Evaluation of mast cells in odontogenic cysts by toluidine blue & c-kit gene product (CD117)

Introduction: Odontogenic cysts are characterized by an expansile non–infiltrative growth through several mechanisms which include presence of mast cells in the capsule. The mast cells can be demonstrated histochemically as well as immunohistochemically. Aim and Objectives: The primary objective of the study was to analyze the presence and distribution of mast cells in radicular cyst, dentigerous cyst and keratocystic odontogenic tumor histochemically and immunohistochemically, to intercompare their expression and to correlate it with the degree of inflammation. Material and Methods: Tissue sections of 30 cases each of radicular cyst, dentigerous cyst and keratocystic odontogenic tumor were stained with toluidine blue and CD117. Quantitation and localization of mast cells was determined by dividing the section into subepithelial and deep zone. The mean number of mast cells was compared between toluidine blue and CD117 for each cyst, and also between two zones for each cyst, using ANOVA test. Correlation of mast cells with degree of inflammation was done using Pearson's correlation coefficient. Results: The mean number of mast cells were maximum in keratocystic odontogenic tumor, both histochemically and immunohistochemically, with high localization in the subepithelial zone. Immunohistochemical staining detected higher number of mast cells than histochemistry (4.54 and 3.23 respectively). Statistically significant correlation of mast cells with degree of inflammation was observed. Conclusion: Mast cells may play a role in the pathogenesis of odontogenic cysts as an elevated number of mast cells were found in the connective tissue capsule of all three odontogenic cysts.