Keratoacanthoma necessitating metacarpal amputation

Keratoacanthoma is usually considered a benign self-limiting lesion. First described in 1888 by Hutchinson, it most commonly involves the face and hands. It is usually controlled by complete soft tissue excision. A variant, subungual keratoacanthoma, affects bone by pressure erosion of the distal phalangeal tip. We report a case of keratoacanthoma clinically involving a metacarpal and phalanges with a radiologic and physical appearance at variance with previous reports. After multiple recurrences following erosion and cryosurgery, as well as attempted digit salvage with Mohs' surgery, ray amputation was required. The world literature pertaining to keratoacanthoma is reviewed and discussed.