Dysplastic nevi (DN), also called Clark’s nevi, or atypical nevi, are asymptomatic. Patients may have only a single lesion or hundreds of them. DN are macules at least 5 mm in diameter with variable pigmentation, indistinct margins, and irregular, asymmetric outline (Fig. 40-1). Pigmentation frequently includes shades of brown and red and occasionally some black. The pigment variability is usually less than what is seen with malignant melanoma. The most common site is the back. Patients with many lesions (dysplastic nevus syndrome) have DN anywhere on the trunk and also on the proximal extremities and scalp (Fig. 40-2). Pruritus or bleeding in any nevus may be associated with transformation to melanoma.