Fig. 1

Example of histologic measurement of nevus depth. H&E stained (×40), used for histopathological measurement of infiltration depth in this work. The depth of deepest-seated nevus cells perpendicular to the skin surface is measured. A, A 95-month-old female patient underwent surgical excision for a 20–29.9 cm large nevus in the proximal extremity. The thickness of the nevus at a randomly selected point was 0.67 mm. B, A 47-month-old male patient underwent surgical excision for a giant nevus sized 30–39.9 cm in the trunk. The thickness of the nevus at randomly selected points is 3.79 mm