Inhibin α and β expression in ovarian stromal tumors and their histological equivalences

Abstract

Inhibin is a heterodimeric protein hormone that appears to be a sensitive immunohistochemical marker of sex cord-stromal tumors. Although sex cord-stromal tumors can usually be distinguished from ovarian epithelial tumors or their metastases by morphology or by using antibodies against intermediate filaments, the diagnosis remains difficult in rare situations in such cases as sarcomatoid granulosa-theca cell tumors, ovarian small cell carcinomas, or soft-tissue sarcomas. The purposes of this study were to examine inhibin alpha and beta immunoreactivity in a wide range of gonadal stromal neoplasms and to assess its value in the differential diagnosis of problematic tumors. A total of 108 paraffin-embedded ovarian and extraovarian tumors were examined immunohistochemically by using anti-alpha inhibin and anti-beta inhibin. Inhibin alpha immunostaining was identified in 46 (81%) of 57 gonadal stromal tumors, one (14%) of seven endometrial stromal tumors, and one (50%) of two primary ovarian carcinoid tumors. Inhibin beta immunostaining was detected in 55 (96%) of 57 gonadal stromal tumors, two (29%) of seven endometrial stromal tumors, one (50%) of two dysgerminomas, and in all of two (100%) primary ovarian carcinoid tumors. Inhibin alpha expression was not detected in any ovarian surface epithelial tumor cells. Some surface epithelial tumors showed stromal inhibin alpha (15% of cases) and inhibin beta (48% of cases) positivity. Weak immunoreactivity for inhibin beta was found in most (83% of cases) ovarian surface epithelial tumors. Two ovarian Burkitt lymphomas were negative for inhibin alpha and beta. Inhibin alpha is a sensitive immunohistochemical marker of gonadal stromal tumors and is of value in the differential diagnosis of ovarian neoplasia. Inhibin beta is a nonspecific marker for ovarian neoplasms, showing expression on tumor and stromal cells of different epithelial or stromal tumors.

Non-Peutz-Jeghers syndrome associated ovarian sex cord tumor with annular tubules: a case report

“…The serum tumor marker inhibin as well as some of immunohistochemical markers (inhibin, MIS, CD99, estrogen receptor, progesterone receptor, and androgen receptor) have been studied as diagnostic tools and predictors of clinical behavior of the tumor postoperatively (15). Non-PJS-associated SCTATs also commonly secrete estrogen and progesterone, although the sensitivity of following serum markers of these hormones is low, especially when residual tumor volume is limited (16). Inhibin, a heterodimeric protein hormone secreted by granulosa cells that acts as an inhibitor of follicle-stimulating hormone (FSH) synthesis, has been known to be a sensitive immunohistochemical marker in diagnosing sex cord stromal tumors.…”

“…In women with non-PJS associated SCTATs, malignant behavior with metastases may be seen in at least 20% of cases (4,(15)(16)(17). Given that this condition is extremely rare, especially in children, our experience in managing a young girl with precocious puberty secondary to a SCTAT may be of value.…”

Cytologic Findings of Low Grade Endometrial Stromal Sarcoma with Sex Cord–like Differentiation

“…2,7 As cells showing sex cord-like alignment in endometrial stromal tumors are negative for inhibin, the sex cord-like elements are not considered to be of true sex cord origin. [8][9][10] Although the cytologic features characteristic of each endometrial tumor have been described, 11-14 differentiation of these 3 forms is not always possible. Scattered spindle cells with high nuclear:cytoplasmic ratio resembling the growth phase of endometrial stroma, with an overall bland appearance and little pleomorphism, have been reported for all 3 forms of endometrial stromal tumors.…”

Comparative Analysis of Alternative and Traditional Immunohistochemical Markers for the Distinction of Ovarian Sertoli Cell Tumor From Endometrioid Tumors and Carcinoid Tumor

“…For example, Sertoli cell tumors can express epithelial markers such as cytokeratin (AE1/AE3 and CK8/18) in 38% to 100% of cases 11,13,21,22,37,49 whereas endometrioid carcinomas can express sex cord markers such as inhibin and calretinin in 0% to 25% and 0% to 36% of cases, respectively. 7,8,10,[14][15][16]19,20,25,[29][30][31][32]35,38,41,47,54 Although sex cord-stromal markers such as inhibin and calretinin have been extensively studied in ovarian sex cord-stromal tumors, most studies are predominantly composed of granulosa cell tumors. The number of Sertoli cell tumors that have been analyzed for various immunohistochemical markers in any given study is very small, and the majority of available immunohistochemical data are based on a mixture of pure Sertoli cell tumors, Sertoli-Leydig cell tumors, and mixed granulosa cell-Sertoli cell tumors (''gynandroblastoma'') from ovarian and testicular sites.…”