ovarian cystadenoma (MONDO_0005183) is a benign ovarian surface epithelial-stromal tumor characterized by the presence of cystic structures lined by serous epithelial cells, mucinous columnar epithelial cells, or endometrial-type well-differentiated cells. Also known as: benign cystadenoma of ovary, benign cystadenoma of the ovary, benign ovarian cystadenoma, cystadenoma of ovary, cystadenoma of the ovary, cystoma serosum simplex, ovary cystadenoma, simple cystoma of ovary.