[An autopsy case of primary malignant melanoma of the ovary].

This report presents the first patient in Japan with primary malignant melanoma of the ovary. The patient was a 62-year-old woman with the complaint of progressive left hemiparesis due to metastatic brain tumor. She died in the course of two months. At autopsy, there was a large tumor containing brownish fluid at the right ovary. The inner lining of the tumor was covered with a black friable mass with hairs. Histologically, the tumor was composed of polygonal, melanotic or amelanotic cells. Metastases were found in the cerebrum, uterine cervix, etc. In conclusion, the tumor was thought to be malignant melanoma arising in a dermoid cyst. This is an extremely rare condition, reported in only 12 cases throughout the world. The histological findings and histogenesis are presented and discussed.