Immunohistochemistry of ovarian granulosa cell tumours. The value of tissue specific proteins and tumour markers

WT1 expression in the female genital tract

The Wilms tumor gene 1 (WT1) has been reported in normal tissues and many neoplasms of the female genital tract. This review discusses WT1 expression in the female genital tract and its potential utility in the differential diagnosis of neoplasms that occur at this location. WT1 is of value in the differential diagnosis of synchronous serous carcinomas arising in the ovary/fallopian tube/peritoneum and endometrium, as strong WT1 positivity in both tumors points toward an extrauterine origin. In addition, WT1 can be used to distinguish sex cord stromal tumors (WT1 positive) from endometrioid carcinomas (OECs). WT1 expression is not helpful in the differential diagnosis of ovarian serous carcinomas (OSCs) and transitional carcinomas, as both are typically positive and has limited value in the distinction of serous tumors arising in the ovary/fallopian tube/peritoneum from mesotheliomas. WT1 is also not helpful to differentiate small cell carcinoma of hypercalcemic type from juvenile granulosa cell tumor, a common diagnostic problem. Intra-abdominal desmoplastic round cell tumor reacts to WT1 (C-terminal) in contrast to all other tumors discussed which helps to separate this rare tumor from most other small round cell tumors that may involve, primarily or secondarily, the ovary with the exception of small cell carcinoma of hypercalcemic type that typically reacts with the N-terminal of WT1.

Mixed germ cell tumor with embryonal carcinoma, choriocarcinoma, and epithelioid trophoblastic tumor in the ovary of a cynomolgus monkey

A seven-year-old female cynomolgus monkey had a mass in the left ovary with metastasis to the lung and the right ovary. The mass of these organs showed three different characteristics, and its immunohistochemical profiles were consistent with embryonal carcinoma (EC), choriocarcinoma (CC), and epithelioid trophoblastic tumor (ETT). The EC was characterized with sheets and glandlike structures with large pleomorphic, single-nucleated epithelial cells that were immunohistochemically positive for α-fetoprotein, octamer-4, and CD30, and with multinucleated giant cells resembling syncytiotrophoblasts. The CC also represented biphasic proliferation of the cytotrophoblast positive for cytokeratin 7 (CK7), which showed negative immunoreactivity for all three of the above antibodies, and it was syncytiotrophoblast positive for human chorionic gonadotropin. The ETT showed numerous floating cells in an abundant eosinophilic extracellular matrix with vacuolated or eosinophilic cytoplasm and was immunohistochemically positive for CK7, p63, and α-inhibin, which features nodule or cordlike structures. Collectively, this neoplasm was identified as a mixed germ cell tumor with EC, CC, and ETT. To our knowledge, this is the first report of EC in nonhuman primates as a component of mixed germ cell tumor.

Inhibin immunohistochemical staining: a practical approach for the surgical pathologist in the diagnoses of ovarian sex cord-stromal tumors

Through a brief introduction of inhibin history, characteristics of the antibody against inhibin, and normal tissue distribution of alpha-inhibin expression, this comprehensive review focuses on a practical approach to using alpha-inhibin in the differential diagnosis of ovarian sex cord-stromal tumors (SCSTs). Alpha-inhibin has become a most useful immunohistochemical marker of gonadal SCST, regardless if the tumors are primary, recurrent, or metastatic. However, pathologic diagnosis of individual SCST is still based largely on morphologic criteria. Alpha-inhibin immunohistochemical (IHC) staining should be used only when a difficult morphologic diagnosis is encountered. In this perspective, alpha-inhibin and other properly selected markers should be ordered at the same time. This is simply because alpha-inhibin is not specific for SCSTs. Caution should be exercised in the interpretation of alpha-inhibin-positive cells, because a wide variety of primary and metastatic ovarian tumors may contain significant numbers of alpha-inhibin-positive stromal cells. As with other immunohistochemical stains, a panel of stains and comparison with the corresponding hematoxylin and eosin (H&E) slides is necessary, especially when staining patterns and cellular localization are in question. The antibody will not help to differentiate tumors within the category of SCST. The pattern or the intensity of staining in SCSTs does not predict tumor behavior, although there is a tendency of loss of alpha-inhibin expression in poorly differentiated Sertoli or Sertoli-Leydig cell tumors. In cases where metastatic granulosa or Sertoli-Leydig cell tumors are a concern, positive alpha-inhibin staining is diagnostic, but a negative result does not rule out metastatic disease. Calretinin has been recently recognized as a more sensitive, but less specific marker for SCSTs and it may be used to recognize an inhibin-negative SCST. In this review, we have listed nine of the most commonly encountered clinical scenarios where alpha-inhibin and other markers could be used in diagnostic surgical pathology of ovarian tumors.

Immunohistochemical study of testicular sex cord-stromal tumors, including staining with anti-inhibin antibody

Inhibin is a peptide hormone produced by ovarian granulosa cells and testicular Sertoli cells. Ovarian granulosa cell and other sex cord-stromal tumors usually exhibit positive immunohistochemical staining with antiinhibin antibodies, and this may be valuable in differentiating these neoplasms from histologic mimics. In the present study, we investigated the immunohistochemical staining of testicular sex cord-stromal tumors using antiinhibin. Immunostaining with CAM5.2, vimentin, S-100 protein, desmin, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and placental alkaline phosphatase (PLAP) also was performed because few studies have investigated in detail the immunophenotype of testicular sex cord-stromal tumors. Fifteen of 16 Leydig cell tumors exhibited strong positive staining with antiinhibin. A proportion of Leydig cell tumors also stained positively with CAM5.2 (7 of 16), vimentin (14 of 16), S-100 protein (10 of 16), desmin (2 of 16) and epithelial membrane antigen (4 of 16). Four of six testicular sex cord-stromal tumors with varying degrees of Sertoli or granulosa cell differentiation were positive with antiinhibin, as were two of three sex cord-stromal tumors that were unclassified. Some of these tumors were positive with CAM 5.2, vimentin, S-100 protein, desmin, and epithelial membrane antigen. All tumors were negative with carcinoembryonic antigen and placental alkaline phosphatase. The immunohistochemical findings show that, analogous to their ovarian counterparts, most testicular sex cord-stromal tumors are immunoreactive with antiinhibin. Immunohistochemistry using this antibody as part of a panel may be valuable in confirming a diagnosis of testicular sex cord-stromal tumor and in differentiating these neoplasms from others that may mimic them.

Value of inhibin in the identification of granulosa cell tumors of the ovary

Inhibins are peptide hormones that participate in the regulation of the pituitary-gonadal feedback system and are selectively expressed by cells of sex cord-stromal derivation. To determine the efficacy of this marker for distinguishing granulosa cell tumors, 134 primary and metastatic lesions of the ovary were evaluated for expression of the alpha-subunit of inhibin in routinely processed formalin-fixed, paraffin-embedded tissue. A variety of sex cord-stromal tumors (SCST), including 35 adult and juvenile granulosa cell tumors, 14 fibroma-thecomas, and 18 other sex cord-stromal proliferations, were studied. In addition, 33 surface epithelial neoplasms, 12 germ cell tumors, 11 metastases, and 11 miscellaneous ovarian neoplastic proliferations were evaluated. Among the non-granulosa cell neoplasms, special emphasis was placed on primary neoplasms and metastases that histologically simulated granulosa cell tumors. Thirty-three of 35 (94%) granulosa cell tumors were immunoreactive compared with 2 of 12 (17%) primary ovarian endometrioid tumors, one of nine (11%) primary ovarian transitional cell (Brenner) proliferations, and 3 of 17 (18%) other primary and metastatic poorly differentiated (undifferentiated) carcinomas. In 31 of the 35 granulosa cell tumors, inhibin staining was of moderate to strong intensity or was present in at least half of the constituent cells, whereas only 2 of 33 primary surface epithelial neoplasms fulfilled the same criteria, showing weak staining of 70% to 80% of the cells. In contrast, 10 of 14 (71%) ovarian fibroma-thecomas and 17 of 18 (94%) other sex cord-stromal proliferations were positive for inhibin. Nonneoplastic luteinized stromal cells stained for inhibin in 29 of 85 cases in which they could be evaluated. The results of this study show that although it is not completely specific and cannot reliably distinguish granulosa cell tumors from fibroma-thecomas or other ovarian sex cord-stromal proliferations, inhibin can be used to help distinguish sex cord-stromal neoplasms from most primary and metastatic non-SCST. Caution should be exercised in the interpretation of inhibin-positive cells, because a wide variety of primary and metastatic ovarian tumors may contain significant numbers of positively staining luteinized cells.

Inhibin immunohistochemistry applied to ovarian neoplasms: a novel, effective, diagnostic tool

Immunohistochemistry using monoclonal antibodies against human inhibin, a peptide hormone produced by ovarian granulosa cells to inhibit follicle-stimulating hormone (FSH), has been recently applied to diagnostic anatomic pathology. This investigation hypothesizes that inhibin immunohistochemistry will aid in the crucial clinical distinction between sex cord-stromal and other primary ovarian neoplasms. Available H&E slides and clinical information from a retrospective surgical series of 186 primary ovarian tumors were reviewed to verify diagnoses, and representative paraffin sections were immunostained with anti-inhibin (R1 monoclonal, Serotec, Kidlington, Oxford, UK). Immunoreactivity was graded as weak/strong (W/S), and the proportion of strong staining cells was coded as follows: S1 = <10%, S2 = 10%-50%, S3 = >50%, respectively. Inhibin immunoreactivity for 137 sex cord-stromal lesions was as follows: 100% of 66 granulosa cell tumors: 80% S3, 20% S2; 100% of 17 Sertoli-stromal tumors: 90% S3, 10% S2; 100% of 13 hyperplastic follicular/stromal lesions: 90% S3, 10% S2; 100% of six steroid cell tumors: 100% S3; 90% of 18 thecomas: 40% S3, 10% S2, 10% S1, 30% W; 0% of 12 fibromas, three myxomas, and two sclerosing stromal tumors. None (0 of 49) of the other ovarian neoplasms exhibited inhibin: 22 carcinomas, 12 carcinosarcomas, seven small cell carcinomas, six germ cell tumors, and two lymphomas. In the typical case, the distinction between sex cord-stromal and other ovarian neoplasms requires nothing more than routine pathological examination. In diagnostically challenging cases, our data indicate that inhibin immunohistochemistry is a very useful adjunct because granulosa and sertoli-stromal tumors are positive whereas other potential mimickers have been negative thus far.

Immunohistochemical staining of ovarian granulosa cell tumors with monoclonal antibody against inhibin

Inhibin is a peptide hormone produced by ovarian granulosa cells and by granulosa cell tumors. Serum inhibin measurements have been used as a biochemical marker of the presence or progression of ovarian granulosa cell tumors and their metastases. In the current study, an antibody against the alpha-subunit of human inhibin was used to stain 16 cases of ovarian adult granulosa cell tumors, 15 cases of other ovarian sex cord-stromal tumors, and 51 cases of a range of ovarian and extraovarian neoplasms, many of which may mimic granulosa cell tumor. There was diffuse strong cytoplasmic staining of all cases of adult granulosa cell tumor. Diffuse positive staining also was observed in all Leydig cell tumors, and there was focal staining in a proportion of fibrothecomas. There was focal weak staining of one case of ovarian clear cell carcinoma but no staining of other ovarian and extraovarian neoplasms. Immunohistochemical staining with antibodies against inhibin is of value in the diagnosis of granulosa cell tumor and in the distinction of this neoplasm from others that may mimic it. The antibody also may be useful for the confirmation of late metastasis of granulosa cell tumor, especially when the previous history is not known.

Computed tomography, diagnosis, staging and follow-up of pure granulosa cell tumour of the ovary

Granulosa theca cell tumours represent the largest group of hormone-secreting ovarian tumours and comprise approximately 1.5% of all ovarian malignancy. However, the prognosis and behaviour of pure granulosa cell tumours have been particularly difficult to evaluate, because in previous reports they have been grouped with granulosa theca cell tumours. Consequently, their radiological features and the possible contribution of computed tomography (CT) to clinical management has not been evaluated. We report the CT appearances of 15 patients with pure granulosa cell tumours and their clinical outcome. The results suggest the possibility of a positive relationship between histological grade and FIGO stage at presentation. Large tumour volume, extensive lymph node involvement and ascites on CT are adverse prognostic features. However, patients with abdominal masses less than 9 cm in diameter, absent or small volume lymph node disease and peritoneal and liver metastases achieved complete remission, suggesting that CT can assist in identifying those patients likely to respond best to current therapeutic regimens.

Immunohistochemical phenotype of ovarian granulosa cell tumors: absence of epithelial membrane antigen has diagnostic value

Granulosa cell tumors (GCTs) represent 1.5% to 3% of primary and 6% to 10% of malignant ovarian neoplasms, and present little diagnostic difficulty in the typical case; however, other primary or metastatic tumors may mimic their various histologic patterns. For this reason, immunohistochemistry can be used to supplement routine histology to help determine a final tissue diagnosis. Previous reports on the utility of antibodies to intermediate filaments vary, as some investigators found keratin to be uniformly negative in GCTs while others reported immunoreactivity for keratin in 20% to 68% of cases. To determine the immunophenotype of granulosa cell tumors and to discover which antibodies are useful in differentiating GCTs from histologic look-alikes, we studied 52 GCTs, including 24 typical cases, 23 cases in which the diffuse pattern predominated, and five juvenile cases, with a panel of commercially available antibodies using an automated immunohistochemistry system. Immunoreactivity for granulosa cells in GCTs was as follows: 17 cases (32.7%) reacted with cytokeratin AE1/AE3, six cases (11.5%) reacted with cytokeratin MAK-6, three cases (5.8%) reacted with cytokeratin CAM 5.2, no case (0%) reacted with epithelial membrane antigen, 52 cases (100%) reacted with vimentin, no case (0%) reacted with desmin, 48 cases (92.3%) reacted with smooth muscle actin, and 26 cases (50%) reacted with S-100 protein. No attempt was made to quantify staining of background thecoma-like or fibroma-like elements in GCTs. Immunoreactivity was independent of the histologic subtype of GCT. Cytokeratin immunoreactivity showed a globoid pattern of staining and was consistent with the expression of 52.5-kD and 45-kD cytokeratins (8 and 18 of Moll's classification). For this reason, the presence of cytokeratin immunoreactivity by itself cannot be used to differentiate a primary or metastatic carcinoma from a GCT. The presence of smooth muscle actin and the absence of epithelial membrane antigen immunoreactivity are additional features that are characteristic of a GCT. S-100 protein immunoreactivity is a finding limited exclusively to GCTs among sex cord stromal tumors, and its presence may have some role in differentiating between Sertoli-stromal cell tumors and GCTs. Since epithelial membrane antigen immunoreactivity is present in many of the histologic look-alikes of GCTs, such as metastatic or primary carcinoma, the absence of staining in GCT has diagnostic value.

Granulosa cell tumor of the adult testis: a clinicopathologic study of seven cases and a review of the literature

We report a study of seven men, aged 16 to 76 years (average age, 47.4 years) with granulosa cell tumor (GCT) of the testis. Three patients presented with testicular enlargement of several years' duration and a fourth presented with a testicular enlargement of unknown duration. The tumors in three patients were detected during routine physical examination. None of the patients had endocrine-related symptoms. All tumors were well circumscribed and showed the solid, cystic, microfollicular, gyriform, insular, and trabecular patterns typical of GCT of the ovary. Call-Exner bodies were present in three tumors and two tumors had a focal spindle-cell component. In one case the surrounding testicular parenchyma showed Leydig's cell hyperplasia and a Sertoli cell nodule. The tumor cells revealed strong immunoreactivity for vimentin but showed no expression for keratin or epithelial membrane antigen. One patient developed liver and retroperitoneal lymph node metastases 121 months after initial diagnosis and died 13 months later. Another patient initially presented with retroperitoneal lymph node metastasis and developed metastasis to the inguinal lymph nodes 12 months later. Three patients are alive at 1, 4, and 37 months with no evidence of disease. Another patient died of an unrelated condition. Follow-up information was not available for the seventh patient. Twelve cases of GCT of the adult testis have been reported in the literature, with metastases occurring in two: one of these two patients had a tumor for 8 years and died of disease 5 months after diagnosis with multiple metastases and the other had metastasis at the time of diagnosis, but was free of disease for 14 years. Our findings and a review of the literature indicate that GCT of the adult testis is a rare and slow-growing neoplasm with the potential to form distant metastases. Because recurrence or distant metastasis may occur late in the clinical course, long-term follow-up of these patients is recommended.

Demonstration of cytokeratin intermediate filaments in oocytes of the developing and adult human ovary

The intermediate filaments (IF) present in the various cells of human ovaries were studied by immunolocalization using antibodies to cytokeratins (CKs), vimentin, desmin and alpha-smooth muscle (alpha-SM) actin. Oocytes revealed a single paranuclear aggregate, which reacted with antibodies to CKs 8, 18 and 19 both in adult and fetal ovaries. The existence of this aggregate was also documented by electron microscopy. Ovarian surface epithelium and granulosa cells consistently coexpressed CKs 8, 18, 19 and vimentin. During follicle maturation vimentin remained unchanged in the granulosa layer while CKs content decreased, showing variation in the amount and distribution of the different CK-types. Thecal cells of secondary and mature follicles showed alpha-SM actin positivity. These contractile fibres increased in mature follicles. Ordinary fibrous stromal cells showed isolated cells which were desmin and alpha-SM actin positive. A similar pattern of IF expression and distribution existed in all stages of development in fetal and embryonic ovaries. These results indicate that CKs are present in human oocytes and that the coexpression of vimentin and CKs can be regarded as a peculiar feature of all ovarian cell types except oocytes and ordinary stromal cells. Contractile properties have been documented associated with a modification in expression of IF proteins. This is likely to represent an integral part of folliculogenesis along with the functional hormone-dependent changes.

Expression of cytokeratins in granulosa cell tumors and ovarian carcinomas

One of the problems in histopathology of ovarian tumors is differential diagnosis between the poorly differentiated carcinomas and granulosa cell tumors of the sarcomatoid type. Hence we evaluated the expression of various cytokeratins (CK 1-19; CK 10, 13, 14, 15, 19; CK 8, 18, 19; CK HMW 1, 5, 10, 11; CK 8; CK 1-19 Stähli; CK AE1/AE3) immunohistochemically in 53 ovarian malignancies (11 of them poorly differentiated carcinomas and 12 granulosa cell tumors). CK HMW was not detected in granulosa cell tumors, and in only half of the carcinomas. AE1/AE3 was expressed by more than 90% of ovarian carcinomas but by one granulosa cell tumor only. The other keratins we investigated showed higher expression rates in granulosa cell tumors and/or lower expression rates in ovarian carcinomas. We think that cytokeratin immunohistochemistry is of value in differentiating between granulosa cell tumors and ovarian carcinomas.

Cell-to-cell communication competence in simian virus 40-transfected rat ovarian cells is reduced following tumor selection

A pSV3neo-transfected rat ovarian cell line (SV-GC) was developed from a primary granulosa culture (GC) to study gap junctional intercellular communication (GJIC) during Simian virus 40 (SV40) transformation. SV-GC expressed SV40 large T-antigen (T-ag), grew indefinitely in culture without luteinization, was anchorage independent, and formed tumors in nude mice. Ultrastructural analysis identified abundant gap junctional membrane and suggested that SV-GC was arrested at an early stage of differentiation. Functional GJIC, measured by a dye transfer technique (gap FRAP), was comparable to that observed in normal granulosa cells, suggesting that the expression of T-ag alone was insufficient to reduce GJIC. However, there was approximately a 50% loss in the rate of GJIC in the nude mouse SV-GC-tumor derived and G418 selected cell line (T-SV-GC). SV-GC----T-SV-GC also resulted in a transition from migration of cells as an epithelial sheet to the dissociation of individual fibroblastoid cells. Tumor cell detachment was also seen in migrating malignant human (A2780 and 547) and rat (DC3) ovarian cell lines. Co-culture combinations of normal (GC)----transformed (SV-GC)----tumor-derived (T-SV-GC) cells indicated that the rate of heterologous GJIC was characteristic of the least communicating partner. Taken together, these data suggested that SV-GC----T-SV-GC represented progression toward metastasis with concomitant reduction of GJIC and adhesiveness. These sequentially derived cell lines may be a useful in vitro model system for studies focusing on the mechanism involved in the detachment of cells during the progression of ovarian cancer.

Immunohistochemical differentiation between ovarian granulosa cell tumors and ovarian carcinomas

Differential diagnosis is a major problem in histopathology of ovarian tumors. Difficulties may arise if the tumor is a poorly differentiated carcinoma or a granulosa cell tumor of the sarcomatoid type. It was the aim of the present study to evaluate the usefulness of immunohistochemistry in differentiating between granulosa cell tumors of the ovary and ovarian carcinomas. We investigated 56 ovarian malignancies (13 granulosa cell tumors, 17 serous, 14 mucinous and 12 poorly differentiated carcinomas) and performed immunohistochemical detection of Vimentin, Keratin, CA125, CA19-9, CEA, S100 and Ber-EP4. Expression of Vimentin was highest and expression of Keratin was lowest in granulosa cell tumors in contrast to carcinomas. CA125 and CA19-9 were not expressed in granulosa cell tumors, whereas the detection rate in carcinomas (except for CA125 in mucinous carcinomas) was high. CEA, S100 and Ber-EP4 do not seem to be useful markers in differential diagnosis. A marker profile of Vimentin, Keratin, CA125 and CA19-9 allows a quite strict differentiation between poorly differentiated ovarian carcinomas and granulosa cell tumors of the ovary.