Clinical Characteristics of Pars Tensa Cholesteatoma: A Comparative Study of Area-Based Classification Systems Proposed by the Japanese Otological Society and the European Academy of Otology - Neuro-Otology.

To assess the clinical characteristics of extent patterns in pars tensa cholesteatoma. This was a retrospective chart review. Forty-four patients with pars tensa cholesteatoma who underwent primary surgery at a tertiary academic medical center were included. The main outcomes measured were sex, age, clinical background, and stage classification of pars tensa cholesteatoma (including the extent of cholesteatoma and involvement of the sinus tympani) according to two staging classifications: criteria advocated by the Japanese Otological Society (JOS) and those advocated by the European Academy of Otology and Neuro-Otology (EAONO)/JOS joint consensus statements. The mean patient age ± standard deviation was 38.4±19.6 years. The patients comprised 19 men and 25 women. According to the JOS classification, 18 ears (40.9%) were classified as stage I, 22 (50.0%) as stage II, and 4 (9.1%) as stage III. According to the EAONO/JOS joint consensus statements, 14 ears (31.8%) were classified as stage I, 26 (59.1%) as stage II, and 4 (9.1%) as stage III. Fourteen ears (31.8%) demonstrated involvement of the sinus tympani. Four ears (9.1%) that were originally categorized as stage I cholesteatoma by the JOS criteria showed sinus tympani invasion and were subsequently categorized as stage II according to the EAONO/JOS criteria. We determined the clinical characteristics of pars tensa cholesteatoma based on the novel and well-defined classification criteria. Further studies including long-term outcomes are necessary to demonstrate the clinical relevance of the discrepancy between the two criteria with respect to involvement of the sinus tympani.