Correspondence between dermoscopic features and epidermal structures revealed by scanning electron microscope.

It is already known that some typical dermoscopic patterns seen in melanocytic nevi on the sole have their own favorite site. In the weight-bearing area, melanocytic nevi with a parallel furrow pattern were preferentially observed. Those with a lattice-like pattern were observed in the arch area, whereas those with a crista reticulated pattern were seen in the border area. To investigate the relationship between the distribution of the dermoscopic patterns seen in plantar melanocytic nevi and the 3-D structures of the epidermis, the basal surfaces of the plantar epidermis from 14 skin lesions were observed by scanning electron microscopy (SEM). Our SEM observations revealed that transverse ridges formed a couple of parallel lamellae on the crista profunda limitans (limiting ridges). Between the limiting ridges and the crista profunda intermedia (intermediate ridges), the transverse ridges had different shapes according to the anatomical location of the sole. From these results, it was suggested that the characteristic dermoscopic patterns seen in acquired and junctional melanocytic nevi on the sole simulate the arrangement of transverse ridges.