A cutaneous horn is more a sign than a specific diagnosis. Cutaneous horns are hyperkeratotic, conical projections from the skin arising from benign or malignant lesions. They can occur almost anywhere on the skin but are more commonly found on sun-exposed surfaces.

A common cause of a cutaneous horn is an actinic keratosis at the base of the horn; a cutaneous horn caused by an actinic keratosis must be distinguished from one arising from a squamous cell carcinoma (SCC), which may be present at the base of a cutaneous horn.

Cutaneous horns most frequently occur in elderly individuals, though they are occasionally seen in children (almost always as warts). In adults, the most common scenario is a cutaneous horn of the face, scalp, or ear presenting with a SCC at the base. Warts and seborrheic keratoses are common benign lesions that may also be seen at the base of a cutaneous horn.

Immunocompromised Patient Considerations:
Immunocompromised patients are prone to SCC, especially on sun-exposed areas, and these may present as cutaneous horns.

Pediatric Patient Considerations:
When cutaneous horns occur in children, a wart is frequently the cause.