Evaluation of Stromal Myofibroblast in Odontogenic Cysts and Ameloblastoma

Abstract:

Objective:Odontogenic lesions form important part of oral and maxillofacial pathology. Immunohistochemical phenotype, distribution and significant of proliferation of myofibroblasts (á SMA positive cells) with evaluation of ultrastructure, in Dentigerous cyst , odontogenic keratocyst and Ameloblastoma were analyzed. Myofibroblasts are fibroblasts with smooth muscle-like features characterized by the presence of a contractile apparatus.

Methods:This is discriptive prospective study included of 22 ameloblastoma (11 folicular and 11 plexiform), 20 OKC and 18 Dentigerous cyst. The expression of á SMA was determined by Streptavidin-Biotin Immunohistochemistry technique on paraffin embedded blockes. The percentage of positive cells was calculated from a minimum of 1000 cells and H-SCORE was expressed (% positive cells * intensity of staining). Electron microscopy was used to observe structure of myofibroblasts.

Results:Mean number of positive cells, between three groups were significantly different (PV=0.002). The difference between OKC and dentigerous cyst was not significant ( PV=0.164). comparision between dentigerous cyst and ameloblastoma was not statistically significant.( PV=0.344). Mean number of positive cells in OKC was significantly higher than in ameloblastoma ( PV<0.001). The inflammation did not effect on results. In ultrastructure myofibroblasts showed microfilaments, rough endoplasmic reticulum, basal lamina, and subsurface caveolae.

Conclusion:The high frequency of stromal myofibroblast in OKC implies that myofibroblast can contribute to aggressive nature of this cyst. But between odontogenic cysts and ameloblastoma, presence of stromal myofibroblast doesn't have correlation with invasiveness.