Histologic patterns of congenital nevocytic nevi and implications for treatment.

The therapeutic problems associated with congenital nevocytic nevi (CNN) have lead to a flurry of interest in neonatal dermabrasion. This is based on the theory that nevus cells at birth are superficial and accessible to dermabrasion and that they later migrate into the deeper dermis. We studied twelve patients with CNN, including seven patients less than 3 months of age, with serial biopsies taken over a period of 15 months. In addition, four neonates with giant CNN underwent dermabrasion, and biopsies were obtained pre- and postoperatively. The histologic features of CNN and the implications for treatment are discussed. Our results are inconsistent with the idea of migration of nevus cells into the dermis during infancy. Dermabrasion of giant CNN at an early age may improve the cosmetic appearance; however, it will not remove most nevus cells and is not recommended as an effective treatment for the prevention of melanoma.