A study of the solar effect on actinic keratoses by quantification of elastic fibres using an image analysis system

It is widely accepted that elastotic changes of the skin are primarily an indicator of cumulative sun exposure of the dermis and are a characteristic finding of actinic keratoses. To date, there have been few reports that measure the amount of elastic tissue objectively and quantitatively, especially in actinic keratoses. The computerized image analysis method has proved useful recently in determining the area of elastic fibres. Using this method, we objectively quantified the elastotic tissue in actinic keratoses and evaluated the relationship between the degree of dermal elastosis, epidermal atypia and histological types of actinic keratoses. Of the 28 actinic keratoses studied, the average percentage area of the elastic fibre was 40.48 ± 14.48 (mean ± SD) percentile. There was a 3.65-fold increase in the amount of elastic fibre in actinic keratoses compared with that of seborrhoeic keratoses occurring on the face (p < 0.00001). In addition, the more severe the atypia, the greater the area of elastic fibres in a representative section of the dermis. In conclusion, we observed that on quantitative assessment of elastic tissue in actinic keratoses, the percentage area of the elastic fibres in a representative section of the dermis ranges from 34.86 to 46.11%. This result may provide information for use in histological diagnosis of actinic keratoses and evidence for the possible role of sunlight in the pathogenesis of actinic keratosis.