Ovarian Brenner tumors and Walthard nests: a histologic and immunohistochemical study

Walthard Cell Nests Leading to 18 F-FDG Increased Uptake of Fallopian Tube

ABSTRACT

We present 18 F-FDG PET/CT findings of fallopian tube with Walthard cell nests. The images revealed a thickening of the bilateral fallopian tubes with increased FDG uptake. Malignant tumor or tuberculosis of the fallopian tube was suspected. Histopathology suggested fallopian tube with Walthard cell nests.

Malignant Brenner Tumor of the Ovary: A Critical Reappraisal

Malignant Brenner tumors (MBTs) are rare epithelial tumors of the ovary, most likely arising from benign and borderline Brenner tumors. MBTs may be misdiagnosed as other primary carcinomas or nonepithelial tumors of the ovary as well as metastatic carcinomas. Accurate diagnosis usually requires clinical-radiologic correlation, extensive sampling, and immunohistochemical studies. Treatment is not standardized and may include surgery with or without chemotherapy. More than half of MBTs are diagnosed at stage I, with 47.7% and at least 20% recurrence and mortality rates, respectively. Awareness of key diagnostic features and pitfalls is essential to differentiate MBT from its mimics and ensure optimal clinical management. This comprehensive review includes classification, etiopathogenesis, historical overview, epidemiology, clinical features, treatment, prognosis, gross pathology, key morphologic features, ancillary testing, and differential diagnostic considerations for ovarian MBTs.

FOXA1 expression and its association with mucin expression and KRAS mutation in ovarian mucinous tumors: implications for tumor progression and differentiation

This study aimed to investigate forkhead box A1 (FOXA1) expression in ovarian mucinous tumors and its association with mucin expression and KRAS mutation status to clarify its role in tumor progression and differentiation. We analyzed 57 normal tissues or benign ovarian lesions, 110 mucinous ovarian tumors, including mucinous carcinomas, and 214 other ovarian epithelial carcinomas using immunohistochemistry for FOXA1, MUC2, MUC5AC, and MUC6. We also performed KRAS mutation analysis. Strong nuclear staining of FOXA1 was observed in Walthard nests, Brenner tumors, and fallopian tube ciliated epithelium. FOXA1 expression was significantly associated with mucinous histology in ovarian epithelial carcinomas (P < 0.001). In mucinous tumors, FOXA1 was expressed in 73.6% of cystadenomas, 91.4% of borderline tumors, 100% of borderline tumors with intraepithelial carcinomas, and 87.5% of carcinomas. MUC2 expression progressively increased from mucinous cystadenomas to borderline tumors (P < 0.050) and significantly correlated with FOXA1 expression (P = 0.024). The prevalence of KRAS mutations also tended to increase with the malignancy of mucinous tumors (P < 0.050); however, KRAS mutations were significantly enriched in FOXA1-negative cystadenomas compared with FOXA1-positive cystadenomas (P < 0.050). A stepwise increase was noted in the percentage of both KRAS mutations and FOXA1 expression from cystadenoma to carcinoma. Mucinous ovarian tumors commonly express FOXA1. The co-occurrence of KRAS mutations and FOXA1 expression may be important for driving the progression and intestinal differentiation of mucinous ovarian tumors.

Immunohistochemistry Markers in Ovarian and Fallopian Tube Neoplasms: a Comprehensive Review

Immunohistochemistry (IHC) has emerged as a crucial tool in diagnosing and managing ovarian cancer, offering invaluable insights into tumor biology and guiding therapeutic decisions. The intricate histopathological landscape of ovarian cancer presents challenges in accurate diagnosis and classification. IHC offers a complementary approach, aiding in the characterization of tumor subtypes, prognostication, and prediction of treatment response. By targeting specific biomarkers, IHC enables the identification of diverse histological features and molecular alterations associated with ovarian malignancies. The integration of IHC into routine diagnostic workflows enhances diagnostic accuracy, aids in the subclassification of ovarian tumors, and facilitates personalized treatment strategies. Emphasis is placed on the judicious selection of antibody panels tailored to specific clinical scenarios, ensuring optimal utilization of resources and minimizing diagnostic pitfalls. Overall, this review underscores the pivotal role of IHC in refining the diagnosis, prognostication, and management of ovarian cancer, highlighting its significance in the era of precision medicine. By leveraging the molecular insights provided by IHC, clinicians and pathologists can optimize patient care and improve outcomes in ovarian cancer management.

The uterine secretome initiates growth of gynecologic tissues in ectopic locations

Endosalpingiosis (ES) and endometriosis (EM) refer to the growth of tubal and endometrial epithelium respectively, outside of their site of origin. We hypothesize that uterine secretome factors drive ectopic growth. To test this, we developed a mouse model of ES and EM using tdTomato (tdT) transgenic fluorescent mice as donors. To block implantation factors, progesterone knockout (PKO) tdT mice were created. Fluorescent lesions were present after oviduct implantation with and without WT endometrium. Implantation was increased (p<0.05) when tdt oviductal tissue was implanted with endometrium compared to oviductal tissue alone. Implantation was reduced (p<0.0005) in animals implanted with minced tdT oviductal tissue with PKO tdT endometrium compared to WT endometrium. Finally, oviductal tissues was incubated with and without a known implantation factor, leukemia inhibitory factor (LIF) prior to and during implantation. LIF promoted lesion implantation. In conclusion, endometrial derived implantation factors, such as LIF, are necessary to initiate ectopic tissue growth. We have developed an animal model of ectopic growth of gynecologic tissues in a WT mouse which will potentially allow for development of new prevention and treatment modalities.

An Incidental Finding of Low-Grade Appendiceal Mucinous Neoplasm in a Case of Borderline Brenner Tumor of the Ovary

The concurrent presentation of a low-grade appendiceal mucinous neoplasm (LAMN) and a borderline Brenner tumor (BT) of the ovary are exceedingly rare. Brenner tumors stand out as a particularly uncommon form, making up only around 5% of all benign epithelial tumors of the ovary. Among the ovarian Brenner, the borderline subtype is even rarer. Appendiceal neoplasm (LAMN) and right ovarian BT cannot be distinguished due to their anatomical position. LAMN is often an incidental finding and at later stages when left undiagnosed may lead to pseudomyxoma peritonei (PMP). This case describes a postmenopausal woman in her 50s experiencing abdominal pain and bloating for a week. Elevated carcinoembryonic antigen (CEA) levels and imaging suggested a potential right ovarian tumor. Interestingly, it revealed a unique combination of borderline Brenner tumor of the right ovary and low-grade appendiceal mucinous neoplasm.

Diagnostic roles of PAX8 immunohistochemistry in ovarian tumors

OBJECTIVE

This study aimed to elucidate the diagnostic roles of PAX8 immunohistochemistry in various ovarian tumors.

METHODS

We searched through the PubMed database and selected the eligible studies to perform the meta-analysis. The PAX8 immunohistochemical expression rates of various ovarian tumors, including primary and metastatic carcinomas, were analyzed. In addition, the subgroup analysis based on tumor behaviors was performed.

RESULTS

The PAX8 expression rates were 0.056 (95% confidence interval [CI] 0.008-0.307), 0.400 (95% CI 0.228-0.600), 0.741 (95% CI 0.578-0.857), and 0.738 (95% CI 0.666-0.799) in normal ovary and benign, borderline, and malignant ovarian tumors, respectively. The PAX8 expression rates of serous and transitional cell carcinomas were 0.937 (95% CI 0.882-0.967) and 0.918 (95% CI 0.841-0.959). In addition, the PAX8 expression rate of mucinous carcinomas was 0.393 (95% CI 0.285-0.512). However, metastatic carcinomas showed a significantly lower PAX8 expression rate than primary ovarian cancers (P < 0.001 in the meta-regression test). In cytologic specimens, PAX8 expression rates of serous and endometrioid carcinomas were 0.905 (95% CI 0.832-0.948) and 0.714 (95% CI 0.327-0.928), respectively.

CONCLUSION

PAX8 expression rate was significantly higher in serous ovarian tumors than in mucinous ovarian tumors. In addition, PAX8 expression rates were significantly higher in primary ovarian cancers than in metastatic carcinomas.

Cystic Walthard Nests of the Peritoneal Diaphragm: A Report of 3 Cases of a Common Process at an Unusual Site and Occurring in Patients With Endometriosis

Nests of cells resembling urothelium, eponymously named "Walthard nests," are well-known incidental findings over the fallopian tube and occasionally undergo cystification resulting in clinical detection and surgical removal. Only rarely is this process noted outside the pelvic peritoneum. Herein we describe cystic Walthard nests occurring in the diaphragmatic peritoneum of three patients (aged 25, 36, and 39 yr) undergoing surgical evaluation for presumed endometriosis. In each case, small pearly white nodules on the diaphragmatic peritoneum were noted and biopsied. Microscopic examination revealed cystic spaces filled with pale eosinophilic secretion. The cysts were lined mostly by stratified transitional cells with pale eosinophilic to focally clear cytoplasm. Umbrella cells were focally present in all cases, and 1 showed focal glandular differentiation resembling cystitis glandularis. In areas, the epithelial cells became flattened and attenuated and nuclei were bland. By immunohistochemistry, all were positive for GATA3, cytokeratin 7, and BEREP4 and negative for cytokeratin 20, estrogen receptor, and WT-1. Walthard nests can rarely occur outside the pelvic peritoneum where they may be noted incidentally during surgery for other indications. This should be readily distinguished pathologically from other peritoneal lesions but lack of significant prior comment of them occurring on the diaphragm may result in diagnostic difficulty.

Mucinous Borderline Tumor Associated with Mesonephric-like Proliferation: Further Evidence for a Possible New Origin of Ovarian Mucinous Neoplasms

Some ovarian mucinous tumors are thought to originate from Brenner tumors and teratomas; however, data are limited on what could be the origin for the remaining tumors. We report a new case of ovarian mucinous borderline tumor/atypical proliferative mucinous tumor (MBT/APMT) co-existing with a mesonephric-like proliferation (MLP)/mesonephric-like hyperplasia (MLH). The patient was a 58-year-old woman who presented with a pelvic mass and abdominal pain. Pathology demonstrated an 11 cm MBT/APMT in the left ovary. In addition, the tumor contained one focal area (<1% of total tumor volume) of MLP/hyperplasia adjacent to, or intimately admixed with, mucinous epithelium, with an immunophenotype of diffuse Pax8 and Gata3 expression and negative TTF-1, ER, and PR staining. Pax8 was also weakly positive in the MBT/APMT component. Some mesonephric-like glands partially exhibited gastrointestinal-type mucinous metaplasia/differentiation. A polymerase chain reaction (PCR)-based Sanger sequencing demonstrated that a KRAS G12V mutation was present in both MLP/MLH and MBT/APMT components, providing further evidence to support their clonal relationship. We previously reported a series of similar cases and demonstrated a novel association between MLP, mesonephric-like adenocarcinoma and ovarian mucinous tumor. It is conceivable that benign MLPs may have ability to differentiate to lineage-specific mucinous lesions, and, as such, they may serve as a possible new origin of some ovarian mucinous neoplasms; in particular, Pax8-positive tumors. The current case provides additional evidence to support this theory.

Cytologic features of sex cord-stromal tumors in women

BACKGROUND

Gynecologic sex cord-stromal tumors (SCSTs) arise from sex cords of the embryonic gonad and may display malignant behavior. We describe the cytomorphologic features of SCSTs in females, including adult and juvenile granulosa cell tumors (AGCTs and JGCTs), Sertoli-Leydig cell tumors (SLCTs), and steroid cell tumors (SCTs).

METHODS

We retrieved available cytology slides from females with a histologic diagnosis of sex cord-stromal tumor between 2009 and 2020 from institutional archives and reviewed their cytoarchitectural features.

RESULTS

There were 25, 2, 2, and 1 cytology specimens from 19, 2, 2, and 1 patients (aged 7-90 years, median 57 years) with AGCT, JGCT, SLCT, and SCT, respectively. Features common to all SCSTs included 3-dimensional groups, rosettes, rare papillary fragments, abundant single cells and naked nuclei. Rosettes and a streaming appearance of cell groups were only seen in AGCTs, which also rarely featured eosinophilic hyaline globules and metachromatic stroma. AGCTs exhibited high nuclear:cytoplasmic (N:C) ratios, with mild nuclear pleomorphism, uniform nuclei with finely granular chromatin, nuclear grooves and small nucleoli; in contrast, other SCSTs lacked rosettes and nuclear grooves and had generally lower N:C ratios, greater nuclear pleomorphism, coarse chromatin and more abundant cytoplasm. Mitotic figures, necrosis, and inflammation were rarely identified.

CONCLUSIONS

AGCTs show cytomorphologic features that are distinct from those of other SCSTs. Careful evaluation of the cytological features and ancillary studies (eg, immunochemistry for FOXL2, inhibin and calretinin, or sequencing for FOXL2 mutations) can aid in the accurate diagnosis of these tumors.

A case of a vaginal Brenner tumor without a gland mimicking a borderline tumor: unusual morphology and diagnostic pitfalls

Brenner tumor is a rare neoplasm of the vagina. This tumor is diagnosed according to the criteria of ovarian tumors. We report here a 64-year-old postmenopausal woman with a 2.0-cm sessile vaginal polyp for 9 years. Microscopic examination showed unusual features of no gland appearing in the tumor, but the other two characteristic components of transitional islands and dense fibrous stroma were observed. The tumor was diagnosed as a vaginal Brenner tumor on the basis of the definition proposed by the World Health Organization classification of female reproductive organ tumors. In our case, part of the epithelial nests of the Brenner tumor showed basaloid cell differentiation with peripheral palisading, and irregular papillary hyperplasia was observed around the epithelial nests similar to a borderline tumor. However, no mitotic activity or nuclear atypia was present in either the epithelial or stromal components. The presence of epithelial nests requires attention in the medical history of the patient. Our patient did not have a history of primary urothelial carcinoma. Our patient’s benign vaginal Brenner tumor with different morphological characteristics supports the current notion that Walthard nests might act as possible precursor lesions.

Recurrent urothelial carcinoma-like FGFR3 genomic alterations in malignant Brenner tumors of the ovary

Malignant Brenner tumor is a rare primary ovarian carcinoma subtype that may present diagnostic and therapeutic conundrums. Here, we characterize the genomics of 11 malignant Brenner tumors, which represented 0.1% of 14,153 clinically advanced ovarian carcinomas submitted for genomic profiling during the course of clinical care. At the time of molecular profiling, there was no evidence of a primary urothelial carcinoma of the urinary tract in any case. Cases with transitional-like morphologic features in the setting of variant ovarian serous or endometrioid carcinoma morphology were excluded from the final cohort. Malignant Brenner tumors exhibited CDKN2A/2B loss and oncogenic FGFR1/3 genomic alterations in 55% of cases, respectively; including recurrent FGFR3 S249C or FGFR3-TACC3 fusion in 45% of cases. FGFR3-mutated cases had an associated benign or borderline Brenner tumor pre-cursor components, further confirming the diagnosis and the ovarian site of origin. Malignant Brenner tumors were microsatellite stable, had low tumor mutational burden and exhibited no evidence of homologous recombination deficiency. PIK3CA mutations were enriched with FGFR3 alterations, while FGFR3 wild-type cases featured MDM2 amplification or TP53 mutations. The FGFR3 S249C short variant mutation was absent in 14,142 non-Brenner, ovarian carcinomas subtypes. In contrast to malignant Brenner tumors, FGFR1/2/3 alterations were present in ~5% of non-Brenner, ovarian serous, clear cell and endometrioid carcinoma subtypes, most often as FGFR1 amplification in serous carcinoma or FGFR2 short variant alterations in clear cell or endometrioid carcinomas, respectively. Finally, malignant Brenner tumors had overall distinct genomic signatures compared to FGFR-mutated ovarian serous, endometrioid, and clear cell carcinoma subtypes. This study provides insights into the molecular pathogenesis of malignant Brenner tumors, contrasts the extent of FGFR1/2/3 alterations in ovarian serous, clear cell and endometrioid carcinomas and emphasizes the potential value of novel and FDA-approved, anti-FGFR inhibitors, such as erdafitinib and pemigatinib, in refractory, FGFR3-mutated malignant Brenner tumors.

Brenner tumor associated with rete ovarii: a histologic and immunohistochemical analysis of six cases exploring the relationship between these entities

The association of Brenner tumor (BT) with rete ovarii (RO) has been rarely alluded to in the literature. Both entities have debatable histogenesis. In this study of six cases of BT associated with RO, we describe the morphologic features and performed immunohistochemical staining for markers of Mullerian, Wolffian, mesothelial, and sex cord stromal derivation to explore the relationship between these entities. Histologically, all BTs were benign, microscopic, and incidental. RO was prominent and hyperplastic with gradual or abrupt transition to BT. In addition, focal areas of rete entrapped between BT nests were seen. All BTs were positive for GATA-3 and negative for PAX-8. Conversely, the RO in all cases was negative for GATA-3 and positive for PAX-8. WT-1 was positive in both entities. Sex cord stromal and mesothelial markers (other than WT-1) were negative in BT and RO. Although morphologically, BTs seem to arise from RO in these cases, they have a distinct immunophenotype. It is possible that at least some BTs arise from metaplastic changes in RO epithelium.

Borderline Brenner Tumor of the Ovary Coexisting With an Ovarian Mucinous Cystadenoma With Focal Atypical Epithelial Proliferation: A Rare Case With Review of the Literature

Ovarian Brenner tumors, accounting for ∼5% of overall ovarian epithelial neoplasm, are often reported in association with mucinous neoplasm. Histogenetically, the two tumors are thought to arise from similar precursors. To date, fewer than 60 borderline Brenner tumors alone have been reported, and the concomitant presence of atypical proliferative components in Brenner and mucinous tumors is even rarer. Therefore, the clinicopathological characteristics and prognosis of patients with the borderline Brenner tumors alone or coexisting with mucinous neoplasm are extremely limited. Herein, we report a unique case of a 53-year-old woman with a unilateral ovarian borderline Brenner tumor associated with focal atypical mucinous epithelial proliferation and her clinical presentations. The clinicopathological features of the tumor are documented and the literature review along with the clinical molecular advances are summarized in this study.

Multimodality Imaging Approach to Ovarian Neoplasms with Pathologic Correlation

Ovarian neoplasms can be categorized on the basis of histopathologic features into epithelial surface cell tumors, germ cell tumors, sex cord-stromal tumors, and metastases. While their imaging appearance is often nonspecific, it closely parallels the gross pathologic appearance, and radiologic-pathologic correlation is helpful to aid in a deeper understanding of the subtypes. Epithelial cell neoplasms are the most common category, and they can be benign, borderline, or malignant. Specific subtypes include serous (most common), mucinous, seromucinous, endometrioid, clear cell, Brenner, and undifferentiated. High-grade serous cystadenocarcinoma accounts for the majority of malignant ovarian tumors and the most ovarian cancer deaths. While serous neoplasms are often unilocular and bilateral, mucinous neoplasms are larger, unilateral, and multilocular. Solid components, thickened septa, and papillary projections, particularly with vascularity, indicate borderline or malignant varieties. Endometrioid and clear cell carcinomas can arise within endometriomas. Fibrous tumors (cystadenofibroma, adenofibroma, fibroma or fibrothecoma, and Brenner tumors) demonstrate low T2-weighted signal intensity of their solid components, while teratomas contain lipid. The nonspecific imaging appearance of additional malignant ovarian germ cell tumors can be narrowed with tumor marker profiles. Sex cord-stromal tumors are often solid, and secondary signs from their hormonal secretion can be a clue to their diagnosis. The authors review the anatomy of the ovary and distal fallopian tube, the proposed origins of the histologic subtypes of tumors, the clinical features and epidemiology of ovarian neoplasms, and the applications of US, CT, and MRI in imaging ovarian neoplasms. The main focus is on the radiologic and pathologic features of the multiple ovarian neoplasm subtypes. An algorithmic approach to the diagnosis of ovarian neoplasms is presented. Online supplemental material is available for this article. ^©RSNA, 2020.

[Borderline ovarian tumours: CNGOF Guidelines for clinical practice - Biopathology of ovarian borderline tumors]

OBJECTIVES

Ovarian borderline tumors (OBT) represent a heterogeneous group of lesions with specific management for each histological subtype. Thus, the correct histological diagnosis is mandatory.

MATERIAL AND METHODS

References were searched by PubMed from January 2000 to January 2018 and original articles in French and English literature were selected.

RESULTS AND CONCLUSIONS

OBT should be classified according to the last WHO classification. Any micro-invasion (foci<5mm) or microcarcinoma (foci<5mm with nuclear atypia and desmoplastic stromal reaction) should be indicated in the pathology report. In case of serous OBT, variants (classical or the micropapillary/cribriform) should be indicated (grade C). The peritoneal implants associated with OBT, should be classified as invasive or noninvasive, according to the extension into the underlying adipous tissue. If no adipous tissue is seen the term undetermined should be used (grade B). In case of mucinous OBT bilateral and/or with peritoneal implants or peritoneal pseudomyxoma a search for primitive gastrointestinal, appendiceal or biliopancreatic tumor should be performed (grade C). In case of OBT, a thorough sampling of the tumor is recommended, with 1 block/cm and 2 blocks/cm in case of mucinous OBT, serous OBT micropapillary variant, OBT with intraepithelial carcinoma or/and micro-invasion. Peritoneal implants should be examined in toto. Omentum without macroscopic lesion should be sampled in 4 to 6 blocks (grade C). In case of ovarian cyst suspicious for OBT, fine needle aspiration is not recommended (grade C). In case of ovarian tumor suspicious for OBT, intraoperative examination should be performed by a gynecological pathologist (grade C).

Amplification of MDM2 and Loss of p16 Expression: Do They Have a Role in Malignant Transformation of Ovarian Brenner Tumor?

OBJECTIVES

To review the significance of MDM2 and cyclin D1 expression and loss of p16 expression in malignant and borderline Brenner tumors (BTs) of the ovary.

METHODS

We describe 2 new cases of ovarian BT, 1 malignant and 1 borderline. We studied MDM2, p16, and cyclin D1 expression by immunohistochemistry in the benign, borderline, and malignant components of these 2 cases and in 5 additional cases of benign BT. We also reviewed and summarized the literature on the clinical, immunohistochemical and molecular characteristics of borderline and malignant BTs (BdBTs and MBTs).

RESULTS

Nuclear expression of MDM2 was seen only in the MBT. Loss of p16 expression was seen in both BdBT and MBT. Cyclin D1 expression was in proportion to the degree of malignancy. Amplification of MDM2, loss of CDKN2A (p16-encoding gene), and amplification of CCND1 (cyclin D1-encoding gene) were confirmed by commercial next-generation sequencing in the case of MBT.

CONCLUSIONS

We are the first to report immunohistochemical expression of MDM2 in an MBT. Amplification of MDM2 and loss of p16 expression may have a role in malignant transformation of BT.

Prevalence of endosalpingiosis and other benign gynecologic lesions

Endosalpingiosis, traditionally regarded as an incidental pathological finding, was recently reported to have an association with gynecologic malignancies. To determine the prevalence of endosalpingiosis, we evaluated all benign appearing adnexal lesions using the Sectioning and Extensively Examining-Fimbria (SEE-Fim) protocol, and queried the pathology database for the presence of endosalpingiosis, gynecologic malignancy, endometriosis, Walthard nests, and paratubal cysts. Using the SEE-Fim protocol, the prevalence of endosalpingiosis, endometriosis, Walthard nests, and paratubal cysts were 22%, 45%, 33%, and 42% respectively, substantially higher than previously reported. All lesions were observed to increase with age except endometriosis which increased until menopause then decreased dramatically. Among specimens including ovarian tissue, the prevalence of implantation of at least one lesion type was ubiquitous in patients age 51 and older (93%). The clinical significance of endosalpingiosis should be a continued area of research with larger trials assessing prevalence, factors affecting incidence, and association with malignancy. Our findings contribute to elucidating the origin of ectopic lesions and gynecologic disease risk.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Extraovarian Brenner tumor in the uterus: a case report and review of literature

BACKGROUND

Extraovarian Brenner tumors (EOBTs) are extremely rare and can be observed incidentally in both female and male patients, raising concerns regarding the origin of Brenner tumors.

CASE PRESENTATION

A 53-year-old postmenopausal woman presented with a nodular lesion in the left side of the corpus uteri, which was found at a routine health check. Macroscopically, the lesion appeared as a solid nodule with a yellowish-gray cut surface, approximately 6 cm in greatest diameter. Microscopically, the lesion consisted of well-defined epithelial nests and spindled stromal cells. Parenchymal cells expressed CK7, GATA3, CK5/6, 34βE12, and p63. A single layer of cavity-lined cells with umbrella-like shape showed apical Uroplakin III positivity. Stromal cells were positive for SMA, ER, and PR. The final diagnosis was EOBT and the patient was followed for 2 months with no recurrence.

CONCLUSIONS

We report here the third case of EOBTs in the uterus. The combination of morphologic and immunohistochemical results supported the involvement of urothelial metaplasia in the development of EOBTs. The similarities between EOBTs and Walthard nests made Müllerian epithelium an attractive candidate as the cellular origin. Changes of tissue structure or sex hormones imbalance may lead to the translocation of Müllerian remnants to distant organs, explaining the pathogenesis of EOBTs.

Ovarian borderline tumors in the 2014 WHO classification: evolving concepts and diagnostic criteria

Borderline ovarian tumors (BOT) are uncommon but not rare epithelial ovarian neoplasms, intermediate between benign and malignant categories. Since BOT were first identified >40 years ago, they have inspired controversies disproportionate to their incidence. This review discusses diagnostic criteria for the histologic subtypes of BOT, highlighting areas of diagnostic challenges, ongoing controversies, and changes in terminology implemented by the recent 2014 WHO Classification of Tumours of the Female Genital Organs. Emerging knowledge supports the notion that subtypes of borderline ovarian tumors comprise distinct biologic, pathogenetic, and molecular entities, precluding a single unifying concept for BOT. Serous borderline tumors (SBT) share molecular and genetic alterations with low-grade serous carcinomas and can present at higher stages with peritoneal implants and/or lymph node involvement, which validates their borderline malignant potential. All other (non-serous) subtypes of BOT commonly present at stage I confined to the ovary(ies) and are associated with overall survival approaching that of the general population. An important change in the WHO 2014 classification is the new terminology of non-invasive implants associated with SBT, as any invasive foci (previously called “invasive implants”) are now in line with their biological behavior considered peritoneal low-grade serous carcinoma (LGSC). The controversy regarding the terminology of non-serous borderline tumors, called by some pathologists “atypical proliferative tumor” in view of their largely benign behavior, has not been resolved. The concepts of intraepithelial carcinoma and microinvasion may evolve in further studies, as their presence appears to have no prognostic impact and is subject to considerable inter-observer variability.

Brenner tumor of the testis: A case report and review of the literature

Brenner tumor is a rare type tumor, which mainly develops in the ovaries and rarely in the adnexal region and urinary system. To the best of our knowledge, only 5 cases of testicular Brenner tumor have been reported to date. In this report, we present the case of a 55-year-old patient who noted a swelling of the right scrotum for ~20 days. The clinical suspicion was an epididymal cyst. However, following surgical resection and subsequent pathological examination, the mass was diagnosed as a testicular Brenner tumor. A supplementary review of previously published cases and literature is also presented. The aim of this report is to help elucidate this disease and reduce the rate of clinical and pathological misdiagnosis.

Molecular Genetic Analysis of Ovarian Brenner Tumors and Associated Mucinous Epithelial Neoplasms: High Variant Concordance and Identification of Mutually Exclusive RAS Driver Mutations and MYC Amplification

Benign ovarian Brenner tumors often are associated with mucinous cystic neoplasms, which are hypothesized to share a histogenic origin and progression, however, supporting molecular characterization is limited. Our goal was to identify molecular mechanisms linking these tumors. DNA from six Brenner tumors with paired mucinous tumors, two Brenner tumors not associated with a mucinous neoplasm, and two atypical proliferative (borderline) Brenner tumors was extracted from formalin-fixed, paraffin-embedded tumor samples and sequenced using a 358-gene next-generation sequencing assay. Variant calls were compared within tumor groups to assess somatic mutation profiles. There was high concordance of the variants between paired samples (40% to 75%; P < 0.0001). Four of the six tumor pairs showed KRAS hotspot driver mutations specifically in the mucinous tumor. In the two paired samples that lacked KRAS mutations, MYC amplification was detected in both of the mucinous and the Brenner components; MYC amplification also was detected in a third Brenner tumor. Five of the Brenner tumors had no reportable potential driver alterations. The two atypical proliferative (borderline) Brenner tumors both had RAS mutations. The high degree of coordinate variants between paired Brenner and mucinous tumors supports a shared origin or progression. Differences observed in affected genes and pathways, particularly involving RAS and MYC, may point to molecular drivers of a divergent phenotype and progression of these tumors.

Clonality analysis of combined Brenner and mucinous tumours of the ovary reveals their monoclonal origin

The derivation of ovarian intestinal-type mucinous tumours is not well established. Some are derived from teratomas but the origin of the majority is not clear. It has been recently proposed that the non-germ cell group may be derived from Brenner tumours, as the association of a mucinous tumour with a Brenner tumour is frequently observed. In order to explore the histogenesis of these neoplasms, we undertook a clonality analysis of the two components of ten combined Brenner and mucinous tumours using a human androgen receptor gene (HUMARA) assay. All eight informative cases of ten showed a concordant X-chromosome inactivation pattern between the two tumour components, indicative of a shared clonal origin (p = 0.0039). Microsatellite genotyping in five of the combined tumours displayed an identical heterozygous pattern with paired Fallopian tube tissue, indicative of a somatic cell origin. In addition, paired box protein 8, a highly sensitive Müllerian epithelial marker, was not detected by immunohistochemistry in either tumour component in any of the ten tumours, suggesting that this subset of mucinous tumours does not originate from Müllerian-derived epithelium. In conclusion, this study demonstrates that in combined mucinous and Brenner tumours, there is a shared clonal relationship between the two different tumour components and suggests that some pure mucinous tumours may develop from a Brenner tumour in which the Brenner tumour component becomes compressed and obliterated by an expanding mucinous neoplasm.

Different staining patterns of ovarian Brenner tumor and the associated mucinous tumor

The association of ovarian Brenner tumors and adjacent mucinous tumors is well known but not completely understood. In this study, we analyzed immunohistochemical markers on Brenner tumors and their associated mucinous tumor to explore Mullerian as well as Wolffian and germ cell derivation and determine if the mucinous component is independent or related to the Brenner tumor. Of 32 consecutive cases of Brenner tumors, 8 were identified with significant mucinous component, and 7 additional cases included foci of mucinous epithelium within the Brenner transitional nests. All Brenner tumors were diffusely positive for GATA3 and negative for Paired box gene 8, PAX2, and Sal-like protein 4. Interestingly, the areas of mucinous epithelium as well as mucinous tumors, intermixed and adjacent to the Brenner tumor, were negative for all 4 markers; however, occasional basal-like cells retained expression of GATA3. The immunoprofile of mucinous tumors associated with Brenner tumors shares the lack of Mullerian markers PAX2 and Paired box gene 8 with the Brenner tumor but differs in the expression of GATA3 only in the Brenner tumor component.