Leg ulcers: a common problem with sometimes uncommon etiologies.

In the U.S., leg ulcers present a significant clinical problem, occurring at a rate of approximately 600,000 new cases per year. In most cases, the cause of ulceration is venous or arterial in nature. One uncommon but significant cause of leg ulcers is sqaumous cell carcinoma (SCC). Although the incidence of SCC is higher in white than black populations, blacks with SCC typically exhibit involvement of areas of the skin that are not chronically sun-exposed, especially the lower extremeties. Predisposing factors include burn scars, chronic infection or ulceration, and chronic discoid lupus erythematosus. Leg ulcers of atypical presentation or those that fail to heal should alert the clinician to consider uncommon etiologies.