An invasive cystic adenocarcinoma arising from the ovary. It is characterized by the presence of malignant glandular epithelial cells which contain intracytoplasmic mucin. The malignant cells invade the ovarian stroma and the cystic spaces contain mucoid material. In a minority of cases both ovaries are involved by the tumor. The prognosis for stage I tumors is excellent. Patients with metastases usually have a poor prognosis. The disease is Monarch Disease Ontology term MONDO_0002701 (ovarian mucinous cystadenocarcinoma). Also known as: mucinous cystadenocarcinoma of ovary, mucinous cystadenocarcinoma of the ovary, ovary mucinous cystadenocarcinoma.