A case of cutaneous horn originating from keratoacanthoma.

Cutaneous horn is the clinical description of a hyperproliferation of compact keratin in response to a wide array of underlying benign and malignant pathologic changes. We report here on a case of cutaneous horn that originated from keratoacanthoma in a 76-year-old woman. Grossly, a 2.5×0.7 cm sized yellow-white colored scaly fungating mass from an erythematous nodule was observed on the right temporal area. Histopathologically, it was reported as keratoacanthoma with cutaneous horn. The lesion was totally excised after the diagnosis.