The management of congenital pigmented nevi.

Congenital nevi (CN) can be recognized at birth or shortly thereafter. In adults, only those nevi over 5 cm in diameter can be assumed to be congenital in the absence of documentation in infancy. CN cannot be identified with certainty by histological examination, nor can melanomas be presumed to originate from CN on the basis of histologic findings. Up to 5% of patients with large CN (as defined by the National Institutes of Health (NIH) consensus information) will develop melanoma, and 80% of these will appear before the age of seven years. Increased risk of melanoma from smaller CN has not been substantiated. Although total excision of large CN immediately following birth would reduce the approximate 5% risk for melanoma from these lesions, because of the complexity of the procedure, large lesion removal is seldom completed prior to the ages of 7 to 10 years, and nevus cells frequently remain at the base of the excision with resultant negligible risk reduction. Melanoma risk from large CN is predominantly risk of melanoma in childhood. CN do not contribute significantly to risk for adult melanoma. Sunburn constitutes the most important reducible risk factor for adult melanoma. Ultimately, the greatest hazard of large CN is not melanoma risk but cosmetic deformity.