A 11-year-old male presented with a hearing loss in the right ear and right facial palsy. Examination by CT and MRI showed a large acoustic neuroma which extended into the middle ear. The posterior quadrant of his right tympanic membrane was expanded due to the tumor. The tumor was surgically removed in a two staged operation, and the first operation was perfomed using the trans-labyrinthine approach and the second operation was done using the posterior cranial fossa approach. Even though the tumor had substantially destroyed the pyramis and extended into the inner and middle ear, the osseous labyrinth was still preserved. It is unusual that an acoustic neuroma was originated either in the inner ear or middle ear. We therefore postulated that the tumor might be originated in the internal auditory canal and thereafter expanded into the middle ear from the petrous cells and the inner ear windows.
