Ovarian malignant melanoma: a clinicopathologic study of 5 cases

Primary ovarian malignant melanomas are extremely rare. The wide range of morphologic appearances assumed by melanomas in the ovary can cause considerable difficulty in diagnosis. The clinicopathologic features of 4 definite and 1 probable primary ovarian melanomas are presented. The patients ranged in age from 41 to 71 years. Four tumors were within teratomas with 2 showing a lentiginous pattern of melanoma in the squamous epithelium. Unusual histologic features were noted. Immunostains for S-100, HMB-45, and Melan-A were positive in all tumors. Premelanosomes were identified in 2 tumors ultrastructurally. Metastatic sites included regional nodes, peritoneal surfaces, omentum, lung, liver, brain, and bone. All 5 patients died within 18 months. Immunohistochemistry and electron microscopy aid considerably in the diagnosis of ovarian melanomas where pigmentation or teratomatous elements are absent. Familiarity with the wide range of morphologic patterns presented here will raise awareness and facilitate detection of future cases of ovarian melanoma.