Squamous cell carcinoma (SCC) of the skin is often asymptomatic, although patients may complain of itching or pain. SCC appears as a scaling, hyperkeratotic papule or nodule (Fig. 33-1). It is usually on sun-exposed skin and may ulcerate. Occasionally, SCC develops in sites of chronic inflammation or ulceration, as in discoid lupus erythematosus or hidradenitis suppurativa, or in sites of radiation therapy or burn. In these instances, the clinical appearance may be more subtle. Such SCCs are at high risk for recurrence or metastasis. Other high-risk sites are the lower lip, ear, digits, scalp, and penis. Recurrent SCC must also be considered in the high-risk group.