OBJECTIVETo study the clinicopathologic features, diagnostic criteria, differential diagnosis and treatment options of ovarian steroid cell tumor, not otherwise specified (NOS).

METHODSLight microscopy and immunohistochemical study was carried out in 8 cases of ovarian steroid cell tumor, NOS. The literature was reviewed.

RESULTSThe 7 cases of benign ovarian steroid cell tumor, NOS were composed mainly of polygonal cells with granular eosinophilic cytoplasm and larger cells with vacuolated cytoplasm. They resembled the architecture of normal adrenal gland, with formation of cell nests and trabeculae. The single case of malignant ovarian steroid cell tumor had evidence of significant cellular pleomorphism, haemorrhage and coagulative tumor necrosis. The mitotic count measured about 7 per 10 high-power fields. Immunohistochemical study showed that the tumor cells expressed calretinin and alpha-inhibin. Differential diagnosis included oxyphilic granulosa cell tumor, thecoma, Sertoli cell tumor and clear cell carcinoma. The treatment options of benign ovarian steroid cell tumor, NOS was local excision or ipsilateral salpingo-oophorectomy, while the malignant counterpart should be treated with a combination of surgery and chemotherapy, including administration of GnRH agonist.

CONCLUSIONSOvarian steroid cell tumor, NOS, is the most common type of ovarian steroid cell tumors. Most of which are associated with a benign clinical outcome. Immunohistochemistry is an important adjunct for diagnosis. The treatment options of ovarian steroid cell tumor, NOS depend on its malignant potential.