Ovarian mucinous cystadenoma with a mural nodule of osteosarcoma: A case report

Objective: Osteosarcoma as a mural nodule in the ovary is extremely rare. We aimed to describe a case of a mural nodule with features of an osteosarcoma arising in an ovarian mucinous cystadenoma. Case report: The 65-year-old woman presented with progressive abdominal swelling and poor intake. Image studies showed a huge (diameter, >30 cm) intra-abdominal multiloculated cystic lesion, suspected to be an ovarian tumor. She underwent unilateral salpingo-oophorectomy with no postoperative adjuvant therapy. She was disease-free at 16-month follow-up. Conclusion: Osteosarcoma presenting as a primary ovarian neoplasm is rare, either as a pure osteosarcoma or arising from a teratoma. However, two osteosarcoma cases occurring arising from a mural nodule in an ovarian mucinous neoplasm have been reported. There is no consensus regarding the treatment strategy for osteosarcomatous mural nodules in mucinous tumors because of its rarity. More case studies are needed before its pathogenesis can be fully understood.