The term hyperthecosis refers to the presence of nests of luteinized theca cells in the ovarian stroma due to differentiation of the ovarian interstitial cells into steroidogenically active luteinized stromal cells. These nests or islands of luteinized theca cells are scattered throughout the stroma of the ovary, rather than being confined to areas around cystic follicles as in the polycystic ovary syndrome (PCOS). The result is greater production of androgens.
The clinical features of hyperthecosis are similar to those of PCOS. However, women with hyperthecosis often have more markedly elevated testosterone, more hirsutism, and are much more likely to be virilized.