A comparative study of odontogenic keratocyst and orthokeratinized odontogenic cyst using Ki67 and α smooth muscle actin.

Aim: This study aimed to demonstrate and evaluate the expression of stromal myofibroblasts (MFs) and epithelial cell proliferation using α-smooth muscle actin (α-SMA) and Ki67 markers, respectively, in odontogenic keratocyst (OKC) and orthokeratinized odontogenic cyst (OOC) to correlate their aggressive behavior.

Materials And Methods: Twenty cases of OKC and twenty cases of OOC were stained with α-SMA and Ki67 markers for demonstration of stromal MFs and epithelial cell proliferation, respectively, and ten cases of well-differentiated squamous cell carcinoma were used as positive control. Assessment of the number of α-SMA-positive stromal cells and Ki67-positive epithelial cells determined by MFs and proliferative epithelial cell frequency in 10 high-power fields (×400) was presented as the mean number of positive cells per field.

Statistical Analysis: Kruskal-Wallis and Mann-Whitney test were used to analyze the difference in the mean number of α-SMA- and Ki67-positive cells per field between OKC and OOC.

Results: The mean number of positively stained cells for α-SMA and Ki67 is significantly higher in OKC compared to OOC.

Conclusion: Impression is that, the different behaviors of these two entities are compatible with their immunohistochemical view. The high value of stromal MFs and proliferative epithelial cells in OKC in comparison to OOC indicates its aggressiveness and potential for recurrence.