A low-grade malignant sex cord-stromal tumor that occurs in the ovary and affects middle aged to post-menopausal women. It is composed of granulosa cells in an often fibrothecomatous stroma. The neoplastic cells may form various patterns including the microfollicular, which is characterized by the presence of Call-Exner bodies, macrofollicular, insular, trabecular, and diffuse pattern. Signs and symptoms include abdominal mass, hemoperitoneum, and ascites. Estrogenic and rarely androgenic manifestations may be present. The vast majority of cases present as stage I tumors; however, all tumors have a potential for aggressive clinical course. [from
NCI]