Paget's disease of the nipple simulating malignant melanoma in a black woman.

A lesion of Paget's disease arising in the skin of the nipple in a black woman is reported. The lesion simulated histologically a malignant melanoma because of the abundance of melanin within neoplastic cells in the epidermis as well as within the underlying ductal carcinoma of the breast. It was only after differential staining that the diagnosis of Paget's disease could be substantiated unequivocally.