Intracanalicular facial nerve schwannoma.

OBJECTIVE

To investigate the capability of preoperative evaluations in predicting the precise anatomic origin of intracanalicular tumors.

STUDY DESIGN

We conducted a retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

A total of 11 patients (8 men and 3 women, 26-70 years old) with intracanalicular tumors who were treated surgically were included.

INTERVENTIONS

Pure-tone average, auditory brainstem response, caloric test, and temporal magnetic resonance imaging were done in all 11 patients. Electroneuronography has only been performed since 2003, and only 3 patients were evaluated.

MAIN OUTCOME MEASURE

Preoperative symptoms, pure-tone average, auditory brainstem response, caloric test, electroneuronography, and magnetic resonance imaging were compared between patients with facial nerve schwannomas and patients with vestibular schwannomas.

RESULTS

Postoperatively, facial nerve schwannomas were diagnosed pathologically in 2 (18%) of 11 patients. There were not any clues suggesting facial nerve schwannoma in preoperative evaluations.

CONCLUSION

A facial nerve schwannoma may be misdiagnosed as a vestibular schwannoma, especially when the tumor is confined to the internal auditory canal. There are no useful preoperative evaluation tools in predicting the precise nerve origin of intracanalicular tumors. These emphasize the need to fully inform the patient preoperatively.