actinic keratosis, a slowly developing, localized thickening and scaling of the outer layers of the skin as a result of chronic, prolonged exposure to the sun. It is more common in the fair skinned and elderly. It usually is a discrete, slightly raised, red-on-pink lesion located on a sun-exposed surface. Treatment of this premalignant lesion includes surgical excision, cryotherapy, and topical chemotherapy. Also called senile keratosis, senile wart, solar keratosis.
