A category of rare neoplasms that arise from the ovary. It includes low grade endometrioid stromal sarcoma and undifferentiated sarcoma. The disease is ovarian endometrioid stromal and related neoplasms (Monarch Disease Ontology identifier MONDO_0003312). Also known as: endometrioid stromal and related neoplasms of ovary, ovary endometrioid stromal and related neoplasms.