Spitz nevus on the sole of the foot presenting with transepidermal elimination

Abstract

A 10-year-old Japanese girl presented with a rhomboid-shaped brown macule, 4 x 3 mm in size, on the sole of the right foot. Dermoscopic examination revealed a number of black dots and globules on the ridges of the skin, marking an area of symmetrical brown pigmentation. On the periphery, a streak-like arrangement of black dots/globules on the brown pigmentation was observed along the ridges, simulating a “starburst” pattern. The lesion was excised and histological examination showed a symmetrical wedge-shaped compound melanocytic lesion that consisted of junctional and intradermal nests of a mixture of large spindle and epithelioid cells. None of the cells were atypical, and maturation of the cells with increasing depth was observed. From these findings, a diagnosis of Spitz nevus was made. Transepidermal elimination of nevus cell nests was observed and there were small groups of degenerated melanin-laden cells in the cornified layer. Masson Fontana stain revealed fine melanin deposits in the nevus cells of the junctional and intradermal nests, as well as heavy melanin deposits in the small groups of degenerated cells in the cornified layer. The distribution of melanin may contribute to a unique dermoscopic finding in this case.

Keywords

• dermoscopy
• histopathology
• Spitz nevus
• transepidermal elimination