ovarian sex cord-stromal tumor (MONDO_0021657, a Monarch Disease Ontology id) is a benign or malignant neoplasm that arises from the ovary and is composed of granulosa cells, Sertoli cells, Leydig cells, theca cells, and fibroblasts. Representative examples include thecoma, fibroma, Sertoli cell tumor, and granulosa cell tumor. Also known as: Sex cord-stromal neoplasm of ovary, Sex cord-stromal neoplasm of the ovary, Sex cord-stromal tumor of ovary, Sex cord-stromal tumor of the ovary, Sex cord-stromal tumour of ovary, Sex cord-stromal tumour of the ovary, ovarian Sex cord-stromal neoplasm, ovarian Sex cord-stromal tumor.