Primary peritoneal carcinosarcoma arising from the secondary Müllerian system: case report and literature review

Carcinosarcomas, also known as malignant mixed Müllerian tumours (MMMT), are aggressive neoplasms that are biphasic as they contain both carcinomatous and sarcomatous elements. Most commonly arising from the endometrium, extragenital carcinosarcomas are extremely rare and most cases develop from the peritoneum. The case is reported of a 70-year-old female who presented with abdominal pain and distention. On evaluation a large abdomino-pelvic mass with ascites was noted. She underwent complete cytoreductive surgery and the histopathology reported carcinosarcoma of primary peritoneal origin, of heterologous type arising de novo from the secondary Müllerian system with no synchronous or metachronous carcinomas or endometriosis. She declined adjuvant treatment and re-presented with disseminated abdominal disease and unfortunately succumbed to the disease within four months. Carcinosarcomas of the extragenital sites have been postulated to arise from pre-existing foci of endometriosis, Müllerian duct remnants, or the secondary Müllerian system, all of which are derivatives of the coelomic epithelium. They are extremely aggressive, and there is little knowledge concerning their natural history and scant data regarding their management.