Subungual keratoacanthoma

Subungual keratoacanthoma is a rare tumor with some features at variance with keratocanthoma elsewhere. It is a painful or tender lesion that shows little or no tendency to spontaneous involution. The terminal tuft of the distal phalanx is destroyed by pressure erosion. Clinically, subungual keratoacanthoma and subungual squamous cell carcinoma have many features in common. A distinction must be made histologically.