Pinto-Almeida, T.Oliveira, A.Velho, G.Alves, R.Caetano, M.Selores, M.2014-09-022014-09-022011Dermatology Online Journal 17 (12): 101087-2108http://hdl.handle.net/10400.16/1662Cutaneous horn is a conical hyperkeratotic projection of the skin composed of compact keratin. A wide range of pathologic conditions may be found at its base, including a significant proportion of malignant tumors. A notable, giant cutaneous horn uncovering a keratoacanthoma/well-differentiated squamous cell carcinoma is presented, highlighting the importance of histopathological examination to rule out malignancy because clinical features cannot assure a correct diagnosis.engjournal article