Immunohistochemical detection and ultrastructure of myofibroblasts in the stroma of odontogenic cysts and ameloblastoma

Abstract EN

Background : Immunohistochemical phenotype, distribution and significance of proliferation of my fibroblasts (α SMA positive cells) with evaluation of ultrastructure, in dentigerous cyst, odontogenic keratosis and ameloblastoma were analyzed.

Methods : the study included paraffin embedded blocks of ameloblastoma (n = 22), odontogenic keratosis (n = 20), and dentigerous cyst (n = 18).

The expression of α SMA was determined by immunohistochemically stained section.

The percentage of positive cells was calculated from a minimum of 1000 cells and H-score was expressed (% positive cells × intensity of staining).

For transmission electron microscopy, fresh specimens were obtained from three patients and were fixed in 2.5 % glutaraldehyde.

The presence of cells with the ultra-structural characteristics of the my fibroblast was recorded.

Results : the mean number of positive cells in the three groups was significantly different.

The difference between odontogenic keratosis and dentigerous cyst and also the difference between dentigerous cyst and ameloblastoma were not statistically significant.

The mean number of positive cells in the odontogenic keratosis was significantly higher than that in ameloblastoma.

In ultra-structural evaluation, my fibroblasts exhibited abundant cytoplasmic microfilaments, basal lamina-like material, subsurface coevolve, pinocytic vesicles, rough endoplasmic reticulum, and mitochondria's.

Conclusions : the high frequency of stromal my fibroblast in the odontogenic keratosis implies that my fibroblast can contribute to aggressive nature of this cyst, but between odontogenic cysts and ameloblastoma, the presence of stromal my fibroblast has no correlation with invasiveness.