Cutaneous horn (cornu cutaneum)

A cutaneous horn (Cornu Cutaneum) is a relatively rare tumour, most often arising on sun-exposed skin in elderly men, usually after the Vth decade. The tumor is often conical, consisting of marked retention of stratum corneum. This lesion can be caused by many primary underlying processes that may be benign, premalignant or malignant, thus the importance of accurate determination of the nature of the conditions at the base of the lesion. Surgery is the treatment of choice. We describe an illustrative case with cutaneous horn of the forearm. We also review various known causes of cutaneous horn and the pertinent literature.