Microscopic extraovarian sex cord proliferations: an undescribed phenomenon.

AIMS: To report a previously undescribed phenomenon of incidentally detected microscopic proliferations of sex cord cells, often mimicking adult granulosa cell tumour or sex cord tumour with annular tubules, in extraovarian locations. METHODS AND RESULTS: The six cases were in patients aged 23-58 years. The proliferations were located in the fallopian tube in three cases, and in paraovarian connective tissues, the pelvic side wall, and appendiceal serosa (one case each). Microscopically, they were typically composed of well-demarcated nests of regular cells with round/ovoid vesicular nuclei, some containing grooves. Microfollicular and/or cribriform arrangements were present in three cases. In five cases, the sex cord lineage was confirmed by positive staining with inhibin and/or calretinin and other sex cord markers. FOXL2 mutation analysis was performed in one case, but was inconclusive. Bilateral oophorectomies and bilateral cystectomies were performed in three cases and one case respectively; there was no sex cord-stromal neoplasm in the removed ovaries. In the two cases in which the ovaries were not removed, imaging showed no suspicious features. Follow-up in four cases (11 months-6 years) has been uneventful. CONCLUSIONS: The pathogenesis of these microscopic extraovarian sex cord proliferations is unknown, but they may represent non-neoplastic proliferations of embryonic remnants.

Diagnosis of Ovarian Carcinoma Histotype Based on Limited Sampling: A Prospective Study Comparing Cytology, Frozen Section, and Core Biopsies to Full Pathologic Examination.

Growing insights into the biological features and molecular underpinnings of ovarian cancer has prompted a shift toward histotype-specific treatments and clinical trials. As a result, the preoperative diagnosis of ovarian carcinomas based on small tissue sampling is rapidly gaining importance. The data on the accuracy of ovarian carcinoma histotype-specific diagnosis based on small tissue samples, however, remains very limited in the literature. Herein, we describe a prospective series of 30 ovarian tumors diagnosed using cytology, frozen section, core needle biopsy, and immunohistochemistry (p53, p16, WT1, HNF-1ß, ARID1A, TFF3, vimentin, and PR). The accuracy of histotype diagnosis using each of these modalities was 52%, 81%, 85%, and 84% respectively, using the final pathology report as the reference standard. The accuracy of histotype diagnosis using the Calculator for Ovarian Subtype Prediction (COSP), which evaluates immunohistochemical stains independent of histopathologic features, was 85%. Diagnostic accuracy varied across histotype and was lowest for endometrioid carcinoma across all diagnostic modalities (54%). High-grade serous carcinomas were the most overdiagnosed on core needle biopsy (accounting for 45% of misdiagnoses) and clear cell carcinomas the most overdiagnosed on frozen section (accounting for 36% of misdiagnoses). On core needle biopsy, 2/30 (7%) cases had a higher grade lesion missed due to sampling limitations. In this study, we identify several challenges in the diagnosis of ovarian tumors based on limited tissue sampling. Recognition of these scenarios can help improve diagnostic accuracy as we move forward with histotype-specific therapeutic strategies.

SMARCA4-deficient Uterine Sarcoma and Undifferentiated Endometrial Carcinoma Are Distinct Clinicopathologic Entities.

Undifferentiated and dedifferentiated endometrial carcinomas (UDEC) are aggressive uterine tumors which may show loss of expression of SMARCA4 (BRG1) or SMARCB1 (INI-1). The recently described SMARCA4-deficient undifferentiated uterine sarcoma (SDUS) has a morphology which overlaps with UDEC. In this study, we compared clinical, morphologic, immunohistochemical, and molecular characteristics to identify features which differentiate SDUS from UDEC. Cases of SDUS (n=12) were compared with cases of UDEC (n=84, 55 of which were previously published). Immunohistochemistry was performed for p53, mismatch repair proteins, claudin-4, SMARCA4, and SMARCB1. Targeted molecular profiling was performed on 15 cases. Patients with SDUS were significantly younger than those with UDEC (mean 35.8 vs. 61.2 y, P=0.0001). UDEC and SDUS showed morphologic overlap; however, phyllodiform architecture favored a diagnosis of SDUS (36% vs. 0%, P=0.005), while prominent nuclear pleomorphism was only seen in some cases of UDEC (0% vs. 24%, P=0.15). Compared with SDUS, UDEC more frequently showed TP53 mutations (0% vs. 34%, P=0.03), microsatellite instability (0% vs. 44%, P=0.006), and intact SMARCA4 and SMARCB1 (0% vs. 80%); a panel combining these immunohistochemical markers had a sensitivity of 100% and specificity of 92% in distinguishing SDUS and UDEC. Cases of UDEC had mutations in genes associated with endometrial adenocarcinomas (eg, TP53, PTEN, PIK3CA) and occasionally SMARCA4, while SDUS was characterized solely by inactivating mutations in SMARCA4. Disease-specific survival was shorter in SDUS than UDEC (median survival 9 and 36 mo, P=0.01). In conclusion, SDUS occurs in younger patients than UDEC, has a worse prognosis, and in most cases has a distinct molecular and immunohistochemical profile.

Evaluation of pathology review at gynaecological oncology multidisciplinary team meetings: a 5-year prospective analysis of cases with major diagnostic discordance.

Multidisciplinary team meetings (MDTs) play an essential role in the management of patients with newly diagnosed and recurrent cancers, and often include review of pathology specimens that were initially assessed in external departments. Many studies have demonstrated a low but significant rate of diagnostic disagreement following such review but the pathological findings have seldom been detailed. We present a prospective 5-year study of all external cases reviewed at the Western Australian Gynaecological Oncology MDT focusing upon those cases with major diagnostic discordance likely to impact patient management. In total, 1275 cases were reviewed of which 132 (10.4%) were considered discordant including 48 (3.8%) with major discordance. Different interpretation of the presence and/or extent of tumour invasion accounted for a significant proportion of cases and in particular some adenocarcinoma and squamous carcinoma variants were initially reported to show only in situ or minimally invasive disease. Endometrial high-grade serous carcinoma was under-recognised and on occasion reassignment of tumour origin including metastasis to the gynaecological tract was facilitated by additional clinical information and supported by appropriate immunohistochemistry. This study supports the role of pathology review at MDTs and highlights problematic lesions that may merit a low threshold for additional opinion and ancillary studies.

The histomorphology of Lynch syndrome-associated ovarian carcinomas: toward a subtype-specific screening strategy.

Women with Lynch syndrome (LS) are at increased risk for the development of epithelial ovarian cancer (OC). Analogous to previous studies on BRCA1/2 mutation carriers, there is evidence to suggest a histotype-specific association in LS-associated OCs (LS-OC). Whereas the diagnosis of high-grade serous carcinoma is an indication for BRCA1/2 germline testing, in contrast, there are no screening guidelines in place for triaging OC patients for LS testing based on histotype. We performed a centralized pathology review of tumor subtype on 20 germline mutation-confirmed LS-OCs, on the basis of morphologic assessment of hematoxylin and eosin-stained slides, with confirmation by immunohistochemistry when necessary. Results from mismatch-repair immunohistochemistry (MMR-IHC) and microsatellite instability (MSI) phenotype status were documented, and detailed pedigrees were analyzed to determine whether previously proposed clinical criteria would have selected these patients for genetic testing. Review of pathology revealed all LS-OCs to be either pure endometrioid carcinoma (14 cases), mixed carcinoma with an endometrioid component (4 cases), or clear cell carcinoma (2 cases). No high-grade or low-grade serous carcinomas or mucinous carcinomas of intestinal type were identified. Tumor-infiltrating lymphocytes were prominent (≥40 per 10 high-powered fields) in 2 cases only. With the exception of 1 case, all tumors tested for MMR-IHC or MSI had an MMR-deficient phenotype. Within this cohort, 50%, 55%, 65%, and 85% of patients would have been selected for genetic workup by Amsterdam II, revised Bethesda Guidelines, SGO 10% to 25%, and SGO 5% to 10% criteria, respectively, with <60% of index or sentinel cases detected by any of these schemas. To further support a subtype-driven screening strategy, MMR-IHC reflex testing was performed on all consecutive non-serous OCs diagnosed at 1 academic hospital over a 2-year period; MMR deficiency was identified in 10/48 (21%) cases, all with endometrioid or clear cell histology. We conclude that there is a strong association between endometrioid and clear cell ovarian carcinomas and hereditary predisposition due to MMR gene mutation. These findings have implications for the role of tumor subtype in screening patients with OC for further genetic testing and support reflex MMR-IHC and/or MSI testing for newly diagnosed cases of endometrioid or clear cell ovarian carcinoma.