Black lesions of the skin.

Benign melanocytic lesions include lentigo, ephelid (freckle), pigmented nevus, sacral spot, blue nevus, and combined nevus and blue nevus. Malignant melanocytic lesions are melanomas, which arise from melanocytes at the epidermodermal junction, or, rarely, from blue nevi. They usually originate in brown plaques known as lentigo maligna, in pigmented nevi, or in normal skin. Melanoma is diagnosed clinically in less than 50 per cent of instances. Biopsy is therefore of great importance, since practically all melanoma can be cured by adequate early resection.