Classification of melanocytic nevi

This project is a multicenter study in which we will investigate a dual concept of nevogenesis that have been raised recently by our group. Study location is the Department of Dermatology at the Medical University of Graz in close collaboration with centers in Austria (Vienna), Italy (Naples, Benevento, Modena), Spain (Barcelona) and the United States (New York). The background for this project is based on the hypothesis that small congenital melanocytic nevi (CMN), "early" acquired melanocytic nevi in childhood (AMN) and dermal nevi, all dermoscopically characterized by globular pattern, belong to the same spectrum of genetically determined melanocytic proliferations that develop due to endogeneous pathways with persistence through lifetime, in contrast to "true" acquired melanocytic nevi, dermoscopically showing reticular pattern, that develop due to exogeneous factors such as UV-exposure with disappearance due to regression/involution later in life. The investigations to this study will comprise three arms: 1. This arm will contain a training phase and a test phase, in order to elaborate specific clinical-dermoscopic- histopathologic criteria of the small CMN, "early" AMN and dermal nevi (all typified by globular pattern) and reticular typed AMN that should achieve a sufficient reproducibility and validity among clinicians and pathologists. Study location: All centers involved 2. This arm will verify whether small CMN, "early" AMN and dermal nevi, characterized by globular pattern differ in their genetic alterations compared to reticular typed nevi This study arm is based on the hypothesis that "globular" AMN in children may represent a particular subset of nevi that develop due to endogenous pathways, in contrast to the "reticular" AMN in adults that seem to develop in response to UV-exposure. Given credibility to this hypothesis, it will be expected that globular typed nevi and eventually dermal nevi lack B-RAF mutations whereas reticular nevi show alterations in the B-RAF gene. Study location: Graz 3. This arm will test whether reflectance confocal microscopy (RCM) will give new insights into the migration of melanocytes. Small CMN, globular typed nevi and if present reticular typed nevi in 5 to 10 children, younger than 10 years and individuals older than 30 years, will be followed up using RCM in order to obtain new insights into the migration of melanocytes (downward and/or upward migration) as it has been proposed by the two concepts of nevus evolution namely, the Abtropfungs- and Hochsteigerungs- theories Study location: Graz, Barcelona, Modena, New York Endpoint: This study will verify, whether melanocytic nevi follow distinct pathways in their evolution. If the investigations will raise evidence for the validity of this hypothesis, a new classification, based on combined clinico-dermoscopic-histopathologic-genetic background of melanocytic nevi will be proposed, in order to better differentiate melanocytic nevi and to estimate their potential to develop into a melanoma.