Dysplastic nevus syndrome among Japanese. A case study and review of the Japanese literature.

Three Japanese families with dysplastic nevus syndrome (DNS) are reported. Each family had at least two members with multiple dysplastic nevi (DN). Family members with DN or multiple moles had paler skin than average Japanese, usually sunburned, and tanned less than average, whereas members with darker skin almost never had DN. Each of two families had one cutaneous malignant melanoma (CMM) patient associated with multiple DN. Both CMMs were on the leg. In Japanese DNS, skin color and sun sensitivity seem to be closely related to DN. The locations of CMMs associated with DNS were unique: No CMMs were found on acral areas where they most frequently occur in Japanese.