immunohistochemical expression of mast cell in oral reactive lesions

statement of the problem: soft tissue reactive lesions are the most common lesions of the oral cavity. although many studies have shown the interaction of mast cells with fibroblasts and their participation in fibrosis, the role of mast cells in these lesions is not well understood. purpose: the aim of this study was to evaluate the mast cells (mcs) count in oral soft-tissue reactive lesions including peripheral giant cell granuloma (pgcg), peripheral ossifying fibroma (pof), irritation fibroma (if) and normal oral mucosa. materials and method: in this cross-sectional study, 50 samples including if, pgcg, pof (14 cases for each group) and 8 cases of normal oral mucosa were stained with tryptase antibody through immunohistochemistry. the number of mast cells was counted in 5hpf containing maximum counts for each section stained with tryptase. statistical analysis including chi-square test and tukey test with a significance level of 0.05 were considered. results: the number of mcs was found to have increased in reactive lesions compared with normal oral mucosa. mcs count in the pof group was higher than the others.                                                                                       conclusion: these findings suggest a possible role of mast cells in the pathogenesis of reactive oral lesions and induction of fibrous tissues. chemical mediators released from mast cells might influence other cells, especially fibroblasts, to induce fibrosis.