Practical application of the new classification scheme for congenital melanocytic nevi

A new consensus-based classification of congenital melanocytic nevi (CMN) has recently been proposed. It includes categories for projected adult size (PAS) and location, satellite nevi counts, and morphologic characteristics (color heterogeneity, rugosity, nodularity, and hypertrichosis). The objective of the current study was to test the applicability of the new categorization scheme and to correlate classification outcome with the patient's history of melanoma and neurocutaneous melanocytosis (NCM). Children and adults with CMN attending a patient conference in Dallas, Texas, in 2012 were invited to participate in the study. Anamnestical data were collected using a standardized questionnaire. Two dermatologists performed clinical examinations. Of 45 patients enrolled, 33 had a giant CMN (G1 [>40 cm PAS], n = 13; G2 [>60 cm PAS], n = 20), 12 had an NCM (5 symptomatic, 7 asymptomatic), and 1 had a history of melanoma. CMN size was positively correlated with NCM (p < 0.05). The classification system allowed an easy and detailed phenotypic characterization of each individual CMN. CMN size and morphology were difficult to assess in patients after surgical removal, and the number of satellite nevi at birth or during infancy was not always known. Our report provides practical aids for the application of the newly proposed CMN classification. Prospective evaluation of accurately classified patients in CMN registries will reveal the predictive value of the scheme. The small study sample limits meaningful conclusions regarding the correlation between CMN parameters and the risk of NCM and melanoma.