Quantitative Assessment of Stromal Myofibroblasts in Odontogenic Cysts: A Comparative Immunohistochemical Study

Myofibroblasts (MF) are fibroblasts having features like smooth muscle. Characteristic of this MF is the presence of a contractile apparatus. The transforming growth factor beta 1 (TGF-β1) has an important role in the conversion of fibroblasts in to MF and their maturation is due to platelet-derived growth factor. Some neoplastic epithelial cysts and tumors have a property to progress in to the aggressive lesion. Stromal MF is responsible for their aggressiveness and biological behavior. So, aim of the present study is to assess and compare immunohistochemically the frequency of stromal MF in different odontogenic cysts mainly Odontogenic keratocysts (OKC), Dentigerous cysts (DCs) and Radicular cysts (RCs). Immunohistochemical assessment of stromal MF was done on 45 cases, 15 cases of OKCs, DC, and RC, respectively. Frequency of MF was find out as a number of alpha smooth muscle actin (α-SMA) positive stromal cells in 10 high power fields. Cases of oral squamous cell carcinoma (OSCC, n = 5) was serve as a control. OKC had the highest mean number of α-SMA positive cells per field (26.8 ± 5.193) followed by DC (14.2 ± 3.493) while RC had the lowest cells (12.5 ± 3.155). The OSCC which used as a control showed the highest number of α-SMA positive cells per field (28.6 ± 3.050). The Present study showed that the stroma is not only responsible for the support and the maintenance of the epithelial tissue but also play a major role in the aggressive behavior of the lesion. OKC contains numerous MF in their stroma, which is similar with that found in cases of OSCC representative of its aggressive behavior and increased chances toward recurrence.