keratosis /ker′ətō″sis/ [Gk, keras + osis, condition] , any skin lesion in which there is overgrowth and thickening of the cornified epithelium. Approximately 20% of these skin lesions develop into squamous cell carcinoma. Prevention includes the use of sunscreen and the avoidance of drugs known to cause photosensitivity reactions. Kinds include actinic keratosis, seborrheic keratosis. −keratotic, adj.
