Seasonal prevalence of digital epiluminescence microscopy patterns in acquired melanocytic nevi

Available information of the effect of sun exposure on the biologic activity and morphologic characteristics of nevi is based on a few cross-sectional studies. According to these, nevi excised in summer show a higher mitotic count, a greater extent of the junctional component, and more frequent regression and inflammation.

Our goals were to obtain data on the seasonal prevalence of digital epiluminescence microscopy (D-ELM) patterns in acquired melanocytic nevi (AMN) and to test the reliability of D-ELM as a substitute for histology in prospective studies of the morphologic response of AMN to sun exposure.

Two independent series of AMN located on intermittently sun-exposed body sites and undergoing D-ELM in winter (n=121) and in summer (n=116) were compared for the prevalence of major ELM patterns.

Cases in the summer series showed a greater frequency of a broad and prominent pigment network; black dots with varied size, irregular distribution, and peripheral location; and peripheral depigmentation.

On the basis of known histologic correlates of D-ELM features, our findings were consistent with studies of seasonal histologic changes in AMN. D-ELM may be a useful tool in the prospective evaluation of effects of sun exposure on AMN morphology.