The Morphologic Universe of Melanocytic Nevi

Different types of nevi do exist in relation to their epidemiology, morphology, evolution, and associated melanoma risk. The introduction of dermoscopy opened a new dimension of the morphologic universe of nevi and allowed clinicians to observe colors and structures within nevi that are otherwise not visible to the unaided eye. Because most of these colors and structures correspond to well-defined histopathologic correlates, dermoscopy enables clinicians to date to more precisely predict the histopathology diagnosis and thereby improve on their clinical diagnostic accuracy. Besides the diagnostic impact, the in vivo observation of thousands of nevi using dermoscopy and digital dermoscopic follow-up has opened new understanding about the evolution of nevi and factors influencing the nevus pattern. In consequence, a new nevus classification has been proposed, subdividing nevi into 7 categories, which are as follows: (1) globular/cobblestone nevi, (2) reticular nevi, (3) starburst nevi, (4) homogeneous blue nevi, (5) nevi on special body sites, (6) nevi with special features, and (7) and unclassifiable melanocytic proliferations. This article provides an overview on the morphologic classification of nevi and the factors influencing the nevus pattern. Semin Cutan Med Surg 28:149-156 (C) 2009 Elsevier Inc. All rights reserved.