THE ORIGINS OF ODONTOGENIC KERATOCYST BASED ON THE DISTRIBUTION OF MELANOCYTES

Abstract

Objectives Melanocytes are pigmented-producing cells and derived from the neural crest. Melanin pigmentation is widely distributed in the skin and often in oral mucosa, but normally not existing in bone tissue. However, melanin pigmentation is detected on rare occasions with odontogenic lesions in the jaw bones, especially odontogenic keratocysts (OKC). Moreover, development of the tooth germ is originated from the neural crest, but elimination or expression of neural crest cells with odontogenic lesions is not obvious. The present study aimed to consider the origins of OKC based on the distribution of melanocytes in OKC. Findings One hundred and ten OKC were used. Eighty-eight cases showed sporadic type (SPO), and 22 cases involved basal cell nevus syndrome (BCNS). All samples were divided into 54 cases of juvenile group (0-29 years old) and 56 cases of advanced group (30-70 years old). Melanocytes were detected using Melan-A and HMB45 immunohistochemical stainings, and melanin pigmentation was detected using Schmorl's method. The positive rate of Schmorl's reaction, Melan-A and HMB45 staining were significantly higher in juvenile group than advanced group. These rates were also higher in BCNS than SPO. Conclusions Compare to juvenile and advanced groups, Melan-A and HMB45 positive rates were high in juvenile group. It is evident from these findings that the origin of OKC in juvenile group was different from advanced one. It means that the cyst epithelium in juvenile group originated from neural crest cell with melanocytes, and advanced one arose from odontogenic epithelium without melanocyte, for examples epithelial rest of Malassez.