Actinic keratosis underlying cutaneous horn at an unusual site-a case report.

Cutaneous horns are usually found on chronic sun-damaged skin. A cutaneous horn is a rare tumour, often conical, circumscribed, and composed of dead keratin usually derived from base keratinocytes. It occurs mainly in association with underlying benign, premalignant, and malignant cutaneous diseases. The commonest malignancy is squamous cell carcinoma. Thus, to accurately ascertain the nature of the condition at the base of the lesion and to rule out malignancy, an excision biopsy is indicated. Here, we report a case of cutaneous horn over the palmar aspect of the left middle finger in a 45-year-old man whose histopathology showed actinic keratosis.