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Borderline Brenner tumors (BBT) have a range of morphology that shows considerable overlap with that of malignant Brenner tumors (MBT). In particular, two histological patterns of BBT can be particularly challenging: 1) BBT with intraepithelial carcinoma (BBT-IEC) and 2) BBT with a small nested pattern (BBT-SNP). BBT-IEC is characterized by a tumor with the low-power non-infiltrative silhouette of a conventional BBT, but with increased cytological atypia and mitotic activity similar to that of MBT. Conversely, BBT-SNP is characterized by a complex proliferation of small tumor nests that closely resemble the infiltrative growth pattern of MBT, but without the obligate cytologic atypia and mitotic activity of MBT. We suggest that the combination of p16, p53 and Ki-67 may be helpful in distinguishing these 2 patterns of BBT from both conventional BBT and from MBT. While both conventional BBT and BBT-IEC show a null pattern of p16 expression, our case of BBT-IEC showed aberrant p53 overexpression, albeit with a maturation pattern similar to that described for TP53 mutant mucinous ovarian carcinoma and differentiated vulvar intraepithelial neoplasia (dVIN). Similarly, while BBT-SNP shows an infiltrative-like growth pattern similar to that of MBT, our case also showed a wild-type pattern of p53 expression and a Ki-67 proliferative index similar to areas with conventional BBT histology. In conclusion, in our small case series, we show that the use of immunohistochemistry for p53 and Ki-67 may help to distinguish challenging patterns of BBT from MBT. Further studies are needed to validate this finding in a larger case cohort., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: To explore the clinical characteristics of ovarian Brenner tumors and provide some basis for the treatment regimen of ovarian Brenner tumors., Methods: A retrospective analysis of the pathology database of surgical specimens at the Huzhou Maternal and Child Health Hospital from September 2008 to February 2023 was conducted. Patients who were pathologically diagnosed with ovarian Brenner tumors were included. Clinical data of patients was collected, and their diagnostic and treatment characteristics were summarized and analyzed., Results: A total of 20 cases were included in this study, all of which were histologically confirmed by surgical pathology. Among them, 8 cases (40%) were combined with serous, mucinous cystadenoma, or simple cyst. One case presented with a benign ovarian Brenner tumor combined with mucinous cystadenoma, underwent right adnexectomy, and relapsed 5 years later as a malignant Brenner tumor (MBT) coexisting with ovarian squamous cell carcinoma. Multiple tumor markers were elevated malignantly, with CA199 being the most significant. Treatments included unilateral adnexectomy in 7 cases, bilateral adnexectomy in 3 cases, total hysterectomy with bilateral adnexectomy in 7 cases, radical hysterectomy in 1 case, and 2 cases underwent ovarian staging surgery. MBT patients received three cycles of postoperative chemotherapy with the carboplatin-paclitaxel (TC) regimen., Follow-Up: One case with concomitant cervical cancer was lost to follow-up after surgery in an external hospital; one case with concomitant ovarian cancer received no further treatment after surgery and was lost to follow-up after 2 years; one case with concomitant endometrial cancer received no further treatment after surgery, and had no recurrence after 4 years of follow-up. Regular follow-up for MBT patients continued for 5 years without recurrence. The remaining 16 cases were followed up for a period ranging from 6 months to 7 years, with no reported recurrences., Conclusion: Clinical manifestations and auxiliary examinations of ovarian Brenner tumors lack obvious specificity. When necessary, a combination of tumor markers and imaging examinations can aid in diagnosis. Surgical strategies should be selected according to the patient's menopausal status., Trial Registration: Not applicable., (© 2024. The Author(s).)

Ovarian Brenner tumor with abnormally increased serum carbohydrate antigen 19-9 (CA19-9) level is extremely rare. A 70-year-old woman with abnormally elevated serum CA199 (1289 U/ml) found in routine physical examination. Pelvic CT and MRI scan revealed a large mass with large patches of calcification in the right adnexal area, and the patient achieved total hysterectomy and bilateral adnexectomy. Grossly, the right ovary had a solid enlargement of about 7.0 cm × 6.0 cm × 5.0 cm with irregular nodules and smooth surface and the cut surface of the mass showed that the tumor is cystic and solid. Microscopically, the tumor showed a background of fibrous tissue hyperplasia with nested and adenoid cell clusters with uniform cell size and clear boundaries. The cells were translucent with eosinophilic cytoplasm and calcification. Immunohistochemical staining showed CK7, CA125, and P63 presented diffusely strongly positive staining, while negativity for CK20, GATA3, AR, P53, and CgA. Ki-67 showed weak positive staining, about 1%. The serum CA199 level decreased significantly on the 5th day after surgery. Postoperative pathology and immunohistochemistry confirmed borderline Brenner tumor. This is the first to report a case of borderline Brenner tumor with an abnormally high serum level of CA199 before surgery. In clinical practice, the possibility of ovarian Brenner tumor should be considered when abnormal elevation of serum CA199 level cannot be reasonably explained., (© 2022. The Author(s), under exclusive licence to Royal Academy of Medicine in Ireland.)

Purpose: To describe the clinical and sonographic features of ovarian benign Brenner tumor (BBT) and malignant Brenner tumor (MBT), and to compare performance of four diagnostic models in differentiating them., Methods: Fifteen patients with BBTs and nine patients with MBTs were retrospectively identified in our institution from January 2003 and December 2021. One ultrasound examiner categorized each mass according to ovarian-adnexal reporting and data system (O-RADS), international ovarian tumor analysis (IOTA) Simple Rules Risk (SR-Risk) assessment and assessment of different neoplasias in the adnexa (ADNEX) models with/without CA125. Receiver operating characteristic curves were generated to compare diagnostic performance., Results: Patients with MBT had higher CA125 serum level (62.5% vs. 6.7%, P = 0.009) and larger maximum diameter of lesion (89 mm vs. 43 mm, P = 0.009) than did those with BBT. BBT tended to have higher prevalence of calcifications (100% vs. 55.6%, P = 0.012) and acoustic shadowing (93.3% vs. 33.3%, P = 0.004), and lower color scores manifesting none or minimal flow (100.0% vs. 22.2%, P < 0.001). Areas under curves of O-RADS, IOTA SR-Risk and ADNEX models with/without CA125 were 0.896, 0.913, 0.892 and 0.896, respectively. There were no significant differences between them., Conclusion: BBTs are often small solid tumors with sparse color Doppler signals, which contain calcifications with posterior acoustic shadowing. The most common pattern of MBT is a large multilocular-solid or solid mass with irregular tumor borders, and most were moderately or richly vascularized at color Doppler. These four models have excellent performance in distinguishing them., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

BACKGROUND Ovarian cancer is the leading cause of death in women with gynecological cancers. Ovarian Brenner tumor (BT) is an extremely rare type of epithelial ovarian cancer that accounts for about 1-3% of all ovarian cancers. Herein, we report a rare case of ruptured malignant ovarian Brenner tumor. CASE REPORT A 39-year-old P0A0 woman came to the Emergency Department (ED) with abdominal pain and tenderness. Perforated appendicitis was initially suspected and an emergency laparotomy was performed by the General Surgery Department. Then, a 25×20×15 cm grayish cystic mass originating from the right adnexa was found. We consulted intraoperatively with the Gynecology Oncology Department and decided to perform complete surgical staging. Histopathological examination confirmed the diagnosis of malignant Brenner tumor (MBT). The patient was then given adjuvant chemotherapy with a paclitaxel carboplatin regimen. In this case report, we present our case along with a review of the current literature regarding the diagnosis and therapy of malignant Brenner tumor. CONCLUSIONS Ovarian MBT is an extremely rare ovarian cancer. Diagnosing MBT can be challenging as there are no clinical, laboratory, or imaging features typical for it. Surgery is the mainstay treatment in MBT cases. The role of adjuvant chemotherapy in MBT is still being debated.

Brenner tumors (BTs) are surface-epithelial stromal cell tumors that are categorized by the World Health Organization as benign, borderline, and malignant. Due to the rarity of BTs, the published literature on these tumors is comprised primarily of case reports and small retrospective studies. We performed a pathology database review spanning the last ten years at our institution revealing nine reported benign BTs. We collected the clinical and pathological data of patients associated with those BTs, describing the clinical presentation and imaging results, and assessing the possible risk factors associated with them. The average age at diagnosis was 58 years. BTs were discovered incidentally in 7/9 cases. The tumor was multifocal and bilateral in 1/9 cases and ranged in size from 0.2 cm to 7.5 cm. Associated Walthard rests were found in 6/9 cases and transitional metaplasia of surface ovarian and/or tubal epithelium was found in 4/9 cases. One patient had an associated mucinous cystadenoma in the ipsilateral ovary. Another patient had an associated mucinous cystadenoma in the contralateral ovary. In conclusion, we found that Walthard rests and transitional metaplasia are common findings in association with BTs. Additionally, pathologists and surgeons need to be aware of the association between mucinous cystadenomas and BTs.

Brenner's tumour of the ovary is a rare diagnosis that is usually incidental in either clinical finding or laparotomy. Pathologically, it can be classified as being an uncommon surface epithelial tumour. Originally known as a transitional cell tumour due to its histological similarity to the urothelium, Brenner is usually an unilateral and benign tumour. The site of incidence is predominantly the ovary and can very rarely occur in other locations including the testis. The following is a case of Brenner's tumour of the ovary in a postmenopausal woman after surgical treatment, the features of which will be discussed briefly., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Brenner tumors are uncommon ovarian neoplasms, most of which are benign, although borderline and malignant variants occur. We report 2 unusual ovarian neoplasms composed of an admixture of typical benign Brenner tumor and a low-grade epithelial neoplasm which we designate as low-grade basaloid carcinoma. The latter component morphologically and immunohistochemically resembled "salivary gland-type/myoepithelial" neoplasms with variable positive staining with cytokeratins, p63, S100, and CD117. One tumor exhibited aggressive behavior with local recurrence and distant metastasis. This neoplasm exhibited focal "high-grade" transformation with diffuse mutation-type p53 staining, in contrast to the wild-type immunoreactivity in the low-grade component. As far as we are aware, such neoplasms have not previously been reported in the literature and this represents a newly described morphologic variant of malignant Brenner tumor., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 by the International Society of Gynecological Pathologists.)

Brenner tumors are rare ovarian neoplasms composed of ovarian transition cells surrounded by dense fibrous tissue. Most of them are small tumors (<2 cm), detected incidentally in asymptomatic women. Its predominantly fibrous content results in relatively low signal on T 2 weighted images, establishing differential diagnosis with ovarian fibroma and thecoma. Their imaging features are very similar, the differentiation is based on secondary characteristics, such as signs or symptoms of estrogen excess and the presence of a second ovarian neoplasm, which has been reported in up to 30% of patients with Brenner tumor. Although originally thought to be universally benign, there have been scattered reports in the past decades of borderline and malignant forms of Brenner tumors.

Malignant Brenner tumor (MBT) is diagnosed in the setting of invasive high-grade carcinoma with urothelial-like morphology and the presence of an adjacent benign Brenner tumor (BBT) or borderline Brenner tumor (BLBT). MDM2 amplification was recently detected by next-generation sequencing on a small number of MBTs, potentially significant for future targeted therapy. Experience is limited, however, and evaluation of widely available MDM2 immunohistochemistry (IHC) has not been performed to determine clinical utility. After confirming all diagnoses morphologically and immunohistochemically, we performed MDM2 IHC on 4 MBTs, 3 BLBTs, 26 BBTs, 142 high-grade serous carcinomas (HGSC), 6 ovarian endometrioid carcinomas (OEC) with urothelial-like morphology, and 49 high-grade urothelial carcinomas (HGUC). MDM2 IHC was considered positive with diffuse (>25%) nuclear reactivity; in cases of patchy staining (10-25% nuclear reactivity), MDM2 was considered equivocal. Positive staining in <10% of cells was considered negative. In cases with positive or equivocal staining, MDM2 amplification was evaluated by fluorescence in-situ hybridization (FISH). Three MBTs (75%) showed diffuse nuclear reactivity for MDM2 by IHC, a finding corroborated by amplification of MDM2 in all three cases. One MBT and 2 BLBTs showed equivocal MDM2 IHC, but all three were negative for MDM2 amplification. The final BLBT, as well as all BBTs, HGSC, OEC, and HGUC, were negative for MDM2. In conclusion, our limited cohort confirms MDM2 amplification in MBT and suggests that MDM2 IHC may have an influence in rare diagnostically challenging cases., (Copyright © 2021. Published by Elsevier Inc.)

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.

Supernumerary ectopic ovaries are very rare, with fewer than 40 cases of isolated supernumerary ovaries reported in the literature since their discovery in 1864. Tumors arising in ectopic ovaries are also extremely rare, with only a handful of reports in the literature. Given the rarity of this combination of findings, we report a case of a 68-yr-old woman incidentally found to have a 4.7 cm solid retroperitoneal mass adjacent to the liver, diagnosed as a benign Brenner tumor arising in a supernumerary ectopic ovary. To our knowledge, there has been only one previously reported case of Brenner tumor arising in this unusual setting., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 by the International Society of Gynecological Pathologists.)

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., (Copyright © 2021 Elsevier Inc. All rights reserved.)

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.

A rare case of malignant Brenner tumour of ovary manifesting with intestinal perforation due to colonic infiltration is elaborated in the present report. Brenner's tumour accounts for 1%-2% of all ovarian neoplasms and malignant Brenner tumour is even rarer and only about 5% of Brenner tumours are malignant. A 62-year-old woman came to surgical emergency with 1-month history of abdominal pain, vomiting and constipation with a palpable mass in right iliac fossa. Abdominal radiograph was suggestive of colonic obstruction. Contrast-enhanced CT of the abdomen revealed cystic right ovarian mass of 10.2×8.8 cm 2 with pneumoperitoneum. Exploratory laparotomy was done, which revealed mass arising from right ovary involving terminal ileum, cecum and ascending colon. Possibility of ovarian malignancy was kept. Patient underwent debulking surgery along with ileostomy and descending colon mucous fistula was created. Histology was compatible with malignant Brenner tumour of the ovary., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

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., (© American Society for Clinical Pathology, 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The origin of primary mucinous ovarian tumors is unknown. We explore the hypothesis that they originate from either Brenner tumors or teratomas and examine differences between the tumors that arise in these settings. A total of 104 Brenner tumor-associated mucinous tumors and 58 teratoma-associated mucinous tumors were analyzed. Immunohistochemistry for 21 antigens and fluorescence in situ hybridization for ERBB2 and MYC were performed. Genome-wide copy number analysis and mutation analysis for 56 cancer-related genes was carried out on a subset of mucinous ovarian tumors and their complementary Brenner tumor or teratoma. Patients with teratoma-associated mucinous tumors were significantly younger than patients with Brenner tumor-associated mucinous tumors (43 vs. 61 years). During progression from cystadenoma to atypical proliferative mucinous (borderline) tumor to carcinoma expression of typical gastrointestinal markers was increased in both Brenner tumor-associated and teratoma-associated mucinous tumors. Brenner tumor-associated mucinous tumors showed more frequently calcifications and Walthard cell nests, rarely expressed SATB2 and showed more often co-deletion of CDKN2A and MTAP. Teratoma-associated mucinous tumors were characterized by mucinous stromal dissection, SATB2 expression and RNF43 mutations. Other frequent mutations in both Brenner tumor-associated and teratoma-associated mucinous tumors were TP53 and KRAS mutations. Based on identical mutations or copy number profiles clonal relationships were indicated in two mucinous tumors and their associated Brenner tumor. Teratomas and Brenner tumors give rise to different subtypes of mucinous ovarian tumors. Subsequent progression pathways are comparable since both Brenner tumor-associated and teratoma-associated mucinous tumors develop a gastrointestinal immunophenotype during progression and show early mutations in KRAS and TP53. Teratoma-associated mucinous tumors may more closely resemble true gastrointestinal tumors, indicated by their expression of SATB2 and the presence of RNF43 mutations.

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.

The group of rare malignant ovarian tumors includes the group of germ cell tumors, sex cords stromal ovarian tumors, small cell carcinoma, malignant Brenner tumors, rare epithelial tumors such as mucinous carcinoma, clear cell carcinoma, or low-grade serous carcinoma, as well as ovarian carcinosarcoma. Together they comprise about 10% of all ovarian tumors. Due to their low prevalence and their heterogeneity, data and treatment recommendations are limited. Even though all ovarian tumors are staged according to the FIGO staging of epithelial ovarian tumors, treatment differs especially in germ cell tumors and sex cords stromal ovarian tumors. Non-epithelial ovarian tumors can arise from a variety of ovarian precursor cells such as germ cells, granulosa cells, theca cells, or stromal fibroblasts. As can be expected already due to their divergent precursor lesions, these malignancies are substantially different but united by their rarity. This overview article gives a comprehensive summary on the pathology and clinical presentation, as well as therapy recommendations of a selection of those rare ovarian tumors, based on the latest national guidelines and related important publications., (Copyright © 2020 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Brenner tumors are uncommon ovarian neoplasms which occasionally occur in combination with a mucinous tumor. Rarely, the combination of Brenner tumor and thyroid tissue (struma ovarii) has been reported. We report an ovarian neoplasm with components of Brenner tumor, mucinous cystadenoma and struma ovarii. As far as we are aware, this combination has not been previously reported. We speculate on the possible histogenesis of this combination of elements.

Brenner tumors arise from ovarian epithelium, accounting for approximately 5% of benign ovarian epithelial tumors. The World Health Organization classification groups them into benign, borderline, and malignant on the basis of proliferation and invasiveness, and borderline Brenner tumor is defined as "displaying epithelial proliferation beyond that seen in benign Brenner's tumor, but lacking stromal invasion." Borderline Brenner tumors are rare. Fewer than 60 cases have been reported. The more recent articles mostly focus on pathogenesis. We reviewed the literature on borderline Brenner tumor and have summarized the clinical and pathologic findings, as well as the treatment, differential diagnoses, and recent advances in histogenesis and molecular pathogenesis.

Synchronous tumours of two different histological type are not uncommon in the female genital tract. But triple synchronous tumours of three or more different histological types is extremely rare. We describe a case of a 48-year-old female patient who presented with cervical growth and bilateral ovarian masses. Pathological evaluation of the surgical specimen revealed synchronous cervical squamous cell carcinoma, right ovarian dermoid cyst and left ovarian benign Brenner tumour. The patient was treated as per the carcinoma cervix protocol and is disease free at 1-year follow-up. To our knowledge this is the first report of such an occurrence. This occurrence cannot be related to any known hereditary syndromes, hence may be considered a chance association. Although rare, awareness of such an occurrence is important for the surgeon, radiologist and the surgical pathologist for proper diagnosis and management., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Mucinous neoplasms of the ovary account for 10%-15% of ovarian neoplasms. They may be benign, borderline, or malignant. The large majority are benign or borderline, accounting for 80% and 16%-17%, respectively. Mucinous neoplasms of the ovary most commonly affect women in their 20s to 40s. The clinical manifestation is nonspecific, but most mucinous ovarian neoplasms manifest as large unilateral pelvic masses. At gross pathologic analysis, mucinous ovarian neoplasms appear as large multiloculated cystic masses. The contents of the cyst loculi vary on the basis of differences in internal mucin content. At histologic analysis, mucinous ovarian neoplasms are composed of multiple cysts lined by mucinous epithelium, often resembling gastrointestinal-type epithelium. Imaging evaluation most commonly includes US and/or MRI. The imaging findings parallel the gross pathologic features and include a large, unilateral, multiloculated cystic mass. The cyst loculi vary in echogenicity, attenuation, and signal intensity depending on the mucin content. Mucinous neoplasms of the ovary are staged surgically using the FIGO (International Federation of Gynecology and Obstetrics) staging system. Primary treatment is surgical, with adjuvant chemotherapy considered in the uncommon case of mucinous carcinoma with extraovarian disease. Since most mucinous ovarian neoplasms are benign or borderline, the overall prognosis is excellent.

Aim: To investigate clinicopathological parameters and histotype-specific survival of epithelial ovarian cancer by stage using the 2014 WHO classification. Patients & methods: Patients were obtained from the SEER database. Multivariate and univariate Cox regression analyses were applied to assess survival outcomes. Results: Irrespective of stages, low-grade serous and endometrioid had the best survival rates. In localized and regional stages, the poorest survival rates were detected for carcinosarcoma and malignant Brenner tumors, but in distant stage, the worst prognoses were observed in mucinous, clear cell and carcinosarcoma (p < 0.05 for all). Conclusion: Our study displayed significant differences in clinicopathological parameters and histotype-specific survival by stages that reflected current consensus on histotype classification and pathogenesis of epithelial ovarian cancer.

Rationale: Ovarian mucinous tumor with malignant mural nodule is exceedingly rare. We report a case of ovarian mucinous cystic tumor associated with sarcomatous mural nodule and benign Brenner tumor and accompanied by nodular histiocytic aggregates in the greater omentum., Patient Concerns: A 60-year-old postmenopausal woman was presented with a history of one month of lower abdominal discomfort, abdominal distension, nausea, and vomiting. A physical examination revealed a hard, palpable mass with mild tenderness in her right lower abdomen., Diagnoses: The mucinous tumor was solid and cystic and contained benign, borderline, and malignant elements. Within the solid areas, two nodules representing pleomorphic undifferentiated sarcoma and benign Brenner tumor were identified. The diagnosis of malignant mural nodule was based on vascular invasion and marked nuclear atypia, including atypical mitoses and mitotic activity., Interventions: Bilateral salpingo-oophorectomy and partial omentectomy were performed. Malignant cells were not found on cytologic examination of the peritoneal washing fluid. The patient underwent three cycles of chemotherapy with 210 mg paclitaxel liposome via an intravenous drip, 20 mg nedaplatin via an intravenous drip, and 80 mg nedaplatin via intraperitoneal perfusion., Outcomes: The patient has been followed up for 3 years without evidence of tumor recurrence and metastasis., Lessons: Careful classification of a mural nodule is important to triage patients in need of aggressive adjuvant treatment.

A combination of ovarian tumors with the same histogenetic origin but different histologic subtype is relatively common, whereas a co-occurrence of tumors with different histogenetic origin is rare. We report a case of mixed ovarian tumor composed of Brenner tumor and adult-type granulosa cell tumor, a combination that to the best of our knowledge has not been reported in the literature until now.

Objectives: To describe the ultrasound features of benign Brenner tumor in the background of complex clinical and histopathological pictures., Material and Methods: We retrospectively identified patients with histologically confirmed benign Brenner tumor of the ovary who were treated in our institution in 2003-2016, and for whom complete imaging, clinical, perioperative and histopathological data were available in the database. Ultrasound findings were drawn from images and reports using terms and definitions of the International Ovarian Tumor Analysis group and pattern recognition description was applied., Results: Twenty-three patients were identified, most postmenopausal and asymptomatic. On ultrasound, 19/23 tumors were found unilaterally, 4/23 bilaterally, and 82% of tumors were detected in the left ovary. Most Brenner tumors (16/23) contained solid components and revealed no or minimal blood flow by subjective color score upon Doppler examination (19/23, 83%). Calcifications with shadowing were observed in 57% of all Brenner tumors and in 81% of tumors containing solid components. The complex appearance of the tumor misled the sonographers to describe the mass as malignant in 9 cases (39%), and frozen section was performed perioperatively. Surgery was performed via laparoscopy in 11 (48%) and via laparotomy in 12 (52%) cases., Conclusions: The complexity of the ultrasound picture, consisting of features like calcifications with acoustic shadowing, a poorly vascularized solid mass, and a left-sided localization could be signs of a benign Brenner tumor and could preop-eratively help to differentiate between benign and malignant tumor.

Brenner tumors (BT) are rare ovarian tumors encompassing benign, borderline, and malignant variants. While the histopathology of BTs and their clinical course is well described, little is known about the underlying genetic defects. We employed targeted next generation sequencing to analyze the mutational landscape in a cohort of 23 BT cases (17 benign, 2 borderline, and 4 malignant) and 3 ovarian carcinomas with transitional cell histology (TCC). Copy number variations (CNV) were validated by fluorescence in-situ hybridization (FISH) and quantitative PCR-based copy number assays. Additionally, we analyzed the TERT promotor region by conventional Sanger sequencing. We identified 25 different point mutations in 23 of the analyzed genes in BTs and 10 mutations in 8 genes in TCCs. About 57% percent of mutations occurred in genes involved in cell cycle control, DNA repair, and epigenetic regulation processes. All TCC cases harbored TP53 mutations whereas all BTs were negative and none of the mutations observed in BTs were present in TCCs. CNV analysis revealed recurrent MDM2 amplifications in 3 out of 4 of the malignant BT cases with one case harboring a concomitant amplification of CCND1. No mutations were observed in the TERT promoter region in BTs and TCCs, which is mutated in about 50%-75% of urothelial carcinoma and in 16% of ovarian clear-cell carcinomas. In conclusion, our study highlights distinct genetic features of BTs, and detection of the triplet phenotype MDM2 amplification/TP53 wt/TERT wt may aid diagnosis of malignant BT in difficult cases. Moreover, selected genetic lesions may be clinically exploitable in a metastatic setting., (© 2017 Wiley Periodicals, Inc.)

Rationale: Adnexal torsion is 1 of the most common emergency gynecological disease. It is more often diagnosed in reproductive age, but rarely in postmenopausal women. The clinical symptoms of adnexal torsion are nonspecific in postmenopausal women. Epithelial ovarian tumors are common in adults, and the risk of malignancy increases with age, especially after menopause. So, it is difficult to diagnose adnexal torsion precisely compared with reproductive women, and most cases of adnexal torsion with postmenopausal women are diagnosed as a malignancy preoperatively. We report a case of ovarian torsion with mixed epithelial tumor misdiagnosed as a malignancy in postmenopausal woman., Patient Concerns: A 65-year-old woman presented lower left abdominal pain, and there was slight abdominal distension, but no tenderness or rebound tenderness on abdominal palpation., Diagnoses: Radiologic assessments showed a huge multiseptated cystic mass with solid portion in the left ovary, and malignancy was suspected. The test for serum tumor markers revealed normal levels of cancer antigen 125 (CA-125)., Interventions: The patient underwent a laparotomy and there was torsion of the left ovary. We conducted frozen biopsy of left ovary for confirming malignancy before performing staging surgery., Outcomes: The result of a frozen section biopsy confirmed a borderline Brenner tumor associated with a benign mucinous tumor. Subsequently, total hysterectomy and right salpingo-oophorectomy were performed. The operation was completed without addition procedures LESSONS:: Ovarian torsion is benign in most cases and malignancy is rare. Although very rare, ovarian torsion can occur in postmenopausal women, and it should be taken into consideration that the possibility of malignancy is low in postmenopausal women with normal CA-125 levels. Instead of performing staging surgery, it appears to be appropriate to carry out surgery based on the result of intraoperative frozen section biopsy so that we were able to avoid unnecessary surgical procedures.

Introduction: Epidemiological evidence strongly suggests that steroid hormones are implicated in the pathogenesis of ovarian cancer. Estrogen receptor (ER) and Progesterone receptor (PR) are prognostic indicators for a number of epithelial tumors and may play the same role in ovarian cancers. This study aims to evaluate the expression of ER and PR in epithelial ovarian cancer (EOC) in an African population and compare it with other prognostic factors such as age, International Federation of Gynaecology and Obstetrics (FIGO) stage, grade and histological subtype., Methods: Ninety cases of histologically confirmed EOC were reviewed. Immunohistochemistry was used to assess their ER and PR expression status and was then compared with other demographic variables using statistical methods, with level of significance set at p < 0.05., Results: 30.2% and 8.3% of serous and mucinous carcinomas respectively were ER positive while 41.2% and 22.5% of both tumour types were PR positive. One of the two endometrioid carcinomas showed PR expression but neither were positive for ER. The only case of Brenner tumour in the series was ER positive but negative for PR. There was a significant association between ER and the histological subtypes (p = 0.042) while no significant association was found between PR expression and histological subtypes (p = 0.650). No significant association was found between hormone receptor status, age and stage of the EOC., Conclusion: The study showed a lower ER expression in serous carcinoma compared to large cohorts from developed countries. Future translational studies could be used to determine response of EOC to endocrine therapy.

Vaginal Brenner tumor is extremely rare. Only five cases have been reported in the English literature to date. Here we report a vaginal Brenner tumor in a 76-year old postmenopausal woman, who presented with a 2.5cm-sized sessile vaginal polyp. Microscopically, it showed characteristic features of Brenner tumor consisting of three components; transitional islands, glands, and dense fibrous stroma. The epithelial tumor cells were positive for GATA-3, p63 and ER, but negative for PAX8. The origin of Brenner tumors in the vagina is unclear, but previous reports suggested of Müllerian origin. However, our case revealed that vaginal Walthard nests could be possible precursor lesions based on their immunohistochemical staining results.

Background: Brenner tumors almost always develop in the ovary. Exceptionally, extraovarian Brenner tumors have been reported in the lower abdomen or pelvic organs. Here, we introduce a peculiar case of an extraovarian Brenner tumor arising in the omentum., Case Presentation: A 43-year-old woman presented with a palpable abdominal mass. Computed tomography (CT) scan revealed a 9.0-cm solid mass in the omentum. The tumor was not associated with pelvic structures, including the ovaries. It was excised under the clinical impression of an extragastrointestinal stromal tumor or neurogenic tumor. Grossly, the mass was a well-circumscribed solid tumor, with yellow-tan cut surface and minute cystic spaces. Microscopically, the tumor showed well-defined epithelial nests with variable cystic changes embedded in an abundant fibrous stroma. The cells within the nests were reminiscent of benign urothelial cells in that they had oval, frequently grooved nuclei. The epithelial cells focally showed a gradual transition into the surrounding stromal cells with short spindled features. The urothelium-like cells were positive for pancytokeratin, WT-1, p63, CK7, uroplakin-III, and GATA-3 but were negative for CD34, CD10, CK20, c-KIT, DOG-1, PAX-8, and calretinin. Morphological and immunohistochemical features of the tumor were the same as an ovarian Brenner tumor, and so it was diagnosed as an extraovarian Brenner tumor., Conclusions: Although the location of the tumor was very unusual, we could diagnose the tumor as an extraovarian Brenner tumor on the basis of the histologic and immunohistochemical findings. This is the first case of extraovarian Brenner tumor arising in the omentum near the stomach ever reported in the English literature.

Background: The aim of this study was to investigate cytological features of Brenner tumors according to tumor grade using imprint cytology., Case: Between 2004 and 2015, intraoperative imprint cytology was performed on 8 patients with Brenner tumors suspected to be malignant neoplasmas on gross examination because of their large size and solid part. These consisted of 1 benign, 3 borderline, and 4 malignant tumors. In patients with benign and borderline tumors, naked nucleus-like stromal cells and tumor cells in a sheet-like arrangement were observed against a clear background. The nuclei were round to oval-shaped with finely granular chromatin patterns and small nucleoli. Papillary cell clusters and high nucleus-to-cytoplasm ratios were only observed in 1 borderline case. In cases with malignancy, the background was necrotic. The tumor cells occurred in large papillary clusters. The nuclei showed a high degree of nuclear atypia. Nuclear grooves were present in 6 of our 8 cases and they were scant in the malignant cases., Conclusion: Imprint cytology of Brenner tumors provided no characteristic findings to enable a definitive distinction of benign versus borderline tumors, but it enabled discrimination between malignant and other tumors. Imprint cytology can facilitate intraoperative diagnosis and aid in selecting the appropriate surgical procedure., (© 2017 S. Karger AG, Basel.)

Introduction: Molecular pathological research has contributed to improving the knowledge of different subtypes of ovarian cancer. In parallel with the implementation of the new FIGO staging classification, the WHO classification was revised. The latter is mainly based on the histopathological findings and defines the actual type of tumor. It has, therefore, also an important impact on prognosis and therapy of the patient., Materials and Methods: The new WHO Classification of Ovarian Cancer published 2014 by Robert Kurman and co-authors is summarized. The major changes compared to the hitherto existing classification are presented., Results: The new classification eliminates the previous focus of mesothelial origin of ovarian cancer. Instead, it features a discussion of tubal carcinogenesis of hereditary and some other high-grade serous carcinomas. The previously assumed pathogenesis pathway may be correct for some, but not for all, serous cancers. The new classification was established to classify ovarian cancer in a more consistent way. The earlier transitional cell type of ovarian cancer has been removed while seromucinous tumors have been added as a new entity. The role of some borderline tumors as one possible step in the progression from benign to invasive lesions is incorporated. The article summarizes the essential updates concerning serous, mucinous, seromucinous, endometrioid, clear-cell, and Brenner tumors., Conclusion: The new WHO classification takes into account the recent findings on the origin, pathogenesis, and prognosis of different ovarian cancer subtypes. The tubal origin of hereditary and some non-hereditary high-grade serous cancers is mentioned in contrast to the hitherto theory of mesothelial origin of tumors. Seromucinous tumors represent a new entity.

Malignant epithelial tumors (carcinomas) are the most common ovarian cancers and the most lethal gynecological malignancies. Based on their heterogeneous morphology, a dualistic model of carcinogenesis was proposed in 2004. Type I carcinomas, composed of low grade serous, endometrioid, mucinous, clear cell carcinomas and malignant Brenner tumors, were distinct from type II carcinomas (high grade serous, undifferentiated carcinomas and carcinosarcomas). However, clinical studies failed to demonstrate the prognostic value of such a classification. The main reproach to this dualistic model was that it lumped together in type I tumors, heterogeneous lesions such as clear cell and mucinous carcinomas. Recent advances on molecular genetic alterations and precursor lesions favor the classification of ovarian carcinomas as five distinct diseases. The dualistic model of carcinogenesis in type I and II can finally be applied only to serous ovarian carcinomas (low grade and high grade)., (Copyright © 2016 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

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., (Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Brenner tumours of the ovary are uncommon neoplasms and mostly benign. There is general agreement that Brenner tumors are derived from the surface epithelium of the ovary or the pelvic mesothelium through transitional cell metaplasia. It is essential to categorise these tumours as benign, borderline or malignant type as the biologic behaviour and choice of surgery differs in all of the three categories. The authors report a case of Brenner tumour that had only a single area with a beginning indistinct stroma vessel invasion. However the presence of characteristic epithelial nests, fibromatous stroma, and marked cytological metaplasia without atypia provided important clues to the correct diagnosis--proof of a benign tumour.

Borderline Brenner tumors represent quite a rare entity of ovarian tumors (about 2%) that develop from the surface ovarian epithelium. They are formed from papillary structures made of fibrovascular conjunctive axes covered by a transition epithelium, similar to the urinary bladder epithelium. According to the WHO classification, Brenner tumors present the following forms: benign, borderline and malignant. The benign ones are the most frequent, representing about 95%, the borderline represent about 5%, and the malignant ones less than 1%. We present the case of a 64-year patient who was diagnosed with right ovary cyst. The histopathological examination highlighted the presence of a borderline Brenner tumor at the same time with the cystic lesion, on the same ovary. The surgical treatment led to a complete cure of the patient, so that the yearly ultrasound reexamination did not trace the presence of any tumoral relapse.

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., (Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Computed tomography obtained as part of a urinary tract assessment in a 68-year-old woman incidentally detected a solid adnexal mass. Bilateral salpingo-oophorectomy revealed a unilateral, 4-cm, white to tan-yellow colored, focally calcified, left ovarian mass. Microscopically, the tumor was composed of bland fibroblasts, abundant collagen, and areas of calcification with a minor component composed of nests of epithelial cells with nuclear clefts focally evident, some of which contained central lumens with eosinophilic secretions. The major considerations were fibromatous overgrowth in a Brenner tumor or ovarian fibroma with minor sex cord elements. Immunostains for cytokeratin 7 showed diffuse positivity in the epithelial nests, whereas cytokeratin 20 and inhibin were negative, further supporting the diagnosis of a Brenner 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., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: To assess clinical and pathological features of ovarian transitional cell tumors., Methods: Fourteen cases of ovarian transitional cell carcinoma (TCC) were selected and investigated for their clinical and pathological features. Their immunohistochemical profiles were compared with 12 cases of serous adenocarcinoma (SC) admixed with TCC and 4 cases of EC admixed with TCC 20 cases of pure high-grade serous adenocarcinoma (HG-SC), 15 cases of endometrioid adenocarcinoma (EC), 6 cases of Brenner tumor (BT, 2 cases of malignant BT and 4 cases of benign BT)., Results: The patients' age ranged from 36-63 years (mean, 56 years). All cases underwent surgery and postoperative chemotherapy with TP or CAP program. Clinical follow-up was available in 9 cases, of which 2 patients died. Histologically, all cases showed features of transitional cell carcinoma without BT component. Immunohistochemically, 13 of 14 TCCs were positive for WT-1 and all were positive for CK7, ER, PR and CA125, but negative for Uroplakin III and CK20.Similar immunohistochemical staining patterns were seen in SC admixed with TCC and pure HG-SC. Percentage of the 14 TCC cases were also diffusely positive for BRCA1. All SCs admixed with TCC and pure HG-SCs were diffusely or heterogeneously positive for WT-1, with a sharp contrast and mottled distribution pattern in the heterogeneous cases. All TCCs were diffusely and strongly positive for p53, while 16 of 20 cases of pure HG-SC were positive. The positive ratio of p53 in SCs admixed with TCC cases was 11/12.WT-1 expression in TCCs was significantly higher than BTs, ECs and ECs admixed with TCC (P < 0.01), while no obvious difference was seen when compared with SCs admixed with TCC and pure HG-SCs.SCs admixed with TCC, TCCs and EC were positive for BRCA1 except pure ECs and BTs. The positive rate of Ki-67 of BTs was low, while it was higher in TCCs, SCs admixed with TCC and pure HG-SCs. Only BTs expressed Uroplakin III., Conclusions: Ovarian TCC has characteristic morphological and immunohistochemical features, similar to SC but different from BT. Therefore, TCC should be considered as a morphological variant of HG-SC.

Brenner tumors are composed of urothelial/transitional-type epithelium and, hence, are morphologically similar to Walthard nests and tubal/mesothelial transitional metaplasia. In this study, we analyzed immunohistochemical markers on Brenner tumors to explore Müllerian as well as Wolffian and germ cell derivation. We also attempted to explore their possible association with tubal/paratubal Walthard nests/transitional metaplasia, using the same immunostains. Thirty-two consecutive cases of Brenner tumors were identified. Thirteen (43%) of the patients had Walthard nests in the tubal/periovarian soft tissue. All Brenner tumors were diffusely positive for GATA3 (strongly positive in 30/32 and weakly positive in the remaining 2) and negative for PAX8, PAX2, and SALL4. Similarly, all Walthard nests were positive for GATA3, whereas only 3 (23%) of 13 showed occasional PAX8 expression; all were negative for PAX2 and SALL4. In our study, more than 40% of Brenner tumors had associated Walthard nests. The similar morphology and immunoprofile of Brenner tumors and Walthard nests suggest a probable link between Brenner tumors and Walthard nests. Two additional cases presented highlight small transitional lesions involving the ovary: a possible precursor lesion or the initial steps of Brenner tumor formation. Brenner tumors and most Walthard nests lacked staining for Müllerian (PAX8 and PAX2) and germ cell tumor markers (SALL4)., (Copyright © 2014 Elsevier Inc. All rights reserved.)