Abstract
Actinic keratosis (AK) is known as a premalignant skin cancer, which is caused by an excessive exposure to the sun. The clinical feature is not a single one, but definitely characteristic of keratinization with somewhat color change.There are five major appearances, namely erythematous, pigmented, keratopapular, verrucous and cutaneous horn. The final histopathological diagnosis of AKs are grouped as three types: hypertrophic, atrophic and bowenoid. Acantholytic feature is often encountered, and that is a significant sign of a tendency toward a development of invasive carcinoma (squamous cell carcinoma, SCC) . There are also several special histologic types of AKs. Treatment for the care of AKs has been done in different ways, and as most of them are destructive, so no excised specimens can be obtained. I recommend the best way against AKs is a non-destructive surgical maneuver, which makes the specimen histopathological discussion. Shave excision is a satisfactory way, because it is simple without any special instruments and a possible biopsy. AK is a fearless tumor of carcinoma in situ, but an exact precursor of SCC. [Skin Cancer (Japan) 2003; 18: 106-114]
