Actinic keratosis are of utmost medical and economical interest because of their high prevalence (20 % of 60 year-old people and older in the Northern hemisphere) and their important cosmetic impact as such actinic keratosis mostly appear on photo-exposed skin sites. The surgeon in charge of such lesions' removal (i) some actinic keratosis adjoining carcinoma to be resected therefore causing the problem of functional areas damaging (eyelids, lips, etc.) or (ii) numerous actinic keratosis localized away from carcinoma (photo-carcinogenesis field) faces the issue of clinical evaluation of such lesions: which ones will spontaneously regress (it is supposed to be the case for 20 % of such lesions);which ones will remain and which ones will develop into invasive carcinomas ?