Precursors to Malignant Melanoma: Congenital and Dysplastic Nevi

It has become evident during the past few years that there are two types of nevi that are predisposed to develop cutaneous melanoma. The incidence of malignant melanoma has been rising over the past decade. It is now clear that conservative excision is curative for virtually all thin tumors. Precursor lesions—congenital and dysplastic nevi—and most melanomas can be detected by careful inspection of the skin. Identification and appropriate treatment of such atypical melanocytic lesions are tantamount to saving a patient's life, for aside from surgery, no other effective therapy exists. The physical examination of all patients should include evaluation of their entire cutaneous surface for unusual pigmented areas. Evaluation for melanoma or precursors will often include biopsy or excision or, if the lesion is to be reassessed periodically, a photograph to document its appearance. The Figures presented here and the accompanying National Institutes of Health consensus statement will guide clinicians