[Cutaneous horn, actinic keratosis and squamous cell carcinoma. Presentation of a clinical case].

The cutaneous horn is defined as a tumour, usually of conical appearance which prevails over the length of its diameter, with large hyperkeratosis in its extreme and due to varied causes. It may be associated with benign, pre-malignant (actinic keratosis) and malignant (squamous cell carcinoma) skin, usually requiring complete excision of the lesion and a histopathological examination. We report a case of a 94 year old woman with a cutaneous horn and an initial pathological diagnosis of actinic keratosis, which subsequently progressed to squamous cell carcinoma, along with and a brief review of the literature. The treatment is complete excision of the lesion, deepening its base due to the likelihood of association with malignant lesions.