also called solar keratosis; the plural is keratoses (kair-uh-TOE-seez). A rough or scaly area of skin that can develop after years of sun exposure. They are benign (not cancer), but over time a few will develop into squamous cell cancer (a type of skin cancer). Doctors can remove them or destroy them with cold, lasers, chemicals, or creams. See also squamous cell carcinoma.