SUBUNGUAL KERATOACANTHOMA

Subungual keratoacanthomas (SKA) differ in clinical presentation, biol ogical behaviour and the therapy needed from keratoacanthomas in other localizations. Against the backdrop of two personal observations and a review of the literature, the authors describe clinical and histolog ical features and also the differential diagnosis and therapy and this rare benign neoplasm. Patients present with a rapidly growing, painfu l subungual mass, which causes destruction of the underlying bone and usually does not regress spontaneously. Histological differentiation f rom squamous cell carcinoma is essential as the prognosis and treatmen t are different. SKA is treated by local excision and curettage. Erosi ons of the underlying distal phalanx usually heal spontaneously. Howev er, persistent recurrences after subtotal excision often necessitate a mputation of the distal phalanx.