A mature or immature teratoma that arises from the ovary and occurs in children. The disease is childhood teratoma of the ovary (MONDO_0003819). Also known as: childhood ovarian teratoma, childhood teratoma of ovary, ovarian teratoma of childhood, paediatric ovarian teratoma, paediatric teratoma of ovary, paediatric teratoma of the ovary, pediatric ovarian teratoma, pediatric teratoma of ovary.