theca cell tumor [Gk, theke, sheath; L, cella, storeroom; tumor, swelling] , an uncommon benign fibroid tumor of the ovary, composed of theca cells and usually containing granulosa (follicular) cells. Characteristically solid masses with yellow fatty streaks, these tumors are frequently associated with excessive estrogen production and tend to develop cystic degeneration. Also called fibroma thecocellulare xanthomatodes, thecoma.
