Angela Santoro

Interobserver Agreement in Immunohistochemical Evaluation of Folate Receptor Alpha (FRα) in Ovarian Cancer: A Multicentre Study

Folate receptor alpha (FRα) is a high-affinity folate transporter overexpressed in various epithelial malignancies, particularly high-grade serous ovarian carcinoma. Given its restricted expression in normal tissues and accessibility in tumors, FRα is an emerging therapeutic target. Immunohistochemistry (IHC) is the standard method for FRα assessment; however, interpretation is semi-quantitative and prone to interobserver variability. This study aimed to evaluate interobserver agreement among 12 pathologists in the IHC assessment of FRα in ovarian cancer, focusing on internal control adequacy, staining intensity, and the percentage of FRα-positive tumor cells. Thirty-seven high-grade serous ovarian carcinoma cases were stained using the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay. A reference panel of four expert pathologists established consensus diagnoses. Twelve pathologists independently assessed the slides, recording internal control adequacy, staining intensity (positive vs. negative), and percentage of FRα-positive tumor cells. Interobserver agreement was measured using Fleiss’ kappa and intraclass correlation coefficient (ICC). Agreement on internal control adequacy was almost perfect (κ = 0.84). Substantial agreement was observed for staining intensity (κ = 0.76), while percentage estimation showed almost perfect concordance (ICC = 0.89). Discrepancies were primarily confined to borderline cases (65–85% positivity) and tumors with intermediate staining, reflecting interpretive challenges near clinical decision thresholds. Pathologists demonstrated high reproducibility in FRα IHC assessment, particularly in estimating percentage positivity and control adequacy. These findings support the clinical utility of FRα IHC but underscore the need for standardized scoring criteria and potential integration of digital tools to enhance consistency, especially in borderline cases.

Focal lymphovascular space invasion: Friend or foe? A large retrospective analysis on stage I endometrioid endometrial carcinomas

Literature is inconsistent with respect to clinical value of lymphovascular space invasion (LVSI) semiquantitative assessment. We aim to investigate the prognostic role of LVSI extent in stage I endometrioid endometrial carcinomas (ECs) classified by immunohistochemistry (IHC) analysis. Patients with stage I endometrioid EC undergone primary surgery were retrospectively included. Following World Health Organization definition for LVSI pathologic evaluation, subjects were divided into: LVSI-negative; LVSI-focal; LVSI-substantial. An IHC-based model was utilized to classify patients into: p53-aberrant (p53abn); mismatch repair deficient (MMRd); mismatch repair proficient with positive estrogen receptors (MMRp-ERpos); and mismatch repair proficient with negative estrogen receptors (MMRp-ERneg). 2091 subjects were included and divided into: 78.0 % (n:1631) LVSI-negative, 10.6 % (n:221) LVSI-focal, and 11.4 % (n:239) LVSI-substantial. Presence of LVSI (any extent) was associated with older age, larger tumor size and deeper myometrial infiltration. Patients with LVSI-substantial presented with higher incidence of grade 3 tumors, p53abn and MMRd status. Conversely, most LVSI-negative and LVSI-focal cases were MMRp-ERpos. At multivariable regression, LVSI-substantial was independently associated with reduced 5-year disease-free survival (DFS) and overall-survival (OS). LVSI-negative and LVSI-focal groups had similar DFS (p = 0.42) and OS (p = 0.09), whereas comparison with LVSI-substantial demonstrated significantly poorer outcomes for patients with substantial invasion. These findings were confirmed in sub-analyses of cases with grade 1-2 endometrioid and myometrial infiltration, and in the MMRp-ERpos cohort. In stage I endometrioid ECs, LVSI-focal was not associated with reduced oncologic outcomes compared to LVSI-negative. In contrast, LVSI-substantial was associated with aggressive clinicopathologic and molecular features and behaved as an independent prognostic factor for reduced survival. Our results were further confirmed in two low-risk EC settings: grade 1-2 with myometrial infiltration, and the MMRp-ERpos group.

Comprehensive genomic profiling and clinico-pathologic characterization of primary ovarian leiomyosarcoma

Primary ovarian leiomyosarcomas are exceptionally rare, accounting for less than 0.1% of ovarian malignancies. Their treatment strategies remain poorly defined, and data on comprehensive genomic profiling are lacking. This study aims to characterize the pathological features and genomic landscape of primary ovarian leiomyosarcoma, highlighting similarities with uterine leiomyosarcomas based on available literature. We retrospectively analyzed 7 histologically confirmed cases of primary ovarian leiomyosarcoma diagnosed between 2013 and 2023 at a tertiary referral center. Clinical data, histopathological findings, and immunohistochemical profiles were reviewed. Genomic profiling was performed using the TruSight Oncology 500 assay, targeting 523 cancer-related genes. Only oncogenic or likely oncogenic alterations (Tier classification system I-II) were considered. All patients had International Federation of Gynecology and Obstetrics stage IA disease and underwent radical surgery. Two patients experienced pelvic recurrence; both showed increased Ki-67 and complete loss of estrogen and progesterone receptors in the relapsed tumors. Histologically, tumors exhibited spindle or epithelioid morphology with variable atypia and mitotic indices. Genomic profiling revealed a high prevalence of TP53 (71%) and PTEN (57%) alterations. Additional copy number alterations were identified in homologous recombination repair genes (BRCA2, CHEK1/2, and ATM), fibroblast growth factor (FGF) family members (FGF7/9/14), and platelet-derived growth factor receptor beta. Tumor mutational burden was low to medium in all cases, and microsatellite status was stable. Primary ovarian leiomyosarcomas exhibit a complex genomic landscape marked by genomic instability, sharing key alterations with uterine leiomyosarcomas. TP53 and PTEN mutations may play a central role in their pathogenesis. This first genomic profiling analysis of ovarian leiomyosarcomas provides a basis for further research and potential targeted therapeutic approaches in this rare malignancy.

A Case Report to Reflect on the Origins of MMRd Mesonephric-like Ovarian Adenocarcinoma: Can It Be Defined as a Mϋllerian Neoplasm?

Mesonephric-like adenocarcinoma (MLA) of ovaries is a new and rare neoplastic entity, recently classified by the World Health Organization. Its morphological and immunohistochemical profile is similar to primitive cervical mesonephric adenocarcinoma, but its origin has not been determined yet. Some authors believe that this neoplasm originates from Wolffian remnants in the ovarian hilum, while others suggest an origin from the Mϋllerian epithelium, followed by a mesonephric trans-differentiation. Starting from a recently diagnosed mismatch repair-deficient ovarian MLA, we try to further develop this line of research. A detailed molecular analysis of the studied tumor helps clarify our ideas. In fact, the typical KRAS mutation was not present. We found mutations in numerous other genes, which are rarely described in the literature or are already described in the endometrioid histotype. We reached some interesting conclusions, which, if supported by future studies, will clarify the true nature of these tumors, allowing for better stratification and a better therapeutic framework.

Folate Receptor Alpha in Advanced Epithelial Ovarian Cancer: Diagnostic Role and Therapeutic Implications of a Clinically Validated Biomarker

Folate receptor alpha (FRα), a glycosylphosphatidylinositol-anchored glycoprotein encoded by the FOLR1 gene, plays a crucial role in folate transport during cell growth and development. While minimally expressed in most normal adult tissues, FRα is frequently overexpressed in several epithelial malignancies, particularly in high-grade serous ovarian carcinoma. An immunohistochemical (IHC) evaluation of FRα expression using the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay is now approved as a companion diagnostic for selecting patients eligible for mirvetuximab soravtansine, an FRα-targeted antibody–drug conjugate. Clinical trials such as SORAYA and MIRASOL have demonstrated significant clinical benefit in platinum-resistant epithelial ovarian cancer patients with high FRα expression (≥75% of tumor cells with moderate to strong membrane staining). This review summarizes the biological significance of FRα in ovarian cancer progression, its predictive value for targeted therapy, and the technical aspects of IHC assessment, including scoring interpretation and pre-analytical variables. We also discuss heterogeneity in FRα expression across histological subtypes and tumor sites, as well as the impact of archival versus fresh tissue. Understanding FRα expression patterns across histologic subtypes and tissue samples is critical for optimizing clinical decision-making and expanding the role of FRα-targeted therapies in gynecologic oncology.

Rethinking certainty: a retrospective study on diagnostic revisions in gynecologic pathology

Mismatch Repair Deficiency as a Predictive and Prognostic Biomarker in Endometrial Cancer: A Review on Immunohistochemistry Staining Patterns and Clinical Implications

Among the four endometrial cancer (EC) TCGA molecular groups, the MSI/hypermutated group represents an important percentage of tumors (30%), including different histotypes, and generally confers an intermediate prognosis for affected women, also providing new immunotherapeutic strategies. Immunohistochemistry for MMR proteins (MLH1, MSH2, MSH6 and PMS2) has become the optimal diagnostic MSI surrogate worldwide. This review aims to provide state-of-the-art knowledge on MMR deficiency/MSI in EC and to clarify the pathological assessment, interpretation pitfalls and reporting of MMR status.

Are all mismatch repair deficient endometrial cancers created equal? A large, retrospective, tertiary center experience

One third of endometrial carcinomas (ECs) presents with mismatch repair deficiency (MMRd). Of these, 70 % are caused by somatic hypermethylation of MLH1 promoter; the remaining cases are determined by Lynch syndrome or double somatic inactivation of MMR genes. Although associated with good-intermediate prognosis, heterogeneity in treatment response and survival has been reported among MMRd ECs. We aim to investigate differences in pathologic aggressiveness and event-free survival (EFS) among three MMRd EC subtypes, classified by immunohistochemistry (IHC) and MLH1 methylation analysis. Subjects undergone surgical staging for EC were retrospectively included. IHC analysis was performed in all patients to assess MMR and p53 status. Methylation analysis was performed in MMRd patients with IHC-negative MLH1. The MMRd population was classified into: 1)MLH1-hypermethylated (MLH1-HyMet); 2)MLH1-unmethylated (MLH1-UnMet); 3)IHC-negative MSH2 and/or MSH6 or PMS2 alone (non-MLH1). Of 1171 patients undergoing surgical staging and IHC assessment, 362 (30.9 %) were classified as MMRd and included in the analysis. Among these, 59.7 % (n = 216) were MLH1-HyMet, 11 % (n = 40) MLH1-UnMet, and 29.3 % (n = 106) non-MLH1. Compared to MLH1-UnMet and non-MLH1, MLH1-HyMet was associated with older age, higher BMI, larger tumor size, deeper myometrial invasion, substantial lymphovascular space invasion, lower frequency of early-stage and low-risk disease. EFS was similar when comparing the MMRd subtypes, even after adjusting for stage and tumor histology. However, a trend of MLH1-HyMet toward poorer prognosis can be observed, particularly in the advanced/metastatic setting. MLH1-hypermethylated MMRd ECs display more aggressive clinicopathologic features compared to the other MMRd subgroups. However, although a suggestive trend toward poorer EFS was observed in the hypermethylated subset, particularly in the advanced setting, no significant differences in prognosis were detected among the MMRd subtypes.

The role of cytology in endometrial cancer: Diagnostic and clinical considerations from peritoneal/pelvic washings. Is it still a heated debate?

This editorial explores the diagnostic criteria and clinical implications of cytopathologic samples obtained from peritoneal/pelvic washings in patients with endometrial cancer.

Beyond the WHO 2020 Classification of Female Genital Tumors: Types of Endometrial Cancer: A Pathological and Molecular Focus on Challenging Rare Variants

Endometrial carcinoma is a heterogeneous group of malignancies characterized by distinct histopathological features and genetic underpinnings. The 2020 WHO classification has provided a comprehensive framework for the categorization of endometrial carcinoma. However, it has not fully addressed the spectrum of uncommon entities that are currently not recognized by the 2020 WHO and have only been described in the form of small case series and case reports. These neoplasms represent a real diagnostic challenge for pathologists; furthermore, their therapeutic management still remains controversial and information regarding tumor prognosis is very limited. This review aims to elucidate these lesser-known variants of endometrial carcinoma. We discuss the challenges of identifying these rare subtypes and the molecular alterations associated with them. Furthermore, we propose the need for expanded classification systems that include these variants to enhance clinical outcomes and research efforts. We believe that a better histological typing characterization of these entities may lead to more reproducible and accurate diagnoses and more personalized treatments. By raising awareness of these rare entities, we also hope to encourage further investigation and integration into clinical practice to improve patient care in endometrial carcinoma.

TCGA Molecular Prognostic Groups of Endometrial Carcinoma: Current Knowledge and Future Perspectives

The four TCGA-based molecular prognostic groups of endometrial carcinoma (EC), i.e., POLE-mutant, mismatch repair (MMR)-deficient, p53-abnormal, and “no specific molecular profile” (NSMP), have recently been integrated into ESGO-ESTRO-ESP guidelines. The POLE-mutant and MMR-deficient groups are associated with high mutational load, morphological heterogeneity, and inflammatory infiltration. These groups are frequent in high-grade endometrioid, undifferentiated/dedifferentiated, and mixed histotypes. POLE-mutant ECs show good prognosis and do not require adjuvant treatment, although the management of cases at stage >II is still undefined. MMR-deficient ECs show intermediate prognosis and are currently substratified based on clinicopathological variables, some of which might not have prognostic value. These groups may benefit from immunotherapy. P53-mutant ECs are typically high-grade and often morphologically ambiguous, accounting for virtually all serous ECs, most carcinosarcomas and mixed ECs, and half of clear-cell ECs. They show poor prognosis and are treated with chemoradiotherapy; a subset may benefit from HER2 inhibitors or PARP inhibitors. The NSMP group is the most frequent TCGA group; its prognosis is highly variable and affected by clinicopathological/molecular factors, most of which are still under evaluation. In conclusion, the TCGA classification has improved diagnosis, risk stratification, and management of EC. Further studies are needed to resolve the points of uncertainty that still exist.

Pathological features, immunoprofile and mismatch repair protein expression status in uterine endometrioid carcinoma: focus on MELF pattern of myoinvasion

Microcystic, elongated, and fragmented (MELF) pattern of myoinvasion has been related with increased risk of lympho-vascular space invasion (LVSI) and lymph node metastasis. We analysed a cohort of endometrioid endometrial carcinomas (EECs) to examine the relationships between the MELF pattern of invasion and the clinico-pathological and immunohistochemical features of EEC. 129 EECs were evaluated for the presence of MELF pattern and immunohistochemically tested for Mismatch repair (MMR) proteins, p16, p53 and beta-catenin. We observed 28 MELF + EECs and 101 MELF- EECs. LVSI was observed in 20 MELF + cases and in MELF- tumors. Lymph-node metastases were observed in 7 MELF + cases (2 macrometastases, 3 micrometastases and 2 ITCs). None of the MELF- cases showed micrometastases or ITCs, 18 cases had macrometastatic lymph-nodes. Statistical analysis showed that MELF + tumors carry an increased risk of developing nodal metastasis independent of tumor dimension and LVSI. Loss of MMR proteins expression was observed in 11 MELF + cases and 45 MELF- cases, respectively. Our data showed a higher frequency of immunohistochemical MLH1-PMS2 loss in MELF- pattern of invasion (32.67% of MELF- cases vs 21.43% of MELF + cases) but a higher prevalence of MSH2-MSH6 loss in MELF + pattern (7.14% in MELF + population vs 3.96% of MELF- population) CONCLUSIONS: The morphological recognition of MELF pattern is more reliable than immunohistochemical and molecular signatures of EEC in predicting the risk of nodal involvement. The observed higher prevalence of MSH2-MSH6 loss in MELF + group and MLH1-PMS2 loss in MELF- group may suggest a different molecular signature.

Extra-cranial meningioma associated with relapse of immature ovarian teratoma

Ganglioglioma arising in an ovarian teratoma

Prognostic role of perineural invasion in vulvar squamous cell carcinoma: A systematic review and meta-analysis

The prognostic role of perineural invasion (PNI) in vulvar squamous cell carcinoma (VSCC) has not been fully established since few studies on this topic are currently available in the literature. In the present study, we conducted a systematic review and metanalysis of literature data in order to determine if PNI could be an independent prognostic predictor of patient's survival in VSCC. Four electronic databases (PubMed, ISI Web of Science, Scopus and Google Scholar) were searched from their inception to December 2021 for all studies assessing the prognostic value of PNI in VSCC. Multivariate hazard ratios (HRs) for overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS) were pooled. Six studies with 1048 patients were included. PNI was significantly associated with decreased OS (HR = 2.687; p < 0.001), DSS (HR = 2.375; p = 0.014) and PFS (HR = 1.757; p = 0.001), with no statistical heterogeneity among studies and no significant risk of bias across studies. The present meta-analysis highlights that PNI is independently associated with unfavorable prognosis in patients with VSCC. Therefore, PNI should be included in the pathological report of VSCC and considered in combination with other risk factors as a possible criteria for prognostic assessment adjuvant treatment planning inclusion.