views updated

keratosis (ke-ră-toh-sis) n. a horny overgrowth of the skin. actinic (or solar) k. a red spot with a scaly surface, which may occasionally become malignant. These spots are found in older fair-skinned people who have been chronically overexposed to the sun. seborrhoeic k. (basal-cell papilloma) a superficial yellowish spot that never becomes malignant. Such spots occur especially on the trunk in middle age, slowly darkening and becoming warty over the years.