Squamous cell carcinoma, also known as squamous carcinoma, is a malignant tumor of the skin, which usually occurs in the exposed areas of the elderly, such as the face. It is often accompanied by foul odor. The causes of squamous carcinoma are mainly due to ultraviolet radiation, radiation or heat damage, and exposure to chemical carcinogens, such as coal tar and arsenic agents. Human papilloma virus infection also causes squamous carcinoma, and some precancerous lesions, such as solar keratosis and mucosal leukoplakia, can easily develop into squamous cell carcinoma; the treatment is mainly surgical excision.