IMMUNOHISTOCHEMICAL STAINING OF OVARIAN GRANULOSA-CELL TUMORS WITH MONOCLONAL-ANTIBODY AGAINST INHIBIN

Inhibin is a peptide hormone produced hy ovarian granulosa cells and b y granulosa cell tumors. Serum inhibin measurements have been used as a biochemical marker of the presence or progression of ovarian granulo sa 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 extraovar ian neoplasms, many of which may mimic granulosa cell tumor. There was diffuse strong cytoplasmic staining of all cases of adult granulosa c ell tumor. Diffuse positive staining also was observed in all Leydig c ell tumors, and there was focal staining in a proportion of fibrotheco mas. There was focal weak staining of one case of ovarian clear cell c arcinoma but no staining of other ovarian and extraovarian neoplasms. Immunohistochemical staining with antibodies against inhibin is of val ue 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. Copyright (C) 199 7 by W.B. Saunders Company.