Cutaneous horn

A cutaneous horn (CH) is not a diagnosis, but a clinical presentation of a rough, horny plug or outgrowth of epidermal origin.

This chapter is set out as follows:

• Although a cutaneous horn can arise from a viral wart, seborrhoeic keratosis or actinic keratosis, 15% will arise from an underlying squamous cell carcinoma (SCC)

• Benign lesions tend to be asymptomatic unless they catch
• An SCC underlying a cutaneous horn may be tender 

Distribution

• Most common on UV-exposed sites

Morphology

• A raised, rough, firm, white-yellow, horn-like lesion
• Benign lesions (or actinic keratosis) - the horn is flush with the skin surface
• SCC (or bowenoid actinic keratosis) can have the following features - the presence of a raised lump (papule or nodule) underneath the horn, induration, tenderness (other than when the lesion is caught on something), or surrounding inflammation 

• If an SCC is suspected the patient should be referred urgently to Secondary Care (two-week wait)

• Lesions with a benign appearance can be treated by curettage or excision and sent for histology to rule out an SCC. If curettage is used, a deep enough sample must be obtained in order to obtain an accurate histological diagnosis. For small lesions cryosurgery may suffice