Cutaneous horn

Cutaneous horn
Actinic keratosis, pre-cancerous area of thick, scaly, or crusty skin (Below) with cutaneous horn tissue (above)

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."^[1] 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.^[2]