FACIAL NEUROMA OF THE CEREBELLOPONTINE ANGLE AND THE INTERNAL AUDITORY-CANAL

Four cases of facial neuroma confined to the cerebellopontine angle an d internal auditory canal are presented. Prior to surgery, three of th ese were diagnosed as an acoustic tumor. At operation the true diagnos is of facial neuroma was made. The operative procedure was recorded on film and videotape. The magnetic resonance imaging (MRI) and computed tomography (CT) scans were reviewed retrospectively. In the first thr ee cases the tumor was not centered on the axis of the internal audito ry canal (IAC), as would be typical of an acoustic neuroma, but instea d occupied a position eccentric to this axis. In one case, this eccent ricity was marked. A similar appearance in the fourth case enabled the true diagnosis of facial neuroma to be made before surgery. The posto perative behavior of the tumors was unpredictable. The patient with th e largest tumor, which was debulked at operation, did not develop a fa cial palsy. However, a patient with a small tumor which was not biopsi ed, developed a delayed but complete paralysis from which she subseque ntly recovered. This small series suggests that it may be possible, by use of the appropriate imaging technique, to diagnose, preoperatively , a cerebellopontine angle facial neuroma which is otherwise indisting uishable from an acoustic neuroma.