Comparative Evaluation of Mast Cells in Lichen Planus and Oral Lichenoid Reaction with Giemsa Staining

Introduction: Lichen planus is a relatively common and chronic mucocutaneous disease with unknown. Oral lichenoid reaction is clinical and histopathological similar to lichen planus, but the cause of it is different. Mast cells are responsible for the accumulation of inflammatory cells in the connective tissue. The aim of study was evaluation of the role of mast cells in pathogenesis of two groups of lesions. Methods: This cross-sectional study was performed on 26 samples of oral lichen planus, oral lichenoid reaction lesions and 5 samples of irritation fibroma. After the staining with the Giemsa, sections were observed under the optical microscope (x400), and the number of mast cells was counted. The results were analyzed using the SPSS16 software, T test, Mann- Whitney and Chi-squared statistical tests. Results: The total number of mast cells and degranulated mast cells in two groups were significantly higher than the control group (P<0/05). Nevertheless, the total number of mast cells, the number of degranulated mast cells and the ratio of degranulated mast cells to the total mast cells had no significant difference between the two groups of lesions. (P> 0/05). Conclusion: Mast cells play a role in the pathogenesis of lichen planus and lichenoid reaction lesions. The number of degranulated mast cells and the ratio of degranulated to the total mast cells cannot help to differentiate these two groups of lesions. Clinical examinations and proper history and attention to their etiologic factors have a significant role in differentiating them.