Cutaneous horns, also known by the Latin name cornu cutaneum, are unusual keratinous skin tumors with the appearance of horns, or sometimes of wood or coral. Formally, this is a clinical diagnosis for a "conical projection above the surface of the skin." They are usually small and localized but can, in very rare cases, be much larger. Although often benign, they can also be malignant or premalignant. Signs and symptoms
The lesion at the base of the keratin mound is benign in the majority of cases. Malignancy is present in up to 20% of cases, with squamous-cell carcinoma being the most common type. The incidence of squamous-cell carcinoma increases to 37% when the cutaneous horn is present on the penis. Tenderness at the base of the lesion often suggests the presence of a possible underlying squamous-cell carcinoma. Cause
The cause of cutaneous horns is still unknown, but it is believed that exposure to radiation can trigger the condition. This is evidenced by a higher rate of cases occurring on the face and hands, areas that are often exposed to sunlight. Other cases have reported cutaneous horns arising from burn scars. As with many other wart-like skin conditions, a link to the HPV virus family, especially the HPV-2 subtype has been suggested. Diagnosis
Cutaneous horn usually arises due to an underlying epidermal lesion, the most common being verruca vulgaris (wart), actinic keratosis (a potentially pre-malignant lesion of dysplastic keratinocytes), or squamous cell carcinoma (a form of skin cancer). These can look essentially identical clinically.
The Shope papilloma virus can cause rabbits to grow horns. This may have been the source of myths such as the Wolpertinger and the Jackalope. See also
Wart
Actinic keratosis
Epidermodysplasia verruciformis
List of cutaneous conditions

References
Further reading
Matthew Moore (2007-11-12). "Tree man who grew roots may be cured". London: Daily Telegraph. Archived from the original on 2007-11-13. Retrieved 2007-11-14. "Images of cutaneous horns". DermAtlas. Archived from the original on 2003-04-19. Retrieved 2007-11-14. DiClaudio, Dennis (2006) "The Hypochondriacs Pocket Guide to Horrible Diseases You Probably Already Have", Bloomsbury Publishing, ISBN 978-1-59691-061-4


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