Lawrence Hsu Lin

Isolated morular squamous metaplasia in endometrial biopsies and curettings: is there a role for repeated sampling?

Aims Endometrial atypical hyperplasia and low‐grade endometrioid carcinoma are often associated with morular squamous metaplasia. Limited evidence suggests that the finding of isolated morular squamous metaplasia without concomitant glandular neoplasia in biopsies is associated with a 6.5% risk of endometrial cancer in subsequent samples and warrants close follow‐up. However, its prognostic value has not been clearly determined. Methods and results The Massachusetts General Hospital pathology database was queried to identify endometrial samples with a diagnosis of ‘adenoacanthosis’, ‘morular metaplasia’, ‘squamous metaplasia’ or ‘morular squamous metaplasia’ between 2012 and 2024. Cases associated with endometrioid carcinoma, non‐atypical or atypical hyperplasia, atypical polypoid adenomyoma and gland crowding insufficient for diagnosis of atypical hyperplasia were excluded. Clinicopathologic data were collected. Outcomes were categorized as regression, persistence and progression to carcinoma. Of 32,800 endometrial samples reported during the study period, isolated morular squamous metaplasia was diagnosed in 57 (0.17%), including 42 (73.7%) biopsies and 15 (26.3%) curettings. The median patient age was 45 (21–70) years. Histologic follow‐up (at least one follow‐up sample) was available in 22 patients (median 30 months, 1–120) and included endometrial biopsy, curettage or hysterectomy. Of these 22 patients, a single follow‐up biopsy was performed in 9 (40.9%), a single curettage in 1 (4.5%), hysterectomy in 6 (27.3%), a single biopsy followed by hysterectomy in 2 (9.1%), multiple biopsies in 3 (13.6%) and a curettage followed by multiple biopsies and hysterectomy in 1 (4.5%). The median number of follow‐up samples was 2 (2–9) per patient. Histologically, the follow‐up samples were unremarkable (regression) in most patients (19/22, 86.4%), 2 (9.1%, aged 49 and 57 years) were diagnosed with grade 1 endometrioid carcinoma in subsequent hysterectomies, and 1 (4.5%, age 62) had persistent squamous morular metaplasia (follow‐up 69 months). In 15 patients with clinical follow‐up but no further pathology sampling, none had clinical symptoms at their last visit (100% clinical regression). Thus, the overall rate of endometrioid carcinoma was 5.4% (2/37). Conclusions Isolated squamous morular metaplasia without associated glandular neoplasia is a rare finding, reported only in 0.17% of endometrial samples. The risk of subsequent endometrioid neoplasia appears to be low (5.4%), although the possibility of undersampled atypical hyperplasia/endometrioid carcinoma cannot be completely ruled out without additional sampling. Persistent squamous morular metaplasia is relatively uncommon (4.5%) and may not lead to the subsequent diagnosis of endometrial cancer, questioning the utility of numerous repeat samplings in patients without progression after one repeat sample.

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.

Atypical Placental Site Nodule and Related Lesions

Placental site nodule (PSN) and atypical placental site nodule (APSN) are chorionic-type intermediate trophoblastic lesions, the latter characterized by worrisome histologic characteristics and risk for subsequent trophoblastic neoplasia, mainly epithelioid trophoblastic tumor (ETT). There is no consensus or evidence-based criteria on which and how many features are needed for APSN diagnosis. We assessed interobserver reproducibility of APSN, PSN, and ETT. Five expert pathologists evaluated representative whole slide images (1 hematoxylin-and-eosin and 1 Ki-67/AE1-AE3 immunohistochemical stain) of 50 cases with APSN, PSN, or ETT index diagnosis and recorded independently diagnostic impressions and worrisome histologic characteristics (extensive lesional tissue, severe nuclear atypia, hypercellularity, mitotic activity, irregular borders, tumor necrosis, and Ki-67 index ≥5%). Diagnostic consensus was reached in 96% (agreement of ≥3 experts), and there was agreement with the index diagnosis in 75%. Overall, Fleiss’ kappa score (κ) was 0.46 (highest for PSN [κ=0.58] and lowest for APSN [κ=0.34]). Substantial agreement was reached in evaluating extensive lesional tissue (lesional tissue exceeding normal, κ=0.76) and Ki-67 in the entire lesion (intraclass correlation coefficient=0.62). Most other features showed moderate reproducibility. In cases with a higher degree of agreement, most APSN harbored 3 to 6 worrisome features, while most PSN had <2 and all ETTs had ≥6. In conclusion, APSN diagnosis is challenging, reflected by fair reproducibility among experts. However, agreement was reached in most instances, highlighting the beneficial role of consultation. Criteria refinement may increase reproducibility with the highest agreement of extensive lesional tissue and proliferation in the entire lesion with Ki-67/AE1-AE3. The presence of ≥3 worrisome features might be a reasonable threshold to avoid APSN overdiagnosis.

From morphology to methylome: epigenetic studies of Müllerian mesonephric‐like adenocarcinoma reveal similarities to cervical mesonephric adenocarcinoma†

AbstractMesonephric adenocarcinomas (MAs) and mesonephric‐like adenocarcinomas (MLAs) are rare, aggressive neoplasms that arise in the gynecologic tract and show overlapping morphologic, immunohistochemical, and molecular features. While MAs occur in the cervix and are thought to arise from mesonephric remnants, MLAs occur in the endometrium and ovary and are believed to originate from transdifferentiation of Müllerian lesions. Both MAs and MLAs show a variety of architectural patterns, exhibit frequent expression of GATA3 by immunohistochemistry, and harbor KRAS mutations. In a recent article published in The Journal of Pathology, Kommoss and colleagues used DNA methylation profiling to extend these similarities and showed that MLAs and MAs cluster together based on their epigenetic signatures and are epigenetically distinct from other Müllerian adenocarcinomas. They also showed that MLAs and MAs harbor a high number of global copy number alterations. This study provides evidence that MLAs more closely resemble MAs than Müllerian carcinomas on an epigenetic level. As a result, the authors argue that MLA should be renamed ‘mesonephric‐type adenocarcinoma.’ Further research is needed to establish the relationship between these two entities, their etiology, and pathogenesis. © 2024 The Pathological Society of Great Britain and Ireland.

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.

Claudin-18 and Mutation Surrogate Immunohistochemistry in Gastric-type Endocervical Lesions and their Differential Diagnoses

Gastric-type endocervical adenocarcinomas (GAS) are aggressive HPV-independent neoplasms with molecular alterations in TP53, STK11, CDKN2A, and SMAD4. Claudin-18 (CLDN18) has emerged as a useful marker to distinguish GAS from HPV-associated neoplasia. Its role in separating GAS from benign proliferations and exuberant endocervical glands is unknown. We studied the utility of immunohistochemistry for CLDN18, progesterone receptor (PR), and mutation surrogate stains (P53, STK11/LKB1, MTAP, SMAD4/DPC4) in 46 GAS, 12 benign gastric-type endocervical lesions, 54 benign Mullerian endocervical populations, and 11 HPV-associated endocervical adenocarcinomas. PD-L1 and HER2 immunostains were evaluated in GAS. Gastric-type lesions were more often positive for CLDN18 (100% benign, 78% GAS, most often well to moderately differentiated) compared to benign Mullerian endocervical specimens (all negative) and HPV-associated neoplasia (18%, always focal). Conversely, PR was negative in all gastric-type lesions and positive in 92% of benign Mullerian endocervical populations. GAS revealed aberrant/mutant expression of P53 in 35%, STK11/LKB1 in 25%, MTAP in 23%, and SMAD4/DPC4 in 9% of cases. Abnormal staining in at least one of these 4 mutation surrogate markers was present in 63% of GAS. HER2 score of 3+ was seen in 25% of GAS, and PD-L1 was positive in 37% based on a combined positive score. CLDN18 is a sensitive and highly specific marker of gastric-type benign and malignant endocervical lesions. Once a gastric-type phenotype is confirmed, mutation surrogate immunostains can be used to support a diagnosis of GAS. PD-L1 and HER2 expression is seen in a subset of GAS offering therapeutic options for this aggressive tumor.

Intratumoral budding is associated with poor clinical outcome in early‐stage clear cell carcinoma of ovary*

AimsClear cell carcinoma of ovary (CCC) is considered a high‐grade malignancy by default and the role of histological grading for assessing clinical outcome is not established. We aimed to evaluate histopathological features associated with clinical outcome in CCC patients.Methods and resultsSeventy‐six cases of CCC with available clinical follow‐up information were studied. Histopathological features, including tumour size, architectural patterns, nuclear atypia, mitotic activity, intratumoral and peritumoral inflammation, presence of endometriosis, peritumoral and intratumoral budding, were evaluated. Multivariate analysis was performed with logistic regression and Kaplan–Meier survival curves with the log‐rank test were used for survival analysis. Forty cases (53%) presented at stage I. Complete response to treatment was achieved in 65%, while 35% of patients had tumour recurrence or progression of disease despite treatment. At last follow‐up, 13% had died of disease, 20% were alive with disease and 67% had no evidence of disease. Higher stage (P = 0.0016) and presence of intratumoral budding (P = 0.0454) were independently associated with recurrence/disease progression. Advanced stage (P = 0.0011), presence of lymph node involvement (P = 0.0003), intratumoral budding (P = 0.0023) and peritumoral budding (P = 0.0334) were significantly associated with shorter survival. Intratumoral budding was significantly associated with recurrent/progressive disease (P = 0.0195) and also shorter survival (P = 0.0277) within the cohort of low‐stage (I/II) patients as well.ConclusionWe have shown that besides the classic prognostic factors of stage and lymph node status, the presence of tumour budding is associated with poorer outcome in patients with CCC. Specifically, evaluation of intratumoral budding may help to more clearly predict prognosis in patients with early‐stage disease.

Cervicovaginal cytology, HPV testing and vaginal flora in transmasculine persons receiving testosterone

AbstractBackgroundTestosterone is one of the strategies that transmasculine persons can elect in order to align physical traits to their gender identity. Previous studies have shown morphologic changes in the genital tract associated with testosterone. Here, we aim to evaluate cervicovaginal cytology specimens (Pap tests) and high‐risk HPV (HR‐HPV) testing from transmasculine individuals receiving testosterone.MethodsThis is a retrospective cohort of 61 transmasculine individuals receiving testosterone from 2013 to 2021. Cytologic diagnoses from 65 Pap tests were correlated with HPV status and histologic follow‐up and compared with the institutional data and a cohort of cisgender women with atrophic changes.ResultsThe median age was 28 years and median time of testosterone use was 3 years. Transmasculine persons showed significantly higher rates of HSIL (2%) and unsatisfactory (16%) when compared with the institutional data and atrophic cohort of cisgender women. After reviewing slides of 46 cases, additional findings were noted: atrophy was present in 87%, glycogenated cells were seen in 30%, and Lactobacilli were substantially decreased in 89%. Among 32 available HPV tests, 19% were positive for HR‐HPV and 81% were negative. On histologic follow‐up, all HR‐HPV‐positive cases with abnormal cytology showed HSIL, while none of the HPV‐negative cases revealed HSIL.ConclusionOur study cohort demonstrated a high percentage of abnormal Pap tests in transmasculine persons receiving testosterone. Testosterone seems to induce changes in squamous cells and shifts in vaginal flora. HR‐HPV testing can be a useful adjunct in the workup of abnormal Pap tests from transmasculine individuals.

Role of High-Risk HPV Testing in Papanicolaou Tests With Atypical Glandular Cells With and Without Concurrent Squamous Cell Abnormalities

Abstract Objectives Data on Papanicolaou (Pap) tests with atypical glandular cells (AGCs) with concurrent squamous cell abnormalities (AGC + Sq) are limited. We evaluated histologic outcomes and the role of high-risk human papillomavirus (HR-HPV) testing in this setting compared with AGCs without concurrent squamous cell abnormalities (AGC-alone). Methods This study used a retrospective cohort of patients with Pap test diagnoses of AGC + Sq and AGC-alone between October 2013 and August 2021. Results We included 287 Pap tests from 278 patients. The HR-HPV test was positive in 55% of AGC + Sq cases and 14% of AGC-alone cases (P < .0001). Most AGC + Sq cases displayed squamous lesions (41.5%) or were benign (41.5%) on histology, whereas AGC-alone cases were predominantly benign (72%) or extracervical neoplasms (18%). AGC + Sq cases showed higher rates of significant histologic lesions (P = .0001), which were associated with positive HR-HPV status (P = .0012). In AGC-alone cases, HR-HPV status was associated with significant histology only in patients 50 years of age or younger. In both groups, 20% or more of HR-HPV–negative patients harbored significant lesions. Conclusions AGC + Sq represents a distinct group of patients. HR-HPV testing and patient age provide useful information in the evaluation of AGC, but triage based on HR-HPV testing is not recommended because of the potential for missing significant lesions.