Dermoscopy and methyl aminolevulinate: A study for detection and evaluation of field cancerization

Actinic keratosis (AK) is a keratinocyte intraepidermal neoplasia UV light – induced that frequently appears in sun-exposed areas of the skin. Although historically AK was de fi ned as “ precancerous ” , actually it is considered as the earliest stage of squamous cell carcinoma (SCC) in situ. Since AKs can progress into invasive SCC, their treatment isrecommended. AKsrarely developasa singlelesion;usually multiplelesions commonly affect anen- tire area of chronically actinic damaged skin. This has led to the concept of “ fi eld cancerization ” , an area chroni- cally sun-exposed that surrounds peripherally visible lesions, in which are individualized subclinical alterations. One of the main principles endpoint in the management of AKs is the evaluation and the treatment of fi eld cancerization. In this view, in order to detect and quantify fi eld cancerization, we employed a method based on the topical application of methyl aminolevulinate (MAL) and the detection of the fl uorescence emitted by its metabolite Protoporphyrin IX (PpIX); then, considering the extension and the intensity of measured fl uores- cence, we create a score of fi eld cancerization. The results show that patients underwent to daylight PDT had a reduction of total score, from T0 to T2. Whereas in the group untreated we observed a stability of total score or a slightly worse. So, the method and the score used allows to evaluate with a good approximation the dimension of fi eld cancerization and show the modi fi cation of it after treatment.