Primary malignant melanoma arising in a cystic necrotic ovarian teratoma.

Cystic ovarian teratomas are common tumours. Malignant melanoma developing in a teratoma, however, is an extremely rare diagnosis. To date, only 24 cases have been reported in the literature. A 56-year-old patient underwent laparotomy for an ovarian tumour. Histopathologic examination revealed a primary malignant melanoma within a cystic necrotic teratoma, possibly arising from uveal cells. An extraovarian primary melanoma could not been found. After 7 months of operation metastasis to the vertebral column occurred, 2 months later liver metastases were diagnosed. The patient died of the disease 14 months after initial diagnosis.