Melanocytes in odontogenic lesions

Melanocytes are widely distributed in the skin and often present in oral mucosa, but they do not normally exist in bone tissue. Previous reports have shown that melanin pigmentation was seen in some odontogenic lesions of the jaw bone. In this study, the presence of melanin pigmentation and melanocytes was analyzed in ameloblastomas, odontogenic keratocysts (OKCs), and radicular cysts. The aim of this study was to compare the existence of melanin pigmentation and melanocytes in ameloblastomas, radicular cysts, and OKCs, and to clarify the different origins of these odontogenic lesions. Melanin pigmentation was detected using hematoxylin and eosin (HE) staining and Schmorl’s method staining. The presence of melanocytes was confirmed with Melan-A immunohistochemical staining. Melanin pigmentation and melanocytes were shown in OKCs, only melanocytes appeared in ameloblastomas, and neither melanin pigmentation nor melanocytes were present in radicular cysts. Comparing younger and older cases of OKC, both Melan-A and Schmorl’s reaction-positive rates were higher in the younger cases. In conclusion, these data raise the important possibility that the origin of OKC epithelium differs from that of ameloblastoma and radicular cyst based on the expression of melanin pigmentation and melanocytes. These findings also underscore the fact that the origin of OKC differs between younger and older patients. It is suggested that melanin pigmentation and melanocyte expression may assist in the classification of OKCs and may be useful in the development of new therapies in the future.