Two types of pattern modification detected on the follow-up of benign melanocytic skin lesions by digitized epiluminescence microscopy.

Abstract

Digital epiluminescence microscopy (DELM) is currently being developed for the diagnosis of pigmented skin lesions (PSL) and the early diagnosis of malignant melanoma. So far there are only few studies documenting if modifications in PSL may be detected by DELM over time. Our purpose was to determine if DELM is an adequate tool for the follow-up of PSL and if any detectable modifications occur within PSL over time. We followed 150 PSL over 2 years in 67 patients using a DELM system. At the end of the follow-up period, the retrieved DELM images were analysed by two observers and evaluated for the presence and type of modifications. Modifications were observed in 69% of the PSL. These modifications were of two types. Type 1 corresponded to an increase in the pigment content of the lesion without modification of either its size or architecture, and was probably related to sun-related seasonal variation. Type 2 included an increase in the size and various variations in the architecture, corresponding to a progression of the lesion. Correlation of the type of modification with the type of PSL, as defined by its epiluminescence microscopy (ELM) patterns, indicated that type 2 modifications were associated with lesions initially showing ELM signs of 'dysplasia', whereas lesions showing only type 1 modifications did not show such patterns. We have documented the feasibility of following up PSL with DELM. The pattern of modification of a PSL over time could be correlated with its nature.