Multiple agminate Spitz nevi.

A five-year-old boy had multiple agminate Spitz nevi arising in an area of hyperpigmentation that developed concurrently with the nevi. Multiple Spitz nevi occurring in a single group are rare, and their presence on a hyperpigmented background is extremely uncommon. Very few such cases have been described, and all of those lesions arose on a congenital hyperpigmented patch. In contrast, the nevi in our patient appeared to arise on an acquired hyperpigmented patch that was not present at birth, and histologically did not demonstrate features of a congenital nevus. Accurate diagnosis is necessary to avoid unnecessary radical therapy.