Ovarian carcinosarcoma of heterologous type occurring in an endometriotic cyst with 3-year recurrence-free survival: a case report and literature review.

A 41-year-old premenopausal woman presented to our hospital with lower abdominal distention and epigastralgia. An ovarian endometriotic cyst was noted when she was 30 years, and was only followed up until she was 36 years. Suspecting rupture of an ovarian tumor, left adnexectomy was performed. The left ovarian tumor was diagnosed as an ovarian carcinosarcoma of the heterologous type occurring in the endometriotic cyst. The carcinosarcoma was composed of an admixture of high-grade carcinomatous and sarcomatous components, including rhabdomyosarcoma. Thereafter, secondary surgery was concluded, which confirmed the tumor stage to be pT1c3. She postoperatively received 6 cycles of docetaxel/carboplatin as adjuvant chemotherapy and achieved recurrence-free survival for 40 months. Among ovarian carcinosarcomas, cases occurring in endometriotic cysts are particularly rare and may have a relatively good prognosis, because tumor cells, especially sarcoma components, tend to be confined to the ovaries. Pathological estimation of the origin of carcinosarcoma is important, because it appears to correlate with prognosis.