Mesonephric proliferations of the female genital tract

Testosterone-induced Seminal Vesicle-like Differentiation in Cervical Mesonephric Duct Remnants in a Female to Male Transgender Patient

Pure ductal-type mesonephric remnants in the uterine cervix are rare. We report an unusual case in a 31-yr-old of cervical mesonephric remnants of predominantly ductal type exhibiting seminal vesicle-like differentiation in a female-to-male transgender patient receiving long-term testosterone therapy. To the best of our knowledge, this phenomenon has not been previously reported. The impact of testosterone on the female genital tract is likely to be encountered more frequently due to increasing rates of gender-affirming surgery, including long-term androgen use. Awareness of the morphologic features is important as such changes may be misinterpreted as premalignant or malignant lesions. In reporting this unusual case, we briefly review lesions derived from cervical mesonephric remnants and testosterone-associated changes in the female genital tract.

Mesonephric-like adenocarcinoma of the ovary: a case study

Mesonephric-like adenocarcinoma (MLA) is a rare and newly recognized subtype of ovarian and endometrial carcinomas, introduced in the 2020 World Health Organization Classification. This tumor likely originates from Müllerian-derived tissues and often mimics more common ovarian cancers, leading to frequent misdiagnosis. This case study details a 36-year-old woman who presented with urinary symptoms following a hysterectomy. Imaging revealed a significant left ovarian mass, initially misdiagnosed as carcinosarcoma. Pathological evaluation ultimately confirmed MLA, characterized by diverse architectural patterns and specific immunohistochemical markers. The patient underwent chemotherapy due to the locally advanced disease. This case highlights the diagnostic challenges of MLA and emphasizes the need for awareness among clinicians to prevent misdiagnosis. Given its aggressive nature and tendency to early recurrence, further research is essential for establishing standardized diagnostic criteria and treatment protocols for this rare malignancy.

The Clinical Characteristics and Treatment Outcomes of Mesonephric Tumours of the Uterine Cervix: A Systematic Review and Proposal of Embryologically-Oriented Surgical Resection

Background/Objectives: Cervical mesonephric adenocarcinomas (MNACs) are among the rarest neoplasms of the female genital tract. Unlike the majority of cervical cancers, which are predominantly squamous in origin and strongly associated with HPV seropositivity, MNACs are distinct in both histology and pathophysiology. Despite their unique characteristics, MNACs have historically been managed in parallel with squamous cell carcinomas, resulting in a lack of optimised, evidence-based treatment protocols. In this systematic review, we aim to evaluate the current management strategies for MNACs and their associated clinical outcomes. Additionally, we critically appraise existing surgical and adjuvant therapies and propose embryologically oriented surgical techniques to achieve optimal tumour resection. Methods: We performed a systematic search across the MEDLINE, CENTRAL, EMBASE, and ClinicalTrials.gov databases from 1960 to June 2024. The search strategy employed a combination of keywords and MeSH terms, including "Uterine Cervical Neoplasms" [MeSH], "mesonephric tumour", "mesonephric neoplasm", and "mesonephric cancer". All relevant publications, including case reports and case series, were considered. Results: A total of 49 publications were finally included in the analysis, involving a thorough description of 91 MNAC cases. Most patients had stage I disease (70.8%) (n = 51). Hysterectomy was performed in 77 patients. The median follow-up was 29 months (range 1-199 months). Disease recurrence was observed in 35.2% (n = 25) of the cases, with the median disease-free survival (DFS) being 24 months (range 1-199). At the follow-up, 64.8% (n = 46) of patients remained in remission irrespective of the treatment modality, while 27.4% (n = 20) died due to disease progression. Conclusions: Mesonephric neoplasms of the uterine cervix are rare and clinically aggressive cancers that signify poor prognosis. Accurate identification and effective management can be challenging due to their particular anatomic and immunohistochemical characteristics. Therefore, a more tailored embryological-based approach should be considered for an optimal oncologic outcome.

Papillary and ductal patterns of mesonephric-like adenocarcinomas are often overlooked: a retrospective revaluation of over 1000 endometrial carcinomas

AIMS

Mesonephric-like adenocarcinoma (MLA) of the endometrium is often a diagnostic challenge, due to its morphological resemblance to other more common Müllerian neoplasms. This study aimed to retrospectively identify overlooked MLA in a large endometrial carcinoma cohort, using a combination of immunohistochemistry (IHC), morphology and KRAS sequencing.

METHODS AND RESULTS

IHC was conducted on 1094 endometrial carcinomas, identifying 16 potential MLA cases based on GATA3+ and/or TTF1+ and ER- staining patterns, which subsequently underwent detailed histological review, KRAS sequencing and ProMisE molecular classification. Of the IHC screen-positive cases, one was positive for both GATA3 and TTF1, nine were positive for GATA3 only and six were positive for TTF1 only. All IHC screen-positive cases were POLE wild-type. All five tumours in the NSMP category showed morphological features of MLA, while the three MMRd and eight p53abn tumours did not show MLA morphology. The five cases diagnosed as MLA on review were all originally diagnosed as low-grade endometrioid adenocarcinoma probably because of rare morphological patterns, being predominantly papillary or ductal. Four of the five cases harboured a KRAS mutation.

CONCLUSION

This study highlights the importance of a comprehensive diagnostic approach for accurately identifying endometrial MLA and for pathologists to be aware of papillary and ductal patterns in endometrial carcinoma assessment. Further exploration into the molecular landscape of MLA is essential for refining diagnostic criteria and developing targeted therapies.

Cervical Mesonephric Adenocarcinoma Treated with Neoadjuvant Chemotherapy: A Case Report and a Literature Review

INTRODUCTION

Cervical mesonephric ductal adenocarcinoma (MA) is an HPV-independent adenocarcinoma that occurs in middle-aged women. MA originates from remnants of the Wolffian duct that usually regress in females once the induction of sex differentiation is activated. MA is a rare disease that accounts for less than 1% of all cervical adenocarcinomas.

CLINICAL CASE

We report a case of MA in which abdominal radical hysterectomy (ARH) was performed after neoadjuvant chemotherapy (NAC). The patient was a 66-year-old woman with abnormal genital bleeding. A colposcopy examination revealed macroscopic invasive cancer. A pelvic MRI scan revealed a 53 × 26 mm tumor in the cervix, and the histological diagnosis of the cervix was endometrioid carcinoma, with the diagnosis being cervical adenocarcinoma cT1b3N0M0. One course of NAC with paclitaxel-carboplatin (PC) was administered to shrink the tumor and stop the bleeding, and ARH was performed. Postoperative histopathological diagnosis was MA. The surgical margins of the resected specimen were negative, and NAC had been effective, so the patient underwent five courses of PC therapy after surgery. There has been no recurrence 12 months after surgery.

CONCLUSIONS

There is no established standard treatment, but there are reports that PC therapy is effective. It is necessary to search for effective treatments by following up and accumulating further cases.

Mesonephric adenocarcinoma of the uterine cervix with a prominent spindle cell component

Mesonephric adenocarcinomas (MAs) with spindle cell components are rare malignant cervical tumours. In the present study, a retrospective analysis of these tumours was performed. Clinicopathological data were gathered from electronic surgical pathology records, and both immunohistochemistry and targeted next-generation sequencing (NGS) were performed. The present study included three postmenopausal female patients diagnosed with primary uterine cervical MA with prominent spindle cell components, aged 51-60 years. All patients underwent hysterectomy with bilateral salpingo-oophorectomy and pelvic lymph node dissection. There were no recurrences or deaths after surgery. NGS analysis identified KRAS mutations in 2 cases and a PIK3-catalytic subunit α (PIK3CA) mutation in another. Spindle cell components may indicate MAs at an advanced stage. Spindle cell components in MAs are diagnostic pitfalls, and the use of immunohistochemical panels and molecular detection cases with overlapping morphological features is recommended. While KRAS mutations are the most common types of mutations in MAs with spindle cell components, the present study demonstrates that PIK3CA mutations can also occur independently in cases without KRAS mutations.

A rare case report of Herlyn-Werner-Wunderlich syndrome: Unraveling unusual urinary anomalies and literature review

Herlyn-Werner-Wunderlich syndrome (HWWS) is a rare congenital genitourinary abnormality defined by uterine didelphys, obstructed hemivagina, and ipsilateral urological anomalies. Accurate diagnosis and prompt commencement of therapy can be difficult owing to heterogeneous genitourinary malformation among different patients. This is a case report of a patient with rare HWWS with uterine didelphys, obstructed hemivagina, vagina-ureteral remnant fistula (Gartner's duct cyst), and ipsilateral kidney dysgenesis who complained of intermittent abdominal pain during menstruation. The right ureteral remnant of the patient was distinctive, with three portions. The upper section was connected to the right dysplastic kidney, the lower section formed the fistulous tract with the vagina and bladder, while the middle section communicated with Gartner's Duct Cyst, which merged with the vagina and opened to the posterior cavity of hemivagina. The lower section of the right ureter was excised and ligated during laparoscopic surgery, while the upper section was excised. The patient recovered after surgery. We presented this rare case and conducted a literature review to provide a more comprehensive understanding of HWWS. This could help gynecologists effectively reduce misdiagnosis and missed diagnosis, especially when combined with complicated urinary malformation.

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.

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

Mesonephric 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.

Mesonephric-like adenocarcinoma of the ovary

Mesonephric-like adenocarcinoma is a new class of rare subtypes of the female reproductive system. Its clinical symptoms are similar to other types of ovarian tumors. The diagnosis is based on pathological and immunohistochemical methods. The main treatment option is surgery combined with chemotherapy. Few cases have been reported at home and abroad. We reported a case of a 45-year-old woman with a cystic solid mass in the left adnexa. The postoperative pathological diagnosis was mesonephric-like adenocarcinoma of the left ovary and mature cystic teratoma (partial infiltration of the small intestine). This case had no specific clinical symptoms. Immunohistochemical findings showed positive results of GATA3, TTF1, CD10, ER, and PR. Paclitaxel and carboplatin chemotherapy were given after the operation. Currently, no specific criteria are available for diagnosis and treatment of the disease. This article aims to improve the understanding of clinicians in this disease and create a basis for clinical diagnosis and treatment.

Identification of characteristics and construction of nomogram to predict the survival probability of mesonephric carcinoma patients: A population-based analysis and a case report

BACKGROUND

Mesonephric carcinoma (MC) is a very rare tumor with less than 70 cases had been reported. The rarity of MC has restricted its research, resulting in the lack of published guidelines.

OBJECTIVE

To summarize the characteristics and construct an external-validated nomogram to predict the survival of MC patients.

METHOD

Sixty-four qualified patients derived from the Surveillance, Epidemiology, and End Results Plus database, and one patient from the Guangzhou Red Cross Hospital were enrolled. The entire cohort was randomly divided into a development (70%) and a validation cohort (30%). The Kaplan-Meier method and univariate and multivariate Cox regression analyses were applied. Two nomograms were established to predict the 3-to-8-year survival probability of MC patients, which were evaluated by C-index, ROC curves, DCA curves, and calibration plots.

RESULTS

The average survival time of MC patients was 84.22 ± 50.66 months. No significant difference was shown among different groups of race, primary site, tumor differentiated grade, and FIGO stages, while different SEER stages did distinguish patients' survival time, which indicated that the SEER stage standards might be a better staging system in the MC patients than FIGO stage (p = .0835). Additional survival analyses showed that MC patients benefited from shorter waiting times to begin treatment, accepting surgery, regional lymph node examination, radiotherapy, and chemotherapy. Two nomograms were established, both of which got satisfied scores in C-index, ROC curves, DCA curves, and calibration plots.

CONCLUSION

Sufficient regional lymph nodes examined, and applying radiotherapy in high-risk patients are recommended in MC patients. Nomograms established in the present study had good predicting and discriminating capabilities, which would be helpful in patients' individual risk estimation, management, counseling, and follow-up.

Mesonephric-like adenocarcinoma of the ovary with squamoid morular metaplasia, aberrant β-catenin expression, and concurrent FGFR2 and CTNNB1 mutations: a case report

In general, endometrioid-defining features such as squamoid morular metaplasia are not thought to be associated with mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA). Here, we report a case of FGFR2-mutated ovarian MLA with squamoid morular metaplasia accompanied by aberrant nuclear and cytoplasmic β-catenin expression and CTNNB1 mutation. Histologically, the tumor showed classical MLA histology, including well-formed glands with intraluminal eosinophilic secretions and cells with papillary thyroid carcinoma-like nuclei. Squamoid morular metaplasia was intimately associated with the tumor. Glandular epithelial elements, including those immediately associated with the squamoid morules, were negative for ER, but positive for both GATA3 and PAX8; aberrant β-catenin expression was limited to the squamoid morules. This case illustrates the ability of mesonephric neoplasia to exhibit histological features previously thought to be restricted to an endometrioid phenotype.

Mesonephric-like adenocarcinoma of the female genital tract: possible role of KRAS-targeted treatment-detailed molecular analysis of a case series and review of the literature for targetable somatic KRAS-mutations

PURPOSE

Mesonephric-like adenocarcinomas (MLA) of the female genital tract represent a rare and relatively recently described neoplasm exhibiting characteristic morphologic and immunohistochemical findings commonly associated with a KRAS-mutation. Most cases display an aggressive clinical behavior, but knowledge about treatment approaches is limited, especially for targeting KRAS.

METHODS

We report a series of eight cases with a detailed molecular analysis for KRAS. These cases as well as the data of previously published cases with detailed information regarding KRAS-mutational events were reviewed for a potential targeted approach and its prognostic impact.

RESULTS

Both the uterine and ovarian MLA harbor a somatic KRAS-mutation in about 85% of the reported cases, affecting the hotspot codons 12 and 13. 15.7% of the endometrial and 15.6% of ovarian MLA are wild type for KRAS. A p.G12A-alteration was seen in 5.6% (5/89) of the endometrial and in 6.2% (2/32) of the ovarian tumors, for p.G12C in 7.9% and 6.2%, for p.G12D in 32.6% and 34.5% and for p.G12V in 36% and 37.5%, respectively. Very limited data are available regarding the prognostic impact of different mutational sites within the KRAS-gene without significant prognostic impact.

CONCLUSION

Because of a specific p.G12C-KRAS somatic mutation, only the minority of MLA (7.9% with uterine and 6.2% with ovarian primary) are potentially targetable by sotarasib in that rare but aggressive subtype of adenocarcinoma of the female genital tract. Until now, the different location of a somatic KRAS-mutation is of no prognostic impact.

Ipsilateral renal dysgenesis or agenesis with tubulocystic anomalies of the mesonephric duct

Tubulocystic anomalies of the mesonephric duct (MND) are a rare group of related entities with a perplexing clinical presentation. Ultrasound is a useful screening investigation, which can help identify a dysplastic kidney or point to renal agenesis and identify cystic or tubulocystic changes in the structures derived from the ureteric bud or MND. Further evaluation with MRI can help in characterisation and direct management. The presence of a dysplastic kidney or absence of a kidney should prompt further evaluation for associated ureteric abnormalities such as ectopic insertion or ureterocoele, which could lead to a diagnosis of tubulocystic anomaly of the MND.

Contribution

The authors describe two cases, briefly outline the diagnostic approach and summarise the literature on management. Reporting radiologists should be aware of these entities.

Mesonephric-like adenocarcinoma arising from endometrioid adenofibroma in a patient with in-utero exposure to diethylstilbestrol: A case report

Mesonephric-like adenocarcinomas are newly classified rare neoplasms of the upper genital tract. They share identical features with mesonephric adenocarcinomas, with the exception of location. There is ongoing discussion on whether mesonephric-like adenocarcinomas arise from mesonephric remnants or are of Müllerian origin. A 65-year-old woman (G2P1) presented with pelvic pain. Transvaginal ultrasound revealed multiple fibroids, and a robotic total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was planned. Intraoperatively, a complex mass with cystic and solid components was found on the left ovary, which also adhered to the rectosigmoid colon. Pathologic reports documented mesonephric-like adenocarcinoma that appeared to be arising in association with an endometrioid adenofibroma. This case is notable due to the patient's unique background of in-utero exposure to diethylstilbestrol (DES) and multiple gynecological malignancies within her mother, as well as the associated endometrioid adenofibroma. This case contributes evidence to two seemingly opposing theories of mesonephric-like adenocarcinoma histogenesis: the mesonephric remnant theory (supported by the patient's DES exposure), and the Müllerian theory (supported by the associated endometrioid adenofibroma).

Mesonephric-like Adenocarcinoma of the Uterine Corpus: Genomic and Immunohistochemical Profiling with Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution

Data on genetic and immunophenotypical characteristics of uterine mesonephric-like adenocarcinoma (MLA) remain limited. Therefore, we aimed to investigate the clinicopathological, immunohistochemical, and molecular features of uterine MLA. We performed targeted sequencing, array comparative genomic hybridization, and immunostaining in 17, 13, and 17 uterine MLA cases, respectively. Nine patients developed lung metastases. Eleven patients experienced disease recurrences. The most frequently mutated gene was Kirsten rat sarcoma viral oncogene homolog (KRAS; 13/17). Both the primary and matched metastatic tumors harbored identical KRAS (3/4) and phosphatase and tensin homolog deleted on chromosome 10 (1/4) mutations, and did not harbor any additional mutations. A total of 2 of the 17 cases harbored tumor protein 53 (TP53) frameshift insertion and deletion, respectively. Chromosomal gains were detected in 1q (13/13), 10 (13/13), 20 (10/13), 2 (9/13), and 12 (6/13). Programmed cell death-ligand 1 overexpression or mismatch repair deficiency was not observed in any of the cases. Initial serosal extension and lung metastasis independently predicted recurrence-free survival with hazard ratios of 6.30 and 7.31, respectively. Our observations consolidated the clinicopathological and molecular characteristics of uterine MLA. Both clinicians and pathologists should consider these features to make an accurate diagnosis of uterine MLA and to ensure appropriate therapeutic management of this rare entity.

Diagnosis, Treatment and Prognosis of Mesonephric Adenocarcinoma of the Vagina: A Literature Review and a Case Report

BACKGROUND

Mesonephric adenocarcinoma (MA) of the vagina is a rare tumor that arises from mesonephric remnants (Wolffian) in the female genital tract. It is a neoplasm with no significant evidence about its diagnosis, treatment, follow-up and prognosis.

METHODS

Systematic research of the literature was conducted in Scopus, PubMed/MEDLINE, ScienceDirect and the Cochrane Library, including observational prospective and retrospective studies, case series and case reports. We collected data regarding studies related to diagnosis and treatment options evaluating the following aspects: study design, population, treatment type, rate of surgical complications and fertility outcome. We further included a case report of laparoscopic management of MA with pictorial assays.

RESULTS

Thirteen cases of MA of the vagina are available in the literature, including our case report. The median age at diagnosis was 52 years old; the majority of patients reported vaginal bleeding as a symptom (38%); and ultrasound, followed by a magnetic resonance and CT scan were the diagnostic tools most used. In 54% of the cases, a surgical biopsy was performed, and 92% of the patients underwent upfront surgery with an open access or vaginal resection except one case fully managed by minimally invasive surgery. Most of the patients (68%) received adjuvant treatment with chemotherapy or radiotherapy or a combination of them. The mean follow-up period was 6 years.

CONCLUSIONS

Despite the rarity of this cancer and bizarre location, a minimally invasive approach seems feasible after multidisciplinary evaluation. According to the rarity of this tumor, any future case and follow-up data must be reported in the literature in order to enlarge the knowledge about it.

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.

Mesonephric Adenocarcinoma and Mesonephric-like Adenocarcinoma of the Urinary Tract

Given the association of mesonephric adenocarcinoma (MA) of the uterine cervix with florid mesonephric hyperplasia, one would expect MAs to rarely arise in other anatomical locations that harbor mesonephric remnants. In contrast, mesonephric-like adenocarcinoma (MLA) is thought to arise from Müllerian origin without an association with mesonephric remnants. The current case series characterizes 4 cases of MA arising in the urinary bladder (1 woman and 3 men), 1 case of MA in the perirenal region (woman), and 1 case of MLA in the ureter (woman). All cases displayed morphologic features similar to MA of the uterine cervix and MLA of the ovary and endometrium, characterized by predominant tubular and focal glandular/ductal architecture. Mesonephric remnants in the bladder wall were closely associated with adjacent MA in cases 1 and 4. MLA in case 6 was associated with mesonephric-like proliferations and endometriosis. All cases (6/6) were diffusely positive for Pax8, and all displayed a luminal pattern of CD10 staining, except case 4 for which CD10 immunostain was not available for review. Gata3 was either focally positive (cases 1, 2, and 6), negative (case 3), or diffusely positive (case 5). TTF-1 was diffusely expressed in cases 1 and 3 and negative in cases 2, 5, and 6. Although a KRAS G12C somatic mutation was detected in case 6, hotspot mutations in KRAS, NRAS, and PIK3CA were not present in other tested cases. Our study demonstrates that MAs and MLAs of the urinary tract share similar histopathogenesis, morphology, and immunophenotype to their counterparts in the female genital tract. We propose that, in the urinary tract, MA might be classified as a distinctive tumor that arises from mesonephric remnants or presumed Wolffian origin if they are not related to Müllerian-type precursors. The tumor displaying similar morphology and immunoprofile to MA but associated with Müllerian-type precursors should be classified as MLA.

Mesonephric-Like Adenocarcinomas a Rare Tumor: The Importance of Diagnosis

Mesonephric-like adenocarcinomas (MLA) are rare neoplasms that arise in the uterine body and ovary and have been added to the World Health Organisation's recent 2020 classification of female genital cancers. The pathogenesis of MLA is unknown and it remains debated whether they represent mesonephric carcinomas (Wolffian) arising in the endometrium/ovary or endometrioid carcinomas (Müllerian) closely mimicking mesonephric carcinomas. Here we report the case of a 57-year-old woman with an initial misdiagnosis of endometrioid adenocarcinoma on diagnostic biopsy. The patient came to our clinical evaluation for the appearance of menometrorrhagia complicated by anemia for several months. Therefore, she underwent pelvic echo-flowmetry, with indication for diagnostic hysteroscopy with endometrial biopsy, which yielded a positive result for endometrioid endometrial adenocarcinoma. Following staging CT scan and targeted examinations on pulmonary findings, the patient underwent surgery with surprise of definitive diagnosis deponent for endometrial MLA. Our intention is to establish a brief review of the scientific evidence in the literature and the tools available for a correct histological diagnosis, in the light of the scant anatomopathological evidence. Our question gives rise to the motive for the publication: is immunohistochemistry the right way to resolve the diagnostic error at histology, which is usually the only source of diagnostic certainty? This case is intended to alert of diagnostic error that risked having the patient treated as a neoplasm with a favorable prognosis and low degree of aggressiveness instead of for a very aggressive and poor prognosis tumor such as MLA.

Somatic mutation analysis of Mesonephric-Like adenocarcinoma and associated putative precursor Lesions: Insight into pathogenesis and potential molecular treatment targets

•

Mesonephric-like adenocarcinoma is a recently described malignancy of the Müllerian tract.

•

It can behave aggressively.

•

It can arise in association with Müllerian lesions that share its molecular alterations.

•

We analyzed 3 tumors and concurrent Müllerian lesions.

•

We detected a previously unreported potentially actionable H1047Q variant of PIK3CA.

Aims

Mesonephric-like adenocarcinoma (MLA) is a recently described histologic tumor subtype of the Müllerian tract. MLA can arise in association with Müllerian lesions that share common mutations. We report three MLAs and hypothesize that concurrent endometriosis and cystadenofibroma with focal borderline changes might also carry common mutations.

Methods and results

We searched “mesonephric” in our database from 2015 to mid-2021 to retrieve MLA cases. Somatic mutation analysis was performed on tumors and on associated benign proliferative lesions. All MLAs (2 ovarian and 1 uterine) harbored KRAS G12D or G12 V mutations. A PIK3CA alteration (H1047Q) was detected in one MLA and in the associated cystadenofibroma with focal borderline changes. The molecular profile of MLA-associated Müllerian lesions (endometriosis and seromucinous cystadenofibroma with focal borderline changes) was similar to concurrent adenocarcinoma. However, tumor contamination could not be excluded in the endometriotic lesion. Patients presented at various stages, with no evidence of post-operative recurrence after 15 months (FIGO IC) and 33 months (FIGO IIA2). One patient (FIGO IIIA1) died of disease 32 months after surgery.

Conclusions

KRAS mutations commonly characterize MLA. At least some MLA-associated Müllerian lesions show MLA-like genetic profiles, suggesting a precursor role. As far as we are aware, we describe for the first time in MLA the potentially actionable H1047Q variant of PIK3CA.

Mucinous Tumor Coexisting With Mesonephric-like Proliferation/Tumor in the Ovary: A Novel Association

The literature indicates that mesonephric carcinoma (MC) and mesonephric-like adenocarcinoma (MLA) typically lack mucinous and squamous features/differentiation. We report 4 cases of ovarian mucinous tumors (1 mucinous cystadenofibroma and 3 mucinous borderline tumors/atypical proliferative mucinous tumors [MBT/APMT]) co-existing with mesonephric-like lesions which were highlighted by Gata3 and Pax8 expression. All cases contained benign mesonephric-like proliferations (MLP) which focally displayed gastrointestinal-type mucinous metaplasia/differentiation and some were intimately admixed with mucinous glands associated with the mucinous tumor. Metaplastic mucinous epithelium retained expression of Gata3 and Pax8 in some areas while 1 mucinous cystadenofibroma and 1 MBT/APMT were focally positive for Pax8. Along with these mesonephric components, case 1 exhibited features of mesonephric hyperplasia and in 2 cases, 3 and 4, MLA was identified. In case 4, a KRAS c.35G>T (p.Gly12Val) somatic mutation was detected in both the MBT/APMT and the MLA, indicating a clonal origin. This same mutation was also detected in the benign MLP, indicating that it was likely an early genetic event. A CTNNB1 c.98C>T (p.Ser33Phe) somatic mutation, FGFR2 amplification, and CDKN2A/p16 deletion were only detected in the MLA but not in the MBT/APMT. Our result provides evidence to demonstrate the clonal relationship between these morphologically distinct components. Although speculative, we postulate that benign MLPs may give rise to lineage-specific mucinous and mesonephric-like lesions and propose that the MLPs are a new possible origin of some ovarian mucinous tumors. Whether these MLPs arise through transdifferentiation of Müllerian tissue or represent true mesonephric remnants, however, remains largely unknown.

Mesonephric-Like Adenocarcinoma of Uterine Corpus: A Clinicopathological and Targeted Genomic Profiling Study in a Single Institution

Background

Mesonephric-like adenocarcinoma (MLA) is a recently characterized, rare, and aggressive neoplasm that mostly arises in the uterine corpus and ovary. MLA shows characteristic pathological features similar to mesonephric adenocarcinoma of the cervix. The origin of MLA is still controversial and recognition of it remains challenging for pathologists. The aim of this study was to enrich the clinicopathological features of MLA in the uterine corpus and explore its molecular alterations by targeted next-generation sequencing (NGS).

Methods

Four cases of MLA were identified among a total of 398 endometrial carcinomas diagnosed in our institution between January 2014 and December 2021. Immunohistochemistry and targeted NGS spanning 437 cancer-relevant genes were performed.

Results

The most common symptom was abnormal vaginal bleeding, and the average age was 68 years. Histologically, the tumors showed a mixture of varied growth patterns including papillary, glandular, tubular, cribriform, solid, and slit-like architectures, which were lined by columnar to cuboidal cells with overlapping vesicular nuclei and sometimes nuclear grooves. Intraluminal eosinophilic colloid-like secretions were focally evident in three of the four cases. Immunohistochemically, the MLAs were positive for GATA3 (4/4), TTF-1 (3/3), luminal CD10 (3/3), calretinin (2/3), and patchy P16 (3/3) and were negative for ER (0/4) and PR (0/4). The expression of P53 was “wild type” (4/4). By targeted NGS, 3/4 (75%), 2/4 (50%), and 1/4 (25%) cases harbored PIK3CA, KRAS, and PTEN mutations, respectively. None of the tumors had mutations in DNA mismatch repair genes, ARID1A/B, POLE, CTNNB1, SMARCA4, or TP53. At the time of diagnosis, three were presented with FIGO IB stage and one with IIIC stage. Two patients received postoperative chemotherapy and radiotherapy and they were alive without evidence of disease at 8 and 56 months follow-up, respectively. One patient developed pulmonary metastasis 13 months after surgery and chemotherapy, and one was dead of the disease 24 months after the operation without adjuvant therapy.

Conclusions

MLA is a rare and aggressive malignancy, representing approximately 1% of all endometrial carcinomas. It exhibits mixed architectures associated with distinctive immunophenotype and recurrent KRAS and PIK3CA mutations, supporting classified as of Müllerian origin with mesonephric differentiation.

An unusual case of carcinoma with mesonephric-like features with a spindle cell component diagnosed on the Pap test of the uterine cervix: Cytomorphologic and immunophenotypic features and diagnostic pitfalls

Mesonephric-like adenocarcinomas (MLA) are rare neoplasms arising in the cervix, endometrium, and ovary. In contrast to mesonephric carcinomas (MC), mesonephric-like adenocarcinomas are not associated with mesonephric remnants. Both entities have a similar appearance with regards to varying histomorphology patterns, including glandular, tubular, spindled, solid, and papillary, and have a specific immunophenotype and molecular features. We present a case of a 54-year-old HPV-negative woman with a Pap test that exhibits high-grade malignancy. The cell block displayed malignant cells with positive stains for PAX8, GATA3, and TTF1 by immunohistochemistry. The diagnosis of adenocarcinoma with mesonephric like features was rendered. MLA can be challenging on the small specimens and often misinterpreted as other endometrial neoplasms. Furthermore, the accurate diagnosis carries a well-described risk of aggressive clinical behavior.

Mesonephric-like Adenocarcinoma of the Female Genital Tract: From Morphologic Observations to a Well-characterized Carcinoma With Aggressive Clinical Behavior

Mesonephric-like adenocarcinoma (MLA) was introduced as a new tumor type in the endometrium and the ovary in the 2020 World Health Organization (WHO) Classification. This is a rare recently described (2016) and clinically aggressive carcinoma with a propensity for distant spread, especially to the lungs. MLA has a characteristic morphology and immunophenotype (hormone receptor negative; TTF1 and/or GATA3 positive). These neoplasms are commonly associated with KRAS and PIK3CA mutations and in the Cancer Genome Atlas (TCGA) molecular classification of endometrial carcinomas fall into the copy number low/no specific molecular profile category. Although they show significant morphological, immunophenotypic and molecular overlap with cervical mesonephric adenocarcinomas, there are other parameters which suggest a Mullerian origin and, as such, the term MLA seems apt. MLA can be added to the list of endometriosis-associated ovarian neoplasms. In this paper, I outline the series of events which lead to the first description of MLA and review the subsequent literature on this tumor type which has expanded on the morphologic features and immunophenotype, discovered the molecular underpinnings and elucidated the clinical behavior. The discovery of MLA represents an example of "new" entities still to this day being discovered through careful morphologic observations and referral of cases for specialist opinion.

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.

Recurrent primary ovarian leiomyosarcoma preconception, pregnancy, delivery, and puerperal management: A case report and literature review

A primary ovarian leiomyosarcoma (POLMS) is a rare malignant tumor of the ovary. Herein, we report a patient with an early-stage POLMS who underwent unilateral adnexectomy in our department with a subsequent pregnancy, delivery, and tumor recurrence. In this case, the patient was a 29-year-old female with a complaint of abdominal distention who underwent a right adnexectomy for a solid tumor in the right ovary. The pathological diagnosis was a stage IA leiomyosarcoma of the right ovary. One month later, a recurrence in the left ovary tumor was diagnosed. The patient did not agree to further treatment. She subsequently achieved a spontaneous pregnancy and had an uneventful pregnancy and delivery at term. During the puerperium, she underwent radical surgery and chemotherapy with the recommended follow-up evaluation. The literature review shows the pathogenesis of POLMS has not been established. There are no specific tumor markers, and it is difficult to distinguish the nature and origin of the tumor with imaging modalities, thus, early diagnosis is difficult. The malignancy rate is high, and the prognosis of advanced tumors is poor. To properly counsel patients to optimize treatment, more reports of cases, the disease course, treatments, and outcomes are needed.

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.

Primary Cutaneous Enteric Duplication Cyst: A Novel Entity

ABSTRACT

Enteric duplication cysts (EDCs) are rare congenital malformations consisting of double-walled cystic or tubular structures lined by gastrointestinal type epithelium. EDCs share a common muscular wall and blood supply with the adjacent duplicated bowel with very rare exceptions. The majority of EDCs are intraabdominal with cases less commonly intrathoracic or thoracoabdominal. To the best of our knowledge, we present the first reported case of primary cutaneous EDC to occur outside the abdominal and thoracic cavities. A 17-year-old male without a significant medical or surgical history underwent excision of a cystic nodule on the left hip. On histopathology, a dermal to subcuticular cyst exhibited an epithelial lining with 2 distinct components including cuboidal to columnar mucinous cells (CK7+, CK20-, and CDX2-) and complex glandular colonic-type mucosa (CK7-, CK20+, and CDX2+). A thick muscular wall resembling muscularis mucosa and muscularis propria surrounded the cyst. Findings supported a primary cutaneous enteric duplication cyst of uncertain developmental etiology. The novel nature of this entity could represent a diagnostic challenge.

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.

The similarities and differences between mesonephric carcinoma and mesonephric-like carcinoma: Two cases

•

Mesonephric carcinomas are rare cancers that arise from mesonephric remnants.

•

Mesonephric-like carcinomas are similar but with mesonephric differentiation.

•

These cases add to the limited literature of these separate but similar entities.

Management of locally advanced mesonephric carcinoma of the cervix in the setting of Mullerian Duct anomaly spectrum and unilateral renal agenesis: A case report and review of the literature

Cervical mesonephric adenocarcinoma is a rare histologic cervical carcinoma variant arising from remnants of the mesonephric duct. Few clinical cases have been reported in the literature, and given the low rate of occurrence, the optimal management strategy is unknown. Most reported cases involve patients with either early stage (FIGO I) or metastatic disease. Herein, we report the only known case of locally advanced, node-positive cervical mesonephric carcinoma in a 55-year old woman with Mullerian duct anomaly of the uterus, obstructed hemivagina, and ipsilateral renal agenesis. To our knowledge, this would be the first case report with the concurrence of both rare entities. We review the treatment paradigm in this patient, and the literature, including radiotherapy and brachytherapy techniques.

Mesonephric adenocarcinomas in female genital tract: A case series

ABSTRACT

Mesonephric adenocarcinoma (MNAC) is a very rare tumor that originates from mesonephric duct remnants of the female genital tract. Only a few cases were reported in the literature, and most of them occurred in the cervix, extremely rare in the uterine body and ovary. MNAC was rarely reported to arise in the uterine corpus, but never was reported in the ovary. Mesonephric-like adenocarcinomas are recently suggested to describe these neoplasms arising from the uterine corpus and ovary. Due to the rareness of the disease, little is known regarding clinical characteristics, pathological diagnosis, prognosis, and optimal management strategy of MNAC in the female reproductive system. We report a series of MNACs arising from the vagina, cervix, uterine corpus, ovary, and fallopian tube, to summarize the clinical characteristics, pathological diagnosis, treatment, and prognosis.We retrospectively analyzed all MNACs in the female genital tract derived from our institute from January 2010 till January 2020. Patients' clinical details and follow-up were obtained from hospital records and scans were obtained from picture archiving and communication system.A total of 11 patients were included. The median age of onset of symptoms was 52 years. All patients underwent total hysterectomy and bilateral salpingo-oophorectomy, and lymph node dissections were performed in 7/11 (63.6%) patients. Two/eleven (18.2%) received neoadjuvant chemotherapy before surgery and 7/11 (63.6%) received adjuvant chemotherapy after primary surgery. Of the 11 patients, only 1 patient received adjuvant radiation therapy. One patient died at the end point of this study, 9 patients (81.8%) survived and 1 patient was lost to follow-up. The mean follow-up duration was 33.5 months.Although there is no consensus for the optimal treatment of this rare disease, radical surgery is considered to be the initial choice for localized lesion. Given the high malignancy, the majority of MNAC or mesonephric-like adenocarcinoma patients who underwent adjuvant chemotherapy received 4 to 8 cycles of carboplatin/paclitaxel as a first-line treatment after primary surgery with a median progression-free survival of 12 months. Treatment for recurrent disease in these patients included gemcitabine, carboplatin, and paclitaxel. Radiation was very limited in the treatment of the disease.

PAX8-positive, Cytokeratin-positive Intra-abdominal Ewing Sarcoma Masquerading as a Mullerian Carcinoma in a Postmenopausal Female

Extraskeletal Ewing sarcoma presenting as intra-abdominal or pelvic disease in adult female patients is very rare and may lead to diagnostic difficulty due to clinical and histologic overlap with Mullerian adenocarcinomas, which are far more common. We report a case of an intra-abdominal Ewing sarcoma in a postmenopausal female patient whose clinical and radiological presentation closely resembled that of peritoneal carcinomatosis. Biopsy of an omental nodule revealed numerous histologic features suggestive of a Mullerian carcinoma, including gland-like rosettes, strong, diffuse PAX8 immunoreactivity and cytokeratin expression. After excluding other differential diagnostic considerations, the possibility that this might represent an intra-abdominal Ewing sarcoma was entertained. Reverse transcriptase polymerase chain reaction testing demonstrated the presence of an EWSR1-ERG fusion transcript, confirming the diagnosis. The differential diagnostic considerations when dealing with this unusual clinical scenario and the uncommon yet important pitfall of PAX8 immunoreactivity in Ewing sarcoma are discussed.

Mesonephric-like Differentiation of Endometrial Endometrioid Carcinoma: Clinicopathological and Molecular Characteristics Distinct from Those of Uterine Mesonephric-like Adenocarcinoma

When diagnosing endometrial carcinoma cases, we encountered histological features that strikingly resembled uterine mesonephric-like adenocarcinoma (MLA), but the differential diagnosis remained challenging after performing immunostaining. Considering the aggressive biological behavior and poor prognosis of uterine MLA, we believe that the accurate recognition of mesonephric-like differentiation (MLD) is important in the diagnosis of endometrial carcinoma. We aimed to investigate the clinicopathological and molecular characteristics of such cases and compared them with those of uterine MLAs. Five patients diagnosed with endometrioid carcinoma (EC) with MLD were included in this study. Histological evaluation, immunostaining, and targeted sequencing were performed. All five tumors showed typical morphological features of MLA, including densely aggregated tubular structures, deep basophilia under low-power magnification microscopy, eosinophilic intraluminal secretions, and diverse growth patterns. Immunostaining revealed moderate-to-strong nuclear immunoreactivity for estrogen and progesterone receptors in more than 50% tumor cells. The staining intensities and proportions of PAX2 and GATA3 were variable. None of the tumors harbored KRAS mutations. Considering the prognostic implications, ancillary tests, including immunostaining and targeted sequencing, should be performed to accurately differentiate between endometrial EC-MLD and uterine MLA.

Mesonephric and mesonephric-like carcinomas of the female genital tract: molecular characterization including cases with mixed histology and matched metastases

Mesonephric carcinoma of the cervix is a rare tumor derived from Wolffian remnants. Mesonephric-like carcinomas of the ovary and endometrium, while morphologically similar, do not have obvious Wolffian derivation. Here, we sought to characterize the repertoire of genetic alterations in primary mesonephric and mesonephric-like carcinomas, in the distinct histologic components of mixed cases, as well as in matched primary tumors and metastases. DNA from microdissected tumor and normal tissue from mesonephric carcinomas (cervix, n = 8) and mesonephric-like carcinomas (ovarian n = 15, endometrial n = 13) were subjected to sequencing targeting 468 cancer-related genes. The histologically distinct components of four cases with mixed histology and four primary tumors and their matched metastases were microdissected and analyzed separately. Mesonephric-like carcinomas were underpinned by somatic KRAS mutations (25/28, 89%) akin to mesonephric carcinomas (8/8, 100%), but also harbored genetic alterations more frequently reported in Müllerian tumors. Mesonephric-like carcinomas that lacked KRAS mutations harbored NRAS (n = 2, ovary) or BRAF (n = 1, endometrium) hotspot mutations. PIK3CA mutations were identified in both mesonephric-like (8/28, 28%) and mesonephric carcinomas (2/8, 25%). Only mesonephric-like tumors harbored CTNNB1 hotspot (4/28, 14%) and PTEN (3/13, 23%) mutations. Copy number analysis revealed frequent gains of chromosomes 1q and 10 in both mesonephric (87% 1q; 50% chromosome 10) and mesonephric-like tumors (89% 1q; 43% chromosome 10). Chromosome 12 gains were more frequent in ovarian mesonephric-like carcinomas, and losses of chromosome 9 were more frequent in mesonephric than in mesonephric-like carcinomas (both p = 0.01, Fisher's exact test). The histologically distinct components of four mixed cases were molecularly related and shared similar patterns of genetic alterations. The progression from primary to metastatic lesions involved the acquisition of additional mutations, and/or shifts from subclonal to clonal mutations. Our findings suggest that mesonephric-like carcinomas are derived from a Müllerian substrate with differentiation along Wolffian/mesonephric lines.

[Endometrial carcinomas in 2021: What to say and what to do?]

The treatment of endometrial carcinomas relies on histopathological data such as tumor type, grade, stage, and lymphovascular invasion. We herein present the recent advances in the pathological appreciation of these criteria, relying in the last 2020 WHO classification of female genital tumours. Furthermore, molecular typing of endometrial carcinoma has become a rule with strong prognostic and therapeutic implications. The TP53-mutated/serous-like and hypermutated/dMMR groups can be easily identified by the pathologist using immunohistochemistry. The ultramutated/POLE-mutated group identification requires sequencing technologies. We herein explain how easily incorporate this novel histomolecular classification, now included in scholarly society recommendations, in the pathologist routine.

Primary mesonephric adenocarcinoma of the fallopian tube: A case report

BACKGROUND

Mesonephric adenocarcinoma (MNAC) is an extremely rare malignancy in the female genital tract. Only a few cases have been reported in the literature, and most of them occurred in the cervix, with extremely rare cases in the uterine body and ovary. MNAC has never been reported to arise in the fallopian tube.

CASE SUMMARY

A 45-year-old woman was referred to our institution with a history of abdominal pain. Ultrasound revealed a cystic and solid mass in left adnexal region. The patient underwent complete staging surgery when intraoperative pathological examination demonstrated that the mass was malignant. The final histological and immunohistochemical results confirmed the diagnosis of MNAC originating from the fallopian tube. Then she received four cycles of combination chemotherapy with carboplatin plus paclitaxel. The tumor recurred with hepatic metastases 4 mo after initial surgery, and second resection of the tumors in the liver plus partial hepatectomy was performed. She was supplemented with five courses of a new combination chemotherapy with gemcitabine plus carboplatin, and there was no evidence of recurrence within the 22-mo follow-up period after the second surgery.

CONCLUSION

MNAC originating from the fallopian tube is an extremely rare and high malignancy with a poor prognosis. It can be very aggressive, even at early stage. Little is known about the clinical characteristics, pathological diagnosis, prognosis, and optimal management strategy of MNAC originating from the fallopian tube. Herein we report the first case of primary MNAC deriving from the fallopian tube.

Ovarian female adnexal tumor of probable Wolffian origin - Case report

Background

During embryonic development in women, a regression of temporary embryonic structures – mesonephric (Wolffian) ducts occurs. Adnexal tumors of Wolffian duct origin (FATWO) are rare.

Case report

We presented the case of a 64-year-old female patient who was diagnosed with FATWO. After the surgical treatment, the uterus with bilateral adnexal structures was submitted for histopathological analysis. The left ovary was occupied by a tumor measuring 80 × 60 × 50 mm, with smooth, shiny, whitish surface. Tumor cells were medium-sized, relatively uniform, round, and polygonal, with eosinophilic cytoplasm and centrally laid nucleus with fine chromatin, organized into solid, trabecular, and tubular formations. Tumor cells were positive for pancytokeratin (CK), CK7, CD10, neuron-specific enolase (NSE), synaptophysin, calretinin, progesterone, estrogen, and epithelial membrane antigen (EMA).

Conclusion

This case adds a report of a rare tumor to the literature. We must think of it in the differential diagnostic algorithm to make an accurate diagnosis for selecting the best treatment modality.

Atypical Mesonephric Hyperplasia of the Uterus Harbors Pathogenic Mutation of Kirsten Rat Sarcoma 2 Viral Oncogene Homolog (KRAS) and Gain of Chromosome 1q

BACKGROUND/AIM

Mesonephric carcinoma (MNC) is a rare but notable entity of the female genital tract. While many researchers have acknowledged and studied MNC, much remains unknown on the characteristics of mesonephric remnant (MNR) or hyperplasia (MNH). There has not been any study examining the molecular features of MNR and MNH so far. The aim of this study was to investigate the clinicopathological and molecular characteristics of ten uterine mesonephric lesions, including two MNRs without atypia, four MNHs without atypia, and three MNHs with atypia.

MATERIALS AND METHODS

We reviewed the electronic medical records and all available slides of ten cases from multiple institutions. Targeted sequencing and array comparative genomic hybridization were performed.

RESULTS

Three atypical MNHs displayed nuclear enlargement, mild-to-moderate nuclear pleomorphism, and nuclear membrane irregularity, and harbored pathogenic Kirsten rat sarcoma 2 viral oncogene homolograt sarcoma 2 viral oncogene homolog (KRAS) mutation. Two of those that co-existed with MNC harbored the same sequence alterations as each of their adjacent MNC. One of the three atypical MNHs harbored chromosome 1q gain.

CONCLUSION

Atypical MNH is a potential premalignant lesion in which KRAS mutation and chromosome 1q gain play an important role in the early stage of mesonephric carcinogenesis.

Cervical stromal involvement by endometrial 'hyperplasia': a previously unreported phenomenon with recommendations to report as stage II endometrial carcinoma

A subtle 'burrowing' pattern of cervical stromal involvement by low-grade endometrioid adenocarcinoma of the uterine corpus is described in the literature. We report a small case series in which this pattern of cervical stromal involvement, warranting a diagnosis of endometrioid adenocarcinoma in the cervix, occurred in association with sometimes subtle endometrioid proliferations within the endometrium which fall short of the criteria for endometrioid adenocarcinoma and are in keeping with atypical hyperplasia or hyperplasia without atypia. In reporting this phenomenon, which has not been described previously, we highlight the importance of immunohistochemistry in the differential diagnosis, particularly in the exclusion of primary cervical glandular lesions, including those of mesonephric type. We discuss the differential with primary endometrioid adenocarcinoma (including minimal deviation type) of the cervix and other lesions and stress the importance of sampling the endometrium and lower uterine segment in their entirety in order to exclude an atypical hyperplasia or an adenocarcinoma in these locations. Although the pathogenesis of the cervical lesion we report is controversial, we believe that it is most likely a result of spread from the endometrium and results in the unusual occurrence of the malignant nature of the lesion being only apparent in the secondary rather than the primary lesion. We provide recommendations for reporting such cases and recommend designating them as stage II endometrial carcinoma, although the prognostic and management implications of such cases will only be clear once further cases with follow-up are reported.

Female Adnexal Tumor of Probable Wolffian Origin: Clinicopathologic and Immunohistochemical Study of 11 Cases

CONTEXT.—

Female adnexal tumor of probable Wolffian origin (FATWO) often is a diagnostic challenge given its rarity, histologic heterogeneity, and lack of specific immunoprofile.

OBJECTIVE.—

To further understand the clinicopathologic and immunohistochemical features of this rare entity.

DESIGN.—

We studied the clinical, morphologic, and immunohistochemical features of a cohort of 11 FATWO cases from our institute.

RESULTS.—

Patients' age ranged from 25 to 76 years (mean, 55 years). Tumor size ranged from 0.5 to 18 cm (mean, 2.7 cm). Histopathologically, most tumors presented with low-grade cytologic features with low mitotic activity and lack of necrosis. Three main growth patterns were appreciated: solid, tubular, and sievelike patterns. Higher-grade nuclear atypia, increased mitotic activity, and focal necrosis were seen in 2 cases. These 2 cases were clinically considered malignant FATWO mainly because of their extra-adnexal involvement. Immunohistochemical studies found that tumor cells were positive for CD10 (11 of 11, 100%), AE1/3 (8 of 8, 100%), CAM 5.2 (4 of 5, 80%), and cytokeratin 7 (CK7; 7 of 10, 70%); and focally positive for calretinin (4 of 10, 40%), inhibin (4 of 10, 40%), epithelial membrane antigen (EMA; 3 of 9, 33%), and steroidogenic factor-1 (SF-1; 2 of 8, 25%). Lack of immunoreactivity to PAX8 and GATA3 in almost all cases indicates that FATWO is different from the tumors derived from the Müllerian or mesonephric origins. All patients with available follow-up had favorable prognosis.

CONCLUSION.—

The broad spectrum of clinical presentation, various morphologic features, and overlapping immunophenotype suggest that FATWO is a diagnosis of exclusion until it is further defined at the molecular and immunohistochemical levels.

Mesonephric (Wolffian-derived) Adenocarcinoma of the Female Urethra

The current World Health Organization (WHO) classification of adenocarcinoma of the urinary tract including the urethra includes uncommon Müllerian-derived carcinomas such as clear cell and endometrioid adenocarcinomas. The concept of primary mesonephric (Wolffian-derived) adenocarcinoma (MA) in the urethra (and urinary tract in general) is currently regarded as controversial as the term "mesonephric" had been also inaccurately applied in the past to label Müllerian-derived carcinomas, particularly clear cell adenocarcinoma. Further, pathologically well-documented or bona fide urethral MAs have not yet to be reported. Herein, we describe 2 examples of MA in elderly females that primarily presented in the urethra and manifested clinically with obstructive lower urinary tract symptoms. Both tumors exhibited histology similar to those in MAs of the female genital tract including the distinctive tubular proliferations with luminal eosinophilic materials. The first case, in addition, showed a variety of patterns including ductal (glandular), solid, fused/sieve-like tubules, dilated tubules, and spindled cells. The second case also showed a transition to the more irregular and poorly formed tubular proliferation of cells with greater nuclear atypia and with a desmoplastic response. Both tumors showed positivity for PAX8, GATA3, and luminal CD10, and 1 tumor analyzed harbored KRAS and ARID1A mutations. One patient received neoadjuvant chemotherapy and underwent resection but had local tumor recurrence and metastasis to the lungs and lumbar spine 12 months after presentation. In conclusion, MA, similar to those occurring in the female genital tract and distinct from the recognized Müllerian-derived carcinomas, may present primarily as urethral tumors. MA in the urethra probably shares a common pathogenesis with vaginal MA as both may originate from the same caudal loci of mesonephric remnants along the closely apposed anterior vaginal and posterior urethral walls. MA should be considered in future classifications for urethral tumors and we recommend that the confusing term "mesonephroid adenocarcinoma" should no longer be used.

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

Mesonephric adenocarcinomas are rare tumors of the female genital tract, thought to arise from embryonic mesonephric remnants, primarily in the cervix and vagina. Conversely, endometrial and ovarian mesonephric adenocarcinomas may have a different pathogenesis, probably originating from transdifferentiated Müllerian carcinomas, as demonstrated by the association of these neoplasms with endometriosis and ovarian serous tumors. For this reason, in the endometrium and in the ovary, they are defined as "mesonephric-like adenocarcinomas". Some cases of mesonephric carcinomas of the female genital tract have been reported to show a sarcomatous component and have been defined as "mesonephric carcinosarcomas", characterized by poor prognosis and high metastatic behavior, but this entity has never been described in the ovary. The case herein presented is of a 74-year-old female with abdominal discomfort and a complex ovarian mass. Histological and immunohistochemical analysis showed features of ovarian mesonephric-like carcinoma combined with a low-grade serous component, in support of the theory of a Müllerian origin of these neoplasms. The tumor also revealed foci of chondrosarcomatous differentiation, never before reported in the ovary, showing a similar immunohistochemical profile to the mesonephric-like elements. This work thus describes the first reported case of ovarian mesonephric-like carcinosarcoma.

Cervical malignant mixed mesonephric tumour: A case report with local recurrence after six-years and next-generation sequencing analysis with particular reference to the ataxia telangiectasia mutated gene

Malignant mixed mesonephric tumours (MMMsT) of the female genital tract are extremely rare, and the majority are located in the wall of the cervix uteri. At present, there are no reports of the molecular characterisation of MMMsT of the female genital tract. Herein, we report the morphological, immunohistochemical and molecular features of this rare malignancy using next-generation sequencing (NGS) analysis. A 58-year-old woman presented with vaginal bleeding. In 2013, she had been diagnosed with a cervical carcinosarcoma of probable mesonephric origin and International Federation of Gynaecology and Obstetrics (FIGO) stage IB that had been treated by total hysterosalpingo-oopherectomy without adjuvant chemo-radiotherapy. Ultrasonography showed a vaginal mass measuring 25 mm in the maximum dimension. Biopsy was performed and showed a biphasic neoplasm composed of adenocarcinoma and sarcoma. Immunohistochemistry showed positive staining for epithelial membrane antigen (EMA), pancytokeratin (MNF116), paired box 8 (PAX-8), β-catenin, cytokeratin 7, cyclin D1, GATA3 and CD10. Androgen receptor positivity was detected in very limited areas. Cytokeratin 20, carcinoembryonic antigen (CEA), oestrogen receptor (ER), progesterone receptor (PR), transcription termination factor 1 (TTF1), Wilm's tumour antigen-1 (WT-1), calretinin and p16 were negative. The immunohistochemical profile was consistent with mesonephric origin. NGS analysis identified a variant of the ataxia-telangiectasia mutated (ATM) gene (p.Phe858Leu; c.2572 T>C; COSM21826). The number of detected allele frequency reads of ATM mutation following clinical relapse was higher, compared to its baseline: 65 vs. 96%. The differential diagnosis of MMMsT includes mesonephric hyperplasia, malignant mixed Mullerian tumour (carcinosarcoma), endometrioid adenocarcinoma and endometrial stromal sarcoma. The clinical significance of the observed ATM variant in the case reported herein is unknown. The present findings need further verification, as the mutation in ATM may result in chemotherapy resistance or conversely, may be exploited for targeted therapies.

Cervical Mesonephric Adenocarcinoma: A Case Report of a Rare Gynecological Tumor from Embryological Remains of the Female Genital Tract

INTRODUCTION

 Malignant mesonephric tumors are uncommon in the female genital tract, and they are usually located where embryonic remnants of Wolffian ducts are detected, such as the uterine cervix. The information about these tumors, their treatment protocol, and prognosis are scarce.

CASE REPORT

 A 60-year-old woman with postmenopausal vaginal bleeding was initially diagnosed with endometrial carcinoma. After suspicion co-testing, the patient underwent a loop electrosurgical excision of the cervix and was eventually diagnosed with mesonephric adenocarcinoma. She was subjected to a radical hysterectomy, which revealed International Federation of Gynecology and Obstetrics (FIGO) IB1 stage, and adjuvant radiotherapy. The follow-up showed no evidence of recurrence after 60 months.

CONCLUSION

 We present the case of a woman with cervical mesonephric adenocarcinoma. When compared with the literature, this case had the longest clinical follow-up without evidence of recurrence, which reinforces the concept that these tumors are associated with a favorable prognosis if managed according to the guidelines defined for the treatment of patients with cervical adenocarcinomas. Though a rare entity, it should be kept in mind as a differential diagnosis for other cervical cancers.