Circumscribed, solar precancerous damage to the skin of fair-skinned, light-sensitive people caused by chronic cumulative exposure to light (> 10 to 60 years).
Actinic keratoses are so-called precanceroses, i.e. non-invasive, early (in situ) squamous cell carcinomas. This view is underlined by new names such as SCC of the actinic keratosis type (squamous cell carcinoma in situ) or KIN (keratinocytic intraepidermal neoplasia).