A rare, low-grade malignant sex cord-stromal tumor that arises from the testis in adults. It is composed of granulosa cells in an often fibrothecomatous stroma. Several morphologic patterns have been identified and include insular, gyriform, trabecular, pseudosarcomatous, and solid. Gynecomastia is present in approximately a quarter of the patients. Metastases have been reported in a minority of patients. [from
NCI]