Comparative Evaluation of the Presence of Connective Stroma Myofibroblasts and Mast Cells in Odontogenic Keratocyst, Odontogenic Myxoma and Adenomatoid Odontogenic Tumor

Odontogenic cysts and tumors are important jaw lesions. Sometimes their behavior is influenced by non-epithelial factors. Myofibroblasts are specific cells of the stroma. Mast cells affect the differentiation and function of myofibroblasts. Regarding the importance of stroma in the progression of tumors, the present study examined the presence of mast cells and myofibroblasts and their effects on odontogenickeratocyst (OKC), odontogenicmyxoma (OM) and adenomatoidodontogenic tumor (AOT). In this cross-sectional descriptive-analytical study, 10 blocks of OM, 7 blocks of OKC and 6 AOT blocks from the Archives of the Department of Pathology, Isfahan Dental School, were stained with αSMA immunohistochemistry marker and toluidine blue histochemical marker. The mean number of myofibroblasts and mast cells, the color pattern of myofibroblasts and the severity of inflammation of the lesions were evaluated. Data was analyzed by SPSS 20 using Kruskal-Wallis, Mann-Whitney and chi-squared tests (α = 0.05). The degree of myofibroblast staining was not significantly different between the lesions (p value = 0.55), but the severity of inflammation was significantly different (p value = 0.02). The severity of inflammation in OKC was significantly higher than AOT (p value = 0.025) and OM (p value = 0.023) but there was no significant difference between AOT and OM lesions (p value = 0.87). There was a significant difference between the distribution patterns of the lesions (p value = 0.015). The frequency of the focal pattern in the OKC was minimal. The number of intact (p value = 0.72), degranulated (p value = 0.69) and total (p value = 0.75) mast cells were not significantly different between the lesions. There were no significant differences in the number of mast cells and myofibroblasts between the lesions, but myofibrroblasts were expressed with higher levels in OM, which is more invasive.