Immunohistochemistry as an adjunct for challenging histological patterns of borderline Brenner tumors: An illustrative study of 4 cases.

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.

Brenner Tumor of the Ovary: A 10-Year Single Institution Experience and Comprehensive Review of the Literature.

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.

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.

FOXA1 is expressed in ovarian mucinous neoplasms.

FOXA1 is a transcription factor essential for the binding and action of other transcription factors on the chromatin. It is the major regulator of endoderm differentiation. It has important roles in breast, prostate and endometrial cancer. It has never been studied in ovarian tumours. The aim of this study was to investigate its expression in ovarian epithelial neoplasms. A total of 195 primary ovarian epithelial borderline or malignant tumours were immunohistochemically studied for the expression of FOXA1. Nineteen percent of the tumours strongly and diffusely expressed FOXA1. Of these, 75.7% belong to the mucinous category (p < 0.0001). Seventy-five per cent of mucinous borderline tumours and 46.7% of mucinous carcinomas overexpressed FOXA1. Brenner tumours also expressed FOXA1. FOXA1 was rarely expressed in serous (6/115) and endometrioid tumours (1/11). Clear cell tumours were completely negative (0/16). Of normal structures, ciliated tubal cells, Walthard nests and transitional metaplasias of the tubal-mesothelial junction, all strongly expressed FOXA1. In conclusion, FOXA1 is found in ovarian mucinous and Brenner tumours.

Testosterone Aromatization to Estradiol in Course of Ovarian Functioning Brenner Tumor Associated With Endometrial Carcinoma and Endometriosis (Roncati-Manenti Triad).

OBJECTIVE: Aromatization is the biochemical process in which aromatase catalyzes the conversion of testosterone into estradiol, the fundamental pathway for the synthesis of estrogens. When enhanced, it can lead to hyperestrogenism, a well-known risk factor for gynecological cancers. METHODS: The surgical specimens, coming from 2 postmenopausal women with hyperestrogenism on pap smear and bioptic diagnosis of endometrial endometrioid carcinoma, were fixed in 10% neutral buffered formalin, paraffin embedded, and then submitted for routine hematoxylin/eosin staining and immunohistochemical characterization for antiestrogen, antiprogesterone, antitesterone, anti-MLH1, anti-PMS2, anti-MSH2, and anti-MSH6. RESULTS: The presence of an undescribed triad represented by ovarian functioning Brenner tumor, endometrial carcinoma, and pelvic endometriosis has been ascertained. The immunohistochemical investigation proved a normal expression of the DNA mismatch repair proteins and revealed a bimodal hormonal status in the pathological tissues, that is, the Brenner tumor cells showed a high expression of testosterone, contrariwise endometrioid carcinoma and endometriosis a high estrogen and progesterone immunolabeling. CONCLUSIONS: This synchronous triad underlines the importance of aromatization and hyperestrogenism in the development of gynecological malignancies in which the immunohistochemical detection of an active source of hormone production - to always keep in consideration during synchronous diseases - can guide subsequent antihormone chemotherapy based on aromatase inhibitors.

Stromal Overgrowth in a Brenner Tumor or Ovarian Fibroma With Minor Sex Cord Elements?

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.

[Clinicopathologic features observation of ovarian transitional cell tumors].

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.

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.

Borderline Brenner tumor of the ovary: a case report with immunohistochemical and molecular study.

BACKGROUND: Borderline Brenner tumor of the ovary is a rare entity characterized by papillary structures with a fibro-vascular core, covered by a transitional epithelium, and by the absence of stromal infiltration. It is associated, by definition, with a benign component of Brenner tumor. CASE: We report a case of a 68-year-old woman, with a right ovarian mass, whose morphology and immuno-profile were consistent with the diagnosis of a borderline Brenner tumor. Immunohistochemistry carried out on selected markers may help to formulate the diagnosis, more than the molecular analyses.

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

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).

An unusual case of a borderline Brenner tumor associated with bilateral serous cystadenoma and endometrial carcinoma.

Brenner tumor accounts for 1.5 to 2.5% of ovarian tumors. Nearly all are benign and 1% malignant. Less than twenty-five cases of borderline Brenner tumor have been reported worldwide. Our case is the first one related to a bilateral ovarian serous cystadenofibroma and endometrioid adenocarcinoma. This unusual case increases the limited data for borderline Brenner tumors.

The pathogenesis of atypical proliferative Brenner tumor: an immunohistochemical and molecular genetic analysis.

Brenner tumors are ovarian tumors, usually benign, containing epithelium that resembles transitional epithelium. As with other epithelial tumors there exist frankly malignant tumors and tumors that display greater proliferation than the benign Brenner tumors but lack destructive infiltrative growth, and these have been designated 'atypical proliferative' (borderline) Brenner tumors. There have been no well-documented cases of atypical proliferative Brenner tumors that have exhibited malignant behavior. Based on shared morphologic features it is generally believed that atypical proliferative Brenner tumors develop from benign Brenner tumors. The aim of the present study was to confirm this impression by investigating the immunohistochemical and molecular genetic features of benign and atypical proliferative Brenner tumors. Immunohistochemical staining for p16, fluorescence in-situ hybridization (FISH) for CDKN2A (p16-encoding gene) and mutational analysis of the genes commonly mutated in ovarian tumors were performed. p16 immunostaining was positive in the epithelial component of 12 (92%) of 13 benign Brenner tumors, but completely negative in all 7 atypical proliferative Brenner tumors. FISH identified homozygous deletion of CDKN2A in the epithelial component of all atypical proliferative Brenner tumors, but CDKN2A was retained in all benign Brenner tumors. Two PIK3CA somatic mutations were detected in the stromal component in 1 (5%) of 20 Brenner tumors and 3 somatic mutations (1 in KRAS and 2 in PIK3CA) were identified in the atypical epithelial component of 2 (29%) of 7 atypical proliferative Brenner tumors. In summary, our findings suggest that loss of CDKN2A and, to a lesser extent, KRAS and PIK3CA somatic mutations have a role in the progression of a benign to an atypical proliferative Brenner tumor.

Ovarian tumors with functioning stroma: a clinicopathologic study with special reference to serum estrogen level, stromal morphology, and aromatase expression.

Ovarian tumors with functioning stroma often show estrogenic manifestations. The range of serum estrogen level, however, has not been analyzed, nor the correlation with the stromal morphology. We reviewed the preoperative serum level of estradiol (E2) in 20 postmenopausal ovarian tumors that contained lutein- or theca-like cells in the stroma. Tumor histology included mucinous (n=7), endometrioid (n=4), clear (n=4), or Brenner tumor (n=2), carcinosarcoma (n=2), and Krukenberg tumor (n=1). Overall, the preoperative serum level of E2 ranged widely from 12.1 to 162.4 pg/mL (reference range, 10-30 pg/mL). The range of serum E2 was 24.9 to 162.4 pg/mL (mean, 58.0 pg/mL) in 7 tumors containing lutein-like cells, and 12.1 to 157.8 pg/mL (mean, 57.0 pg/mL) in 13 tumors containing theca-like cells alone. There was no significant difference in the serum E2 level between the 2 groups. To determine whether the functioning stroma is capable of final conversion of androgens to estrogens, the expression of P450 aromatase was examined immunohistochemically. P450 aromatase was exclusively expressed in the stromal cells, both lutein- and theca-like cells, in 16 tumors. In all tumors, however, it was focally or sparsely distributed, and there was no correlation between the immunoreactivity for P450 aromatase and the serum E2 level. These findings indicate that the functioning stroma, regardless of cell morphology, has a capacity for converting androgens to estrogens, but a significant amount of serum estrogens is finally qualified in the aromatase-rich peripheral tissues.

Ovarian Brenner tumour: a morphologic and immunohistochemical analysis suggesting an origin from fallopian tube epithelium.

BACKGROUND: Brenner tumours (BTs), like other epithelial ovarian tumours, are thought to develop from the ovarian surface epithelium. AIM AND METHODS: We hypothesised that BTs arise from transitional metaplasia near the tuboperitoneal junction which, when embedded in the ovary as Walthard cell nests, may progress to BTs. The aim of this study was to validate this hypothesis by a morphologic and immunohistochemical (IHC) analysis. RESULTS: The IHC analysis revealed that fallopian tube secretory cells, transitional metaplasia, Walthard cell nests and the epithelial component of BTs shared a similar IHC profile, consistently expressing AKR1C3 (an enzyme involved in androgen biosynthesis) and androgen receptor, but not calretinin. The tumour stromal cells that immediately surrounded the epithelial nests showed strong expression of calretinin, inhibin and steroidogenic factor 1 (markers of steroidogenic cells) in the majority of BTs. Using a highly sensitive immunofluorescent staining method, we detected small groups of cilia in transitional metaplasia and Walthard cell nests, multifocal stretches of cilia and/or ciliated vacuoles in benign BTs and well-developed cilia in atypical proliferative BTs. CONCLUSIONS: Our findings suggest a tubal origin of BTs through transitional metaplasia and Walthard cell nests, based on their anatomic proximity, similar IHC profile and the presence of cilia. In addition, we hypothesise a role of androgenic stimulation in the pathogenesis of BT, based on the IHC staining pattern of calretinin, inhibin and steroidogenic factor 1 expressed in the luteinised stromal cells surrounding the epithelial nests of the tumours, and AKR1C3 and androgen receptor expressed in both the epithelial and stromal components.

Ovarian transitional cell carcinoma represents a poorly differentiated form of high-grade serous or endometrioid adenocarcinoma.

Ovarian transitional cell tumors include Brenner tumors (BTs) and transitional cell carcinoma (TCC; non-BTs) according to the most recent World Health Organization classification. However, it remains a matter of debate whether TCC represents a distinct entity or a morphologic variant of high-grade serous adenocarcinoma (HG-SC). The purpose of this study was to resolve the above question by clarifying the morphologic, immunohistochemical, and molecular features of TCC. We reviewed 488 cases of epithelial ovarian carcinomas and reclassified them on the basis of the most recent World Health Organization classification with the modifications proposed by Köbel and colleagues, and 35 cases of TCC were identified; 25 and 6 TCCs were admixed with HG-SC and endometrioid adenocarcinoma (EC), respectively, and the remaining 4 cases were pure TCC. TCC components were not observed in any clear cell carcinomas or mucinous adenocarcinomas. Only 2 cases of malignant BT were identified. In addition to TCCs, malignant BTs, and related adenocarcinomas, benign and borderline BTs were included in the following immunohistochemical and molecular analyses. Immunohistochemically, pure TCCs, TCCs admixed with HG-SC, and pure HG-SCs were characterized by frequent aberrant p53 expression (diffuse or null pattern) and WT1+/ER+/PR+/IMP2+ immunophenotype, whereas BTs, including benign, borderline, and malignant BTs, were characterized by lack of aberrant p53 expression and WT1-/ER-/PR-/IMP2- immunophenotype. In contrast to the BTs, pure ECs and TCCs admixed with EC showed an ER+/PR+ immunophenotype. Nearly all the tumors with a TP53 gene mutation by molecular analysis showed aberrant p53 staining patterns. In conclusion, TCC is not a distinct entity but a poorly differentiated form of serous or EC, as (1) most TCCs coexist with HG-SC (mostly) or EC (occasionally), and (2) the immunophenotype and molecular features are similar to those of HG-SC or EC but different from those of BTs.

Transitional cell tumors of the ovary: a compact group with a heterogeneous histological and immunophenotypical pattern.

A small percentage of ovarian neoplasms are transitional cell tumors, which proves to be a distinct group with various histological and immunohistochemical patterns. In this study, 13 archived formalin-fixed paraffin-embedded samples of transitional cell tumors of the ovary have been assessed using standard HE stain and the indirect tristadial ABC peroxidase IHC method for 11 antibodies (CA125, CK7, CEA, EMA, MNF116, CK20, Vim, ER, PgR, PCNA, Ki-67). More than 50% were malignant Brenner tumors. CA125 was positive in all malignant tumors (of Brenner type and transitional cell carcinomas), but not in benign and borderline tumors, while CK7 was positive in approximately 70% of all cases. These two antibodies have shown a high sensitivity and low specificity, but do not correlate to each other. PCNA was positive in the study batch with a mean value of 40% and Ki-67 with a mean value under 25%. A direct correlation statistically significant has been noted between the aforementioned proliferation factors and the tumor grade (r = 0.4, p = 0.05). The other markers were unspecific, with low sensitivity and independently of the histopathological type.

p63 expression in ovarian tumours: a marker for Brenner tumours but not transitional cell carcinomas.

AIMS: To investigate p63 expression in ovarian neoplasms. METHODS AND RESULTS: Immunohistochemistry using an antibody that detects all p63 isoforms was performed on 103 primary ovarian neoplasms of different histological types. Diffuse nuclear immunoreactivity of p63 was demonstrated in the 17 benign and five borderline Brenner tumours. Only one of the six malignant Brenner tumours displayed p63 expression. p63 immunoreactivity was absent in all the ovarian transitional cell carcinomas (TCC), but was demonstrated extensively in TCCs of the urinary bladder. Besides focal p63 expression in epidermal basal cells of immature and mature teratomas, all other ovarian lesions were devoid of p63 expression. p63 expression was also demonstrated in cervical transitional cell metaplasia and Walthard cell nests of fallopian tubes. CONCLUSIONS: Expression of p63 protein is apparently cell lineage specific and in ovarian neoplasms is confined to benign and borderline Brenner tumours. The loss of expression in malignant Benner tumours suggests a role for p63 in Brenner carcinogenesis. The distinct patterns of p63 expression in TCCs in the ovary and urinary bladder may help in their differential diagnosis.