Objective:Retrospctive analysed the Characteristics and outcomes of surgical treatment of 18 patients who were diagnosed as secondary acquired cholesteatoma (SAC).Method:Patients with SAC accepted operations were enrolled in this study. Then the factors such as sex, age, cource of history, otorrhea before operation, the size of perforation of tympanic membrane, entry site of epithelium, extension direction, ossicular destruction, tympanosclerosis, tympanum tympani tendon involvement, stage of cholesteatoma（JOS, 2015, Japan），degree of gasification of mastoid（JOS，2015，Japan），air conductive threshold, bone conductive threshold, air-bone gap, the healing of tympanic membrane and the auditory improvement were analyzed.Result:Eighteen patients were enrolled in this study, with course of history range from 2 months to 50 years (average: 20.20±16.31) years. There were 14 cases with wet ear before operation. All patients were conformed with perforation of membranal tensa by otoendoscopic photography before operation, with nearly total in 5 ears,large size in 10 ears,medium size in 2 ears and small size in 1 ear. Ossicular erosion were found in 13 patients (malleus involved in 6, incus involved in 12 and stapes involved in 4). Thirteen patients with tendon of tensor tympani involved and 9 patients with tympanosclerosis were conformed during operation. The epithelium entered through the malleus manubrium to the promontory in 13 cases, through the edge of the perforation in 3 cases and through the incus long process to around stapes in 1 case. Cholesteatoma invasion extend to anterosuperior area in 3 cases, posterosuperior area in 3 cases,both in anterosuperior and posterosuperior area in 12 cases. The cholesteatomas classified: stage Ⅰ in 11 cases, stage Ⅱ in 7 cases. Mastoid gasification classified MC0 in 6 cases, MC1 in 10 cases and MC2 in 2 cases. The average air conductive threshold was (56.32±10.15) dB, bone conductive threshold was (20.76±6.22) dB and air-bone gap (35.56±9.84) dB.Tympanic membrane healed in all patients during following up, without recurrent of cholesteatoma, and the post-operative air conductive threshold (43.02±14.96) dB and air-bone gap (21.04±12.90)dB were improved significantly(P<0.05).Conclusion:Most of SAC were secondary to nearly total or large perforation of membranal tensa (83.33%), with relative long history of chronic otitis media (average 20.20 ± 16.31) years and otorrhea before operation. The epithelium entered mainly through the malleus manubrium to the promontory，then through edge of the perforation，by extending anterosuperior and posterosuperior area and usually accompanied with tendon of tensor tympani involved, ossicular destruction, and poor mastoid gasification and tympanosclerosis. The characteristics of SAC were different from other type of cholesteatoma which need further researches.
Keywords: epithelium; otitis media; secondary acquired cholesteatoma.