Malignant melanoma in situ: the flat, curable stage of malignant melanoma

Malignant melanoma can be diagnosed clinically and histologically when it is small, flat, and confined to the epidermis. The criteria for the diagnosis are described. The application of these criteria can lead to simple excision of the lesion and the prevention of the malignant melanoma from evolving into a neoplasm with the potential for metastasis.