Keratoacanthoma centrifugum marginatum. Aetiologic role of human papillomavirus and therapeutic effect of etretinate.

Introduction. Keratoacanthoma centrifugum marginatum is an uncommon keratoacanthoma of unknown etiology. We report a case suggesting a possible etiological role for a papillomavirus. Etretinate was an effective treatment.Case report. A 65-year-old woman had keratoacanthoma centrifugum marginatum of the antero-inferior aspect of the lower third of the right leg for 5 years. Fifteen years earlier, an infection had occurred at the same site after a trauma and was treated by oral antibiotics. Surgical exeresis was difficult due to the wide spread of the lesion. Etretinate given at an initial dose of 1 mg/kg/d for 6 weeks then reduced by half for 2 months led to nearly complete cure.Discussion. Keratoacanthoma centrifugum marginatum, verrucous carcinoma and epidermal carcinoma have some histological characteristics in common, suggesting a possible common etiological agent which could be certain strains of the human papillomavirus (HPV). In our case etretinate provided cure, possibly due to its antitumoral activity and perhaps due to its antiviral activity.The presence of koilocytes suggested HPV infection which was confirmed by PCR. This test does not however provide proof of the etiological role of HPV. We are currently studying the presence of HPV in keratoacanthomas and their possible etiological role.