Cutaneous horns: a histopathologic study.

We report a series of 230 cutaneous horns, of which fewer than one fourth were frankly malignant. Actinic keratoses were the lesions most commonly found underlying cutaneous horns (37.39%). Cutaneous horns overlying a benign lichenoid keratosis, epidermolytic hyperkeratosis, trichilemmoma, an epidermal inclusion cyst, and a benign fibroma are reported. Three cases were nondiagnosable because of inadequate biopsies that were too superficial to show the base of the lesion.