ABSTRACT
DEFINITION AND CLINICAL FEATURES A red, scaly plaque on light-exposed skin due to dysplastic epidermal keratinocytes. It may affect the face (including lower lip), bald pate (389), forearms, and dorsum of the hands, presenting as a red yellow or beige plaque, 0.5-1 cm in diameter, with surface scale or crust (390). It may ulcerate or develop a cutaneous horn. Frequently multiple. These lesions are common, especially in fair-skinned individuals over 40 years of age with a recreational or occupational history of chronic sun exposure. Enormous numbers may occur in those chronically immunosuppressed (e.g. renal transplant recipients). They carry a low risk of transformation to invasive squamous cell carcinoma.
