Staging and classification criteria for middle ear cholesteatoma proposed by the Japan Otological Society.

In order to provide a basis for meaningful exchange of information among those treating cholesteatoma, the Committee on Nomenclature of the Japan Otological Society (JOS) was appointed in 2004 to create a cholesteatoma staging system as simple as possible to use in clinical practice in Japan. Following the announcement of preliminary criteria for the staging of pars flaccida (attic) cholesteatoma in 2008, we proposed the 2010 JOS staging system for two major types of retraction pocket cholesteatoma, pars flaccida and pars tensa cholesteatoma. Since then, the JOS staging system has been widely used in clinical studies of cholesteatoma in Japan, allowing standardization in reporting of surgical outcomes based on the respective stages of cholesteatoma. We have recently expanded the range of cholesteatoma by adding cholesteatoma secondary to a tensa perforation and congenital cholesteatoma as the 2015 JOS staging system for middle ear cholesteatoma. Although further revisions may be required for universal acceptance of these criteria, we hope our staging system will open the way for international consensus on staging and classification of middle ear cholesteatoma in the near future.