*Corresponding author:Irit Allon, Department of Oral Pathology and Oral Medicine, School of Dental Medicine, Tel Aviv University, Tel Aviv 69978, Israel
Received: July 06, 2018; Published: July 16, 2018
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Aim: Oral melanotic macule is a well-circumscribed pigmented lesion that commonly occurs in the oral mucosa. Histologically, it is characterized by increased production of melanin by basal melanocytes which present normal number and normal morphologic features. Lesions may also exhibit melanin - laden macrophages in the adjacent lamina propria. Because of the benign histological appearance, most authorities ignore its pathogenesis. The purpose of the present study was to immunomorphologically characterize oral melanotic macules.
Materials and Methods: Cases of oral melanotic macule were included and compared with normal appearing margins of the lesion and as reactive hyperplastic lesions as controls. The morphological assessment was carried out by measurement of rete ridge lengths and by immunomorphometric analysis of the epithelial expressions of S100 and HMB45.
Results: The maximal epithelial width of oral melanotic macules was significantly higher than that of the controls. In addition, the frequency of expression of S100 and HMB 45 in OMM differed significantly from the controls; S100 was increased, and HMB45 was decreased.
Conclusion: We suggest that lesions in the spectrum of oral melanotic macule may represent the oral counterpart of skin lentigo, which is characterized by elongation of rete pegs. Higher number of S100 positive cells and low expression of HMB45 suggest an increased number of melanocytes with which lack melanogenic activity.
Keywords: Oral Melanotic Macule; S100; HMB45; Rete Ridge; Lentigo; Neural Crest; Epithelium; Subepithelial Connective Tissue; Wilcoxon Paired; Melanin Incontinence.