When to worry about congenital melanocytic nevi

KAUAI, HAWAII – Children born with two or more melanocytic nevi of any size should have an MRI to check for brain lesions, ideally within the first 6 months, according to Jennifer Huang, MD, a pediatric dermatologist at Boston Children’s Hospital.

Two or more nevi increase the risk of CNS involvement, which in turn increases the risk of malignant conversion by more than 16-fold.

Dr. Jennifer Huang

Among the studies she cited was a 2017 literature review of 448 children with congenital nevi, 10 of whom developed melanoma: It arose in the skin in 2, the brain in 6, and an unknown location in 2. All 10 children were born with two or more nevi, and not all of them had large or giant nevi, which is a known risk factor for malignant conversion (Br J Dermatol. 2017 May;176[5]:1131-43).