Malignant melanoma arising in an ovarian carcinosarcoma: case report and review of the literature.

A case of ovarian malignant mixed mullerian tumor (MMMT) with melanocytic differentiation is described. A 74-year-old woman presented with left lower quadrant pain. Pathologic examination of the left ovary revealed a MMMT, composed predominantly of serous carcinoma (90%) with a minor sarcoma component containing focal chondroid differentiation. There was also a single focus of malignant melanoma. Immunohistochemical studies showed that the latter was positive for S-100, HMB-45, and pan-melanoma cocktail, and was negative for synaptophysin and neuron-specific enolase. To the best of our knowledge, this is the first case of MMMT with melanocytic differentiation described in the ovary.