Relationship between the Three-Dimensional Structure of the Human Plantar Epidermis and the Dermoscopic Patterns Seen in Melanocytic Nevi

Objective: Our aim was to investigate the relationship between the distribution of the dermoscopic patterns seen in plantar melanocytic nevi and the 3-dimensional structures of the epidermis. Methods: The precise locations of 69 melanocytic nevi on the sole and the border areas were investigated, with attention paid to each dermoscopic pattern. In addition, the basal surfaces of the plantar epidermis from 14 anatomical areas were observed by scanning electron microscopy (SEM). Results: In the weight-bearing area, melanocytic nevi with a fibrillar 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. On SEM observations, 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. Conclusion: These results suggest that the characteristic dermoscopic patterns seen in plantar melanocytic nevi simulate the arrangement of transverse ridges.