Mechanism of Repigmentation of Halo Region

Abstract

In halo neves, the central mole was gradually seen fading without repigmentation after being removed and brought back to its original place. However, when 8-MOP was administrated and solar irradiation was performed after the same treatment, no repigmentation from the mole was observed. In some cases, moles decreased in size from the margin of the halo. When a healthy skin graft was transplanted to the halo, and while the mole was left alone, repigmentation was seen in the halo region. But repigmentation was observed soon after the central mole was replaced with a healthy skin graft. A healthy skin graft was transplanted to the halo region when the central mole was left alone. After 4 years and a half, the central mole faded. At this time, the central mole was removed and examined histologically. Nevus cell nests were noted in corium and a few melanin were left in superficial layer. No other particular findings were observed. On the other hand cellular invasion was not seen in the circumference of the nevus cell nest, a process of destruction was observed in the central part of the nevus.