Cochlear schwannomas.

Schwannomas arising solely from the cochlear nerve and limited to the internal auditory canal are rare. Only three prior cases have been specifically described in the literature. We report a 38-year-old male with and asymmetric audiogram and poor discrimination. Magnetic resonance imaging revealed a 3-mm mass occupying the inferior portion of the internal auditory canal. Discrimination improved following a course of steroids, but thresholds did not. The patient underwent a translabyrinthine removal of the tumor, which was confirmed to involve only the cochlear nerve. It is important to obtain evidence regarding the possibility that a tumor confined to the internal auditory canal is a cochlear schwannoma. If so, surgery can be deferred until hearing is no longer functional or tumor growth mandates removal.