Ovarian thecoma 2017-05-31T00:22:37Z A sex cord-stromal tumor of the ovary. Thecomas range from small tumors to large solid or solid-cystic masses of up to 15 cm. They are unilateral in over 90 percent of cases and are rarely malignant. Thecomas are stromal tumors made up of cells that resemble theca cells, lutein cells and fibroblasts. They are traditionally classified within the sex cord-stromal tumor category of ovarian tumor types. Ovarian sex cord-stromal tumor