Comparing Eosinophil Density in Dental Follicle, Follicular Cyst, and Keratocystic Odontogenic Tumor

Background and purpose: Keratocystic odontogenic tumor tends to recur and behave more aggressively than follicular cysts and dental follicles. Eosinophils are multifunctional leukocytes, but their role in oral lesions is controversial. Current study aimed at assessing the density of eosinophils in aggressive odontogenic lesions. Materials and methods: In this descriptive-analytical cross-sectional study, paraffin blocks were obtained from Babol Dental School archives including 16 cases of keratocyst,19 follicular cyst, and 12 dental follicle and their demographic characteristics were extracted. The overall density of eosinophils and density of eosinophils in adjacent areas and away from odontogenic epithelium were examined in slides stained with Congo red in 10 microscopic fields (40x). Results: Eosinophil density was 0.08±0.3 in dental follicles, 1.7±2.1 in follicular cysts, and 6.14±5.6 in keratocystic odontogenic tumors. The eosinophil density in areas adjacent to odontogenic epithelium in keratocyst and follicular cysts was greater than that in areas away from odontogenic epithelium (P>0.001). Conclusion: Based on current study, eosinophils appear to influence the pathogenesis of follicular cysts and keratocystic odontogenic tumors. Their increased density in keratocysts, especially in the vicinity of odontogenic epithelium, is effective in its aggressive behavior.