Case report of a challenging medium-sized congenital melanocytic nevus (CMN): Highlighting a role for reflectance confocal microscopy (RCM) for evaluating changing CMN in children.

A 3.5-month-old boy presented with a changing medium-sized congenital melanocytic nevus on his leg. Due to atypical features on dermoscopy and reflectance confocal microscopy (RCM), an excision of the area of concern was performed. Histopathology showed many of the pathological features usually associated with a diagnosis of melanoma in situ in older patients, but due to the young age of the patient, absence of mitoses, and the degree of atypia, a diagnosis of a dysplastic compound nevus arising in a congenital compound (predominantly dermal) nevus was favored. In our case, RCM corresponded to histopathology helped target the area of concern and map the clinical and subclinical components to facilitate an optimal biopsy.