Normal specimens of lip mucosa taken from 195 surgical materials were examined histopathologically and immunohistochemically to determine mucosal melanocyte incidence and distribution with special references to aging process and sex differences. When all specimens were divided into four age groups (0-19 years, 20-39 years, 40-59 years, and 60-85 years), age-related significant increases of mucosal melanocytes were observed both in males and females, respectively (p<0.01). Especially, the number of mucosal melanocytes in over 60-year old males showed a more remarkable increase than that of other age groups. In addition, significant sex differences were found in each age group (male: 12.09±0.94/ 0.005 mm2, female: 4.11±0.36/0/005 mm2, p<0.001). These results indicate that melanocyte increases observed in the aged may play an important role as a precursor lesion for oral pigmented diseases such as senile lentigo and intraepithelial malignant melanoma.
