there is an increasing clinical demand in pathology laboratories for HER2 testing of these tumors. This article provides an overview of the unique characteristics of HER2 protein expression and gene amplification in endometrial serous carcinoma and summarizes the HER2 scoring criteria used for patient enrollment in the recent clinical trial. Following the experience of guideline-development in other tumor types, the trial criteria should serve as the basis for future endometrial carcinoma-specific HER2 testing and scoring recommendations, to ensure therapeutic response in new patient cohorts. Thus, based on the clinical trial, the author proposes a specific HER2 testing algorithm for endometrial serous carcinoma to guide the current clinical practice. Future studies are necessary to refine and adjust these criteria to allow for appropriate triaging of patients and maximize the clinical benefit from HER2-targeted therapy.

POLE, MMR, and MSI Testing in Endometrial Cancer: Proceedings of the ISGyP Companion Society Session at the USCAP 2020 Annual Meeting

Subclassification of endometrial carcinoma (EC) based on morphologic features alone has been shown to have suboptimal reproducibility, both in regard to biopsy versus hysterectomy findings, as well as interobserver agreement. This restricts the role of morphologic classification of EC as a tool for risk prediction and therefore treatment planning. A diagnostic algorithm based on The Cancer Genome Atlas (TCGA) classification of EC holds promise for improving accuracy in risk prediction. This classifies EC into 4 groups: those harbouring mutations in the exonuclease domain of DNA polymerase epsilon, POLE (POLEmut), those showing a mismatch repair defect, those showing mutations in TP53 (p53abn) and a heterogenous group showing none of these 3 abnormalities (currently termed no specific molecular profile). These groups can be accurately and reproducibly diagnosed on biopsy samples using a limited panel of tests, namely immunohistochemistry for mismatch repair proteins and p53, and testing for POLE exonuclease domain pathogenic variants. In this article we briefly review the biology, testing and interpretation of POLE and mismatch repair defects in EC.

MLH1/PMS2-deficient Endometrial Carcinomas in a Universally Screened Population: MLH1 Hypermethylation and Germline Mutation Status

MLH1/PMS2 loss due to epigenetic hypermethylation of the MLH1 promoter is the most common cause of mismatch repair deficiency in endometrial carcinoma, and typically provides reassurance against an associated germline mutation. To further characterize the genetic features of MLH1/PMS2-deficient endometrial cancers, the departmental database was searched for cases with dual MLH1/PMS2 loss and retained MSH2/6 expression which underwent MLH1 hypermethylation testing. Genetic testing results were obtained when available. One hundred seventeen endometrial cancers met inclusion criteria: 100 (85%) were MLH1-hypermethylated, 3 (3%) were low-level/borderline, 7 (6%) were nonmethylated, and 7 (6%) were insufficient for testing. Sixteen cases (12 MLH1-hypermethylated, 3 nonmethylated, and 1 insufficient for testing) underwent germline testing, 6 of which (37.5%) demonstrated germline variants of unknown significance (VUS) (MSH6, PMS2, POLD1, BRIP1, RAD51D, CHEK2) but no known deleterious mutations. Notably, however, the patients harboring the MSH6 and PMS2 germline VUS had clinical features concerning for Lynch syndrome. One nonmethylated, germline-normal case underwent somatic tumor testing, and demonstrated a somatic MLH1 mutation. In summary, MLH1-hypermethylation accounts for the vast majority of MLH1/PMS2-deficient cancers in a universally screened population, although MLH1 somatic and germline mutations can occur. Occasionally, patients with MLH1-hypermethlated tumors also bear germline VUS in other mismatch repair genes as well as genes implicated in other hereditary cancer syndromes, but their clinical relevance is unclear. Family and personal cancer histories must always be evaluated to determine the need for germline testing in women with loss of MLH1/PMS2, even in the setting of hypermethylation.

Clinicopathologic Association and Prognostic Value of MELF Pattern in Invasive Endocervical Adenocarcinoma (ECA) as Classified by IECC

Microcystic, elongated, and fragmented (MELF) pattern of myometrial invasion is correlated with lymphovascular invasion (LVI) and lymph node metastases in uterine endometrioid carcinoma but has not been described in endocervical adenocarcinoma (ECA). A total of 457 ECAs were collected, and clinical/morphologic parameters correlated with follow-up data. Potential associations between MELF pattern and age, human papillomavirus status, tumor size/grade, LVI, lymph node metastases, Silva pattern were analyzed. Statistical analyses of overall survival (OS), disease-free survival, progression-free survival (PFS) were conducted using Kaplan-Meier analysis, and compared using the Log-rank test. Of 292 ECAs analyzed, 94 (32.19%) showed MELF invasion pattern (MELF-positive). Significant statistical correlation was found between MELF-positive and tumor size (P=0.0017), LVI (P=0.007), Silva pattern (P=0.0005); age, human papillomavirus status, tumor grade, lymph node metastases did not correlate. Fifty-five of 292 patients recurred (18.83%): 18/94 (19.14%) MELF-positive, 37/198 (18.68%) MELF-negative. PFS in MELF-positive: 77.2% and 64.5% at 5 and 10 yr, respectively; PFS in MELF-negative: 82% and 68.5% at 5 and 10 yr, respectively. On multivariate analysis for PFS and other prognostic parameters, only LVI was statistically significant (P=0.001). OS in MELF-positive was 86% and 74.1% at 5 and 10 yr, respectively; OS in MELF-negative, was 89.7% and 86% at 5 and 10 yr, respectively. Median survival was worse in MELF-positive (199.8 mo) versus MELF-negative (226.1 mo); this was not statistically significant. On multivariate analysis for OS and other prognostic parameters, only tumor stage was statistically significant (P=0.002). In ECAs, MELF is not independently associated with survival. Pathologic characteristics of MELF-positive (size, LVI, Silva pattern) versus MELF-negative tumors differ significantly.