Keratoacanthoma centrifugum marginatum arising from a scar after skin injury.

Among the variants of solitary keratoacanthoma, keratoacanthoma centrifugum marginatum (KCM) is characterized by the lack of a tendency toward spontaneous remission and by continuous centrifugal spread. We describe a case of KCM arising from the scar after an old skin injury. The lesion appeared on the dorsum of the right hand, grew peripherally for 30 months, and became a tumor with a multinodular margin and central atrophy. A biopsy specimen from the edge of the tumor showed features resembling typical solitary keratoacanthoma.