Juvenile granulosa cell ovarian tumor (JGCOT) is a rare sex cord stromal tumor, occurring most frequently in premenarchal girls or young women. In contrast to adult granulosa cell tumor, JGCOT has a high mitotic index and more aggressive tumor growth. Microscopically it is seen as diffuse and regularly distributed neoplastic cells with a wide cytoplasm and pleomorphic hyperchromatic nucleus. Follicle formation, in various sizes and shapes, is important in JGCOT. Call-Exner bodies are infrequently seen in JGCOT in contrast to the adult type. [from
HPO]