A case of acquired dermal melanocytosis showing the manifestations of bilateral variant of nevus of Ito

There are a number of pigmentation disorders due to dermal melanocytes, including Mongolian spot, nevus of Ota, nevus of Ito and blue nevus, which usually appear at birth or in early childhood. But, several types of acquired dermal melanocytosis which usually appear in adult have been reported. A 67-year-old woman presented with asymptomatic, multiple, symmetric, bluish macules on the upper back for 10 years. Histopathologic findings showed some scattered spindle-shaped cells containing melanin pigment in the upper dermis and these cells were positive for S-100 protein stain. We suggest this case may be an acquired and bilateral variant of nevus of Ito considering the relationship between the acquired bilateral nevus of Ota-like macules and nevus of Ota.