Differential diagnosis and treatment of pigmented skin lesions.

As a result of our improved understanding of the biologic importance of the various forms of pigmented skin lesions, we now have the ability to distinguish troublesome spots from those having no medical importance. These circumstances parallel an astronomical rise in the incidence of malignant melanoma. When evaluating the skin, attention to the concepts presented here will allow a high degree of accuracy in classifying moles in the benign or malignant category. For the most part, consideration of the lesion's border, shape, color, and size provides sufficient information with which to decide when a biopsy is warranted. Moles should never be destroyed by burning or freezing. If they are important enough to be removed, histologic verification of their nature must be obtained.