Histopathological features of photodamage and mast cell infiltrate in actinic cheilitis with different grades of epithelial dysplasia

Background: Actinic cheilitis is induced by chronic exposure to ultraviolet radiation and shows solar elastosis, a feature that has been associated with mast cell infiltrates. This study aimed to investigate the area of solar elastosis, collagen loss, and mast cell infiltrates in a series of actinic cheilitis.

Methods: We evaluated the epithelial dysplasia in 52 cases of actinic cheilitis and the solar elastosis with Weigert's resorcin-fuchsin. Collagen loss was evaluated with Picrosirius red, analyzed under polarized microscopy, and scored from 1 to 3. Elastosis proportionate area (EPA) was calculated with image software. Mast cells were highlighted with toluidine blue stain.

Results: EPA varied from 2% to 45%, with a mean of 17.1% in the cases, with no differences among epithelial dysplasia degrees. Most cases presented collagen loss scores of 2 or 3, and higher loss of type I collagen was associated with older age. Mast cell density was higher in severe epithelial dysplasia (P = 0.002) and in high-risk cases (P = 0.01).

Conclusion: Actinic cheilitis presented variable EPA and marked loss of type I collagen; however, these features were not associated with the degrees of epithelial dysplasia. Besides, mast cell density increased with epithelial dysplasia worsening and this was not associated with elastosis area or collagen loss.