Mesonephric-Like Carcinosarcoma of the Ovary Associated with Low-Grade Serous Carcinoma: A Case Report

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.

Mucinous cystadenoma and benign mesonephric-like proliferation in the ovary - Further evidence for clonal relationship

Mesonephric-like adenocarcinomas rarely occur in the uterus and the ovary. Benign mesonephric-like (ML) proliferations and hyperplasia have been described solely within the ovary. Pathogenetic data are very limited. We report a case with microscopic focus of benign ML-proliferation in association with mucinous cystadenoma in the ovary. The immunophenotype was distinct (mucinous tumor: focal weak nuclear positivity for PAX-8, CK 7, patchy cytoplasmic positivity for p16 and negativity for estrogen receptor, CD 10, TTF-1, p53 wildtype; mesonephric component: diffusely positive for PAX-8, CK 7, luminal CD 10, TTF-1, focal staining for estrogen receptor, patchy cytoplasmic for p16, p53 wildtype). On NGS-analysis there was clonal mutation of KRAS p.G12C. The data provide additional evidence for the concept of transdifferentiation (Müllerian tissue representing Wolffian/mesonephric features on histology and immunostaining) within the pathogenesis of mesonephric proliferation of the female genital tract and demonstrate the clonal relationship between these distinct morphologic components.

Ever Expanding Morphologic Patterns of Mesonephric-like Adenocarcinomas of the Uterine Corpus: A Report of Two Tumors and a Brief Review of the Literature

Mesonephric-like adenocarcinoma (MLA) of the endometrium shows a variety of morphologic appearances, including small glands, tubules with eosinophilic materials in the lumen, prominent papillary patterns, spindled cells, solid formations, and corded and hyalinized patterns. Unique morphology, characteristic immunohistochemical staining patterns, molecular alterations, and awareness of the pathologists make it possible to identify this tumor accurately. This report of two additional morphologic patterns, intestinal goblet cells mimicking intestinal-type mucinous carcinoma and squamous differentiation with spindle and epithelioid cells mimicking carcinosarcoma of the endometrium will expand the literature on MLA.

Mesonephric Adenomyofibroma: A Biphasic Vaginal Mass of Mesonephric Type With Molecular Analysis: A Case Report of a Rare Entity

Mesonephric neoplasms of the lower female genital tract are rare. To date, there are scarce reports of benign biphasic vaginal mesonephric lesions, and none have included immunohistochemical and/or molecular analysis. A biphasic neoplasm of mesonephric-type was incidentally identified in the vaginal submucosal tissue of a 55-yr-old woman who underwent a right salpingo-oophorectomy for an ovarian cyst. The well-circumscribed, 5 mm nodule exhibited white-tan, firm homogenous cut surfaces. Microscopic examination showed a lobular arrangement of glands with columnar to the cuboidal epithelium and intraluminal eosinophilic secretions, embedded within a myofibromatous stroma. Cytologic atypia and mitotic activity were absent. Immunohistochemical staining for PAX8 and GATA3 demonstrated diffuse expression in the glandular epithelium, CD10 exhibited a patchy luminal expression pattern, while TTF1, ER, PR, p16, and NKX3.1 were negative. Desmin highlighted a subset of the stromal cells, but myogenin was negative. Whole exome sequencing demonstrated variants of unknown significance in multiple genes including PIK3R1 and NFIA . The morphologic and immunohistochemical profiles are consistent with a benign mesonephric neoplasm. This is the first report describing the immunohistochemical and whole exome sequencing results for a benign biphasic vaginal mesonephric neoplasm. To the best of our knowledge, benign mesonephric adenomyofibroma has not been previously reported in this anatomic location.

Extrauterine Mesonephric-like Carcinoma: A Comprehensive Single Institution Study of 33 Cases

Extrauterine mesonephric-like carcinoma (ExUMLC) shares histologic, immunohistochemical (IHC), and molecular (MOL) features with endometrial mesonephric-like carcinoma (EnMLC). Its rarity and histologic overlap with Mullerian carcinomas contribute to underrecognition of ExUMLC. Aggressive behavior of EnMLC is well-documented; behavior of ExUMLC is yet to be characterized. This study presents the clinicopathologic, IHC, and MOL features of 33 ExUMLC identified over a 20-year time period (2002-2022) and compares the behavior of this cohort to more common upper gynecologic Mullerian carcinomas (low-grade endometrioid, LGEC; clear cell, CCC; high-grade serous, HGSC) and EnMLC diagnosed over the same time period. ExUMLC patients ranged from 37 to 74 years old (median=59 y); 13 presented with advanced stage (FIGO III/IV) disease. Most ExUMLC had the characteristic mixture of architectural patterns and cytologic features, as previously described. Two ExUMLC had sarcomatous differentiation, 1 with heterologous rhabdomyosarcoma. Twenty-one ExUMLC (63%) had associated endometriosis, and 7 (21%) arose in a borderline tumor. In 14 (42%) cases, ExUMLC was part of a mixed carcinoma representing >50% of the tumor in 12. Twenty-six cases (79%) were incorrectly classified as follows: LGEC or HGEC (12); adenocarcinoma, not otherwise specified (3); HGSC (3); LGSC (2); mixed carcinoma (1); carcinosarcoma, Mullerian type (2); seromucinous carcinoma (1); transitional pattern of HGSC (1); and female adnexal tumor of probable Wolffian origin (1). Three patients had occult synchronous endometrial LGEC. IHC facilitated diagnosis in all cases with an expression of GATA-3 and/or TTF-1 in conjunction with decreased hormone receptor expression in most tumors. MOL testing (n=20) identified a variety of mutations, most frequently: KRAS (15); TP53 (4); SPOP (4); and PIK3CA (4). ExUMLC and CCC were more likely to be associated with endometriosis ( P <0.0001). ExUMLC and HGSC had more recurrences compared with CCC and LGEC ( P <0.0001). Histologic subtype was associated with longer disease-free survival for LGEC and CCC versus HGSC and ExUMLC ( P <0.001). ExUMLC trended towards a similar poor overall survival as HGSC compared with LGEC and CCC, and EnMLC trended to shorter survival compared with ExUMLC. Neither finding reached significance. No differences were seen between EnMLC and ExUMLC with respect to presenting stage or recurrence. Staging, histotype, and endometriosis were associated with disease-free survival, but on multivariate analysis, only stage remained as an independent predictor of outcome. The tendency of ExUMLC to present at an advanced stage and have distant recurrence points to more aggressive behavior compared with LGEC with which it is most frequently confused, underscoring the importance of an accurate diagnosis.

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.

The complex and often confusing history, histology and histogenesis of mesonephric, STK11 adnexal tumour and mesonephric-like neoplasms of the upper female genital tract (including broad ligament)

Mesonephric lesions in the female genital tract are uncommon, with those arising from the upper tract being much less frequent than those developing in the lower tract (mesonephric hyperplasia and carcinoma). The most common upper tract lesions include rete cyst/cystadenoma and female adnexal tumour of Wolffian origin (FATWO). The integration of morphological, immunohistochemical and molecular studies on FATWOs has enabled recognition of a novel entity, the STK11 adnexal tumour, which is often associated with Peutz-Jeghers syndrome (~50%) and frequently has a salivary gland morphology but an unknown origin. Similarly, 'mesonephric-like' adenocarcinoma, an entity with striking similarities to mesonephric carcinoma but currently favoured to be of Müllerian derivation based on its association with other Müllerian tumours and molecular findings, has also been recently described, and may histologically mimic both FATWOs and STK11 adnexal tumours. In this review, we provide a historical overview of upper female genital tract mesonephric proliferations and discuss mesonephric lesions, STK11 adnexal tumour, mesonephric-like adenocarcinoma, and mimickers, the most common being endometrioid carcinoma.

Mesonephric-like Adenocarcinoma of the Uterine Corpus: Comprehensive Immunohistochemical Analyses Using Markers for Mesonephric, Endometrioid and Serous Tumors

Mesonephric-like adenocarcinoma (MLA) of the uterine corpus is a rare but distinct malignant tumor of the female genital tract, demonstrating a characteristic morphology and unique immunohistochemical profiles and molecular alterations. We conducted immunohistochemical staining (IHC) to make precise differential diagnoses of uterine MLAs from common histological subtypes of endometrial carcinomas. We collected 25 uterine MLAs and performed IHC for GATA3, TTF1, CD10, ER, PR, p16, p53, and HER2. Seventeen cases (68.0%) showed at least moderate nuclear GATA3 immunoreactivity in ≥25% of tumor cells. Most cases expressed TTF1 (17/21, 81.0%) and CD10 (luminal; 17/21, 81.0%). Heterogeneous TTF1 expression was noted in 12 cases. An inverse pattern of GATA3 and TTF1 staining was observed in eight cases (32.0%). Three cases (12.0%) showed moderate-to-strong ER expression in ≥25% of tumor cells, and two cases (8.0%) showed moderate-to-strong PR expression in ≥5% of tumor cells. These hormone receptor-positive MLAs varied in intensity and proportion of GATA3 staining. None of the 25 cases exhibited either diffuse and strong p16 expression or aberrant p53 expression. Five cases (20.0%) showed equivocal HER2 immunoreactivity (score 2+), but HER2 FISH confirmed that none of them exhibited HER2 gene amplification. In summary, a small subset of uterine MLAs displayed atypical IHC results: focal but strong expression of ER or PR, the complete absence of GATA3 immunoreactivity, the concurrent expression of mesonephric and hormone receptors, and the inverse pattern of GATA3 and TTF1 staining. These unusual immunophenotypes may complicate the differential diagnosis of MLA. Moreover, pathologists should be encouraged to interpret the IHC results cautiously.

Therapeutic Management of Rare Primary Ovarian Neoplasms: Carcinosarcoma, Leiomyosarcoma, Melanoma and Carcinoid

Carcinosarcoma, leiomyosarcoma, melanoma and carcinoid as primary tumors in the ovary are extremely rare. In this paper, the authors reviewed the literature from 2010 to 2021, based on specific criteria, to analyze the treatment of these rare ovarian neoplasms. We also aimed to verify whether modern therapies have been found in recent years. For this article, 80 papers were finally selected. The vast majority of the articles were clinical case reports. Despite single mentions of new potential pharmacological treatments, surgery (radical or fertility-sparing) is definitely the mainstay of treatment. There are currently no treatment guidelines for these tumors. A review of the literature has revealed the use of various adjuvant treatments. We, therefore, believe that a more detailed understanding of the biology of these tumors is necessary in order to find new target points for treatment. We would like to emphasize the importance of creating an international database of rare ovarian tumors which would make it possible to gather data from various oncological centers and enable further research into these neoplasms.