Cutaneous horn: A mask to underlying malignancy.

Cutaneous horns ( cornu cutaneum ) are uncommon lesions consisting of keratotic material resembling that of an animal horn. It is a conical- or cylindrical-shaped excessive hyperkeratosis of variable size ranging from few millimeters to several centimeters with a variable in size and shape, such as cylindrical, conical, pointed, transversely or longitudinally corrugated, or curved like a ram's horn. The lesions typically occur in sun-exposed areas, particularly the face, ear, nose, forearms and dorsum of hands. Even though 60% of the cutaneous horns are benign in nature, the possibility of skin cancer should always be kept in mind. The clinical diagnosis includes various benign and malignant lesions at its base. Lesions associated with cutaneous horn are keratosis, sebaceous molluscum, verruca, trichilemmal, Bowen's disease, epidermoid carcinoma, malignant melanoma and basal cell carcinoma. Herewith, we report a case of cutaneous horn on the upper lip vermillion masking the underlying malignancy at its base.