Wolffian adnexal tumor, so-called female adnexal tumor of probable Wolffian origin (FATWO): immunohistochemical evidence in support of a Wolffian origin

Value of inhibin staining in gynecological pathology

Recent years have seen the publication of many articles investigating the value of antibodies against inhibin in diagnostic surgical pathology. This review concentrates on the uses of inhibin staining in gynecological pathology. alpha-inhibin is diagnostically the most useful antibody and is a sensitive immunohistochemical marker of most ovarian sex cord-stromal tumors and, as such, is of value in the diagnosis of this heterogeneous group of neoplasms that can be confused morphologically with a wide range of other tumors. Because the antibody is not entirely specific for ovarian sex cord-stromal tumors, it should always be used as part of a larger panel. alpha-inhibin staining may also be of value in confirming late recurrence or metastasis of an ovarian sex cord-stromal tumor, especially a granulosa cell tumor. Sex cord-like elements within uterine tumors resembling ovarian sex cord tumors are also commonly immunoreactive with alpha-inhibin, perhaps indicating true sex cord differentiation. alpha-inhibin staining may also be of value in cytological preparations in confirming a functional cyst and excluding a cyst or cystadenoma of epithelial origin. Syncytiotrophoblastic cells are also immunoreactive, as are most trophoblastic tumors. Thus, positive staining may be of value in confirming an intrauterine gestation or in the diagnosis of a trophoblastic neoplasm. Another gynecological neoplasm that is commonly positive with alpha-inhibin is the so-called female adnexal tumor of probable wolffian origin, and, therefore, the antibody is of no value in the distinction of this neoplasm from a sex cord-stromal tumor, tumors that are often in the differential diagnosis.

Recent advances in immunohistochemistry in the diagnosis of ovarian neoplasms

This leader reviews recent advances in immunohistochemistry that are useful in the diagnosis of ovarian neoplasms. These include the value of different anticytokeratin antibodies in the distinction between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. These antibodies have also helped to clarify the origin of the peritoneal disease in most cases of pseudomyxoma peritonei. The value of antibodies against so called tumour specific antigens, such as CA125 and HAM56, in determining the ovarian origin of an adenocarcinoma is also reviewed. In recent years, several studies have investigated the value of a variety of monoclonal antibodies in the diagnosis of ovarian sex cord stromal tumours and in the distinction between these neoplasms and their histological mimics. These antibodies include those directed against inhibin, CD99, Mullerian inhibiting substance, relaxin like factor, melan A, and calretinin. Of these, anti-alpha inhibin appears to be of most diagnostic value. It is stressed that these antibodies should always be used as part of a larger panel and not in isolation.