Carcinosarcoma arising from uterine adenomyosis: A case report.

Carcinosarcoma arising from uterine adenomyosis is extremely rare. We encountered such a patient and herein provide a review of the literature. A 56-year-old woman was referred for a huge pelvic tumor, suspected to be an advanced uterine leiomyosarcoma. Intraoperative inspection revealed a mass, mainly located in the uterine myometrium, invading the uterine serosa. The tumor had previously spontaneously ruptured and disseminated to the pelvic cavity. Pathological and immunohistochemical examination revealed an infiltrative pattern of biphasic tumor cells composed of endometrioid adenocarcinoma and a nonepithelial component with rhabdomyosarcomatous differentiation. Benign endometrial glands with stromal cells were found adjacent to the area of the carcinosarcoma. The endometrium and both ovaries and fallopian tubes were microscopically free of tumor cells. The final diagnosis was heterologous type carcinosarcoma with rhabdomyosarcomatous differentiation, originating from uterine adenomyosis.