Cutaneous horn due to cutaneous squamous cell carcinoma

A 91‐year‐old man presented with a more than 10‐year history of a slow growing horn‐like lesion on the right side of the face. The patient denied pruritus, pain, or any other symptoms. Physical examination revealed a grey‐brown, firm, keratotic cutaneous horn 8cm long (Figure, A). The lesion was entirely excised surgically. Histopathology showed atypical keratinocytes and horn pearls within the dermis, with hyperchromatic and pleomorphic nuclei (Figure, B, arrows). A diagnosis of cutaneous horn due to well differentiated squamous cell carcinoma was made. Cutaneous horn is a reactive cutaneous growth caused by a variety of benign or malignant primary diseases, including squamous cell carcinoma, actinic keratosis, keratoacanthoma, Bowen disease, basal cell carcinoma, Kaposi sarcoma, viral warts, and seborrhoeic keratosis.1,2 Therefore, pathological examination is necessary for identifying primary disease.1,2 The most common treatment option is surgery. Other options are available if the lesion is small with a low suspicion of malignancy, such as electrocautery, cryotherapy, carbon dioxide laser, and Nd YAG laser.3