Assessing field cancerization and actinic keratosis using ultraviolet-induced fluorescence dermatoscopy after the application of 5-aminolevulinic acid – An observational study

Abstract

BackgroundActinic keratoses (AK) are one of the most frequent reasons for consultations in dermatology. Ultraviolet-induced fluorescence dermatoscopy (UVFD) is a new method that allows the assessment of lesions in a spectrum of light that originates from the fluorochromes emitting UV-excited luminescence. The aim of this study was to assess the UVFD features of AKs before PDT and their intensity in field cancerization and single lesions. MethodsThis retrospective study was conducted from June to November 2023. Lesions were assessed with the Olsen scale clinically and dermatoscopically (DermLite DL5, 10x magnification) and photographed. UVFD fluorescence was categorized as ‘none’, ‘weak’, ‘moderate’, and ‘intense’. A 1-mm thick layer of 10 % 5-ALA gel was applied to single lesions or cancerization field (depending on the patient) and covered with an occlusive dressing for 3 h. Prior the application of 10 % 5-ALA gel, the lesions were degreased with an alcoholic solution. The occlusion was removed, and the field was cleaned with a 0,9 % saline solution. Afterward, each lesion was photographed in polarized light and UVFD mode. ResultsA total of 194 dermatoscopic images were analyzed, 111 corresponded to field cancerization and 81 to single AKs. Overall, weak fluorescence was noticed in 22 of them (11,3 %), moderate in 107 (55,15 %), and intense in 65 (33,5 %). Amongst field cancerization (111 images), weak fluorescence was seen in 11 (9.9 %), moderate in 68 (61,26 %), and intense in 32 (28,82 %). In single lesions (81 images), weak fluorescence was detected in 11 (13,2 %), moderate in 39 (46,99 %), and intense in 33 (28.83 %) of the lesions. Slightly more intense fluorescence was noticed in higher Olsen grade (p = 0.04). ConclusionsUVFD can enhance our efficacy of pre-procedural examination and might arise as a useful device to predict the therapeutic effect of PDT.