Seasonal prevalence of digital epiluminescence microscopy patterns in acquired melanocytic nevi

Background: Available information on 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. Objective: 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. Methods: 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. Results: 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. Conclusion: 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.