Objective To expore the roles of cyclooxygenase-2 (COX-2) and phosphatase and tensin homology deleted on chromosome ten (PTEN) in the pathogenesis of middle ear cholesteatoma via detecting the expressions and correlation of COX-2 and PTEN.Methods Specimens of middle ear cholesteatoma (n=35), middle ear granuloma (n=20) and normal external auditory canal skin (control group, n=10) were obtained from the patients undergoing surgical treatment. The expressions of COX-2 and PTEN in the specimens were detected by immunohistochemical staining and western blotting, and the correlation between the expression of COX-2 and PTEN in middle ear cholesteatoma was explored by Person correlation analysis.Results The expression of COX-2 in the cholesteatoma group was significantly stronger than those in the granuloma group and the control group, while the expression of PTEN in the cholesteatoma group was significantly weaker than those in the granuloma group and the control group, and the differences were all statistically significant (P<0.05). Meanwhile, the expressions of COX-2 and PTEN in the cholesteatoma group had a significant negative correlation (P<0.05).Conclusion The increased expression of COX-2 and the decreased expression of PTEN are closely related to the incidence of cholesteatoma in the middle ear，which indicates that both COX-2 and PTEN may be involved in the occurrence and development of middle ear cholesteatoma through PI3K/Akt signaling pathway.