Topical photodynamic therapy using intense pulsed light for treatment of actinic keratosis: Clinical and histopathologic evaluation

BACKGROUND. Photodynamic therapy (PDT) is suitable for the treatment of actinic keratosis, and, recently, topical PDT using intense pulsed light as a light source has been reported. However, evaluations of its therapeutic effects have been clinically based. OBJECTIVE. The objective of this study was to confirm the histopathologic resolution of actinic keratosis treated by topical PDT using intense pulsed light as a light source. METHODS. Twelve actinic keratosis lesions in seven patients were treated with 5-aminolevulinic acid-PDT using intense pulsed light as a light source. After a single treatment, the clinical response was assessed and histopathologic examinations were performed on clinically resolved lesions. RESULTS. Six of 12 (50%) lesions showed clinical clearance after a single treatment, but histologic examinations showed that only 5 of the 12 (42%) lesions had been removed. No complications, such as pigmentary changes or scarring, were observed. CONCLUSION. Intense pulsed light is potentially an effective light source for PDT. However, the determination of complete remission in actinic keratosis requires caution, and long-term follow-up or histologic confirmation may be required.