Myths and misconceptions: the risk of melanoma in small congenital nevi.

A 2-year-old boy presents with a 4 x 3-cm, darkly pigmented nevus on his back. His mother states that this lesion has been present since birth. Both parents noticed that the nevus has become slightly larger but deny any other changes in its appearance. The boy is otherwise healthy. He has no allergies and does not take any medication. There is no family history of skin disease or cutaneous malignancy. The parents are concerned about the melanoma risk in their child's congenital nevus.