Facial nerve schwannoma in the cerebellopontine cistern. Findings on high resolution CT and MR cisternography

Primary tumors of the facial nerve misdiagnosed: a case series and review of the literature

CONCLUSION

Unusual primary tumors of the facial nerve should be considered in patients with progressive facial paralysis, especially if this is accompanied by hearing loss or vertigo. Misdiagnosis could increase the difficulties of operation, diminish the chance of facial nerve reconstruction, and increase the likelihood of poor reconstructive outcomes.

OBJECTIVE

This paper was to determine the characteristics of facial nerve primary tumors misdiagnosed as tumor-free conditions many years prior, and to describe appropriate treatments.

METHODS

The cases of 11 Chinese patients with misdiagnosed primary tumors of the facial nerve were reviewed; every one had been misdiagnosed for more than 8 years. All patients presented with progressive or complete facial paralysis and hearing loss, with or without vertigo. The pre- and post-operative images (including CT scans of the temporal bone) and MRI data were reviewed.

RESULTS

All tumors were completely resected using the translabyrinthine or transmastoid approach and were confirmed to be primary tumors of the facial nerve. Facial-hypoglossal nerve anastomosis failed because fibrosis developed at the end of the facial nerve in one patient whom this study sought to manage in two stages. One patient accepted facial-hypoglossal nerve anastomosis of two-stage and patient status improved to House-Brackmann (H-B) grade V from H-B grade VI. The other nine patients chose not to undergo reconstruction.

Vestibular-like facial nerve schwannoma

OBJECTIVE

To evaluate the prevalence as well as the management of primary facial nerve schwannoma (PFNS) presenting as vestibular schwannoma.

METHODS

A retrospective review was carried out on 146 patients referred to and operated upon in our institution over a 5-year period for tumors of the internal auditory canal extending or not into the cerebello-pontine angle (TICA). A review of the literature included an extensive MEDLINE search of the literature since 1966 and careful inspection of the bibliography of each article. Articles pertaining to facial nerve schwannomas were reviewed to identify cases of vestibular-like facial (V-LF) nerve schwannoma.

RESULTS

Two cases of tumors were finally diagnosed as PFNS. Clinical and radiological evaluations were typical of a vestibular schwannoma. Facial function was normal in each case. Unsuspected facial nerve schwannomas were found during surgery. Tumor removal was not performed. Postoperatively House and Brackmann (HB) facial function was normal in one case and grade II in the other case. These two cases represented a 1.4% prevalence, which is within the limits reported in the literature. Among V-LF nerve schwannomas reported in the literature, the postoperative functional facial outcome usually worsened when the tumor was resected.

CONCLUSION

The prevalence of V-LF nerve schwannoma has been reported in the two last decades owing to the development of modern imaging. The conservative management of early staged tumors presenting as vestibular schwannoma is recommended in order to counsel the patient regarding the possibility of V-LF nerve schwannoma and to prolong normal facial function.

Fascicle preservation surgery for facial nerve neuromas involving the posterior cranial fossa

OBJECTIVE

To assess facial nerve function after fascicle preservation surgery in cases of facial nerve neuroma involving the cerebellopontine angle.

STUDY DESIGN

Retrospective case series and literature review.

SETTING

Tertiary referral center.

PATIENTS

Seven patients with facial nerve neuroma involving the posterior cranial fossa were reviewed from a single neurotologist's practice and combined with a review of 648 cases reported in the literature.

INTERVENTIONS

Translabyrinthine resection was used in all patients for complete tumor removal. Nerve reconstruction was accomplished with fascicle preservation (three cases), cable nerve interposition grafting (three cases, one of which involved using cranial nerve VIII as the graft), or direct anastomosis (one case).

MAIN OUTCOME MEASURE

Facial nerve function as measured by the House-Brackmann grading system. RESULTS A postoperative facial nerve (House-Brackmann) grade of II/VI was obtained in two of our three patients who underwent fascicle preservation reconstruction and in two of eight cases reported by other authors. One case reported elsewhere resulted in grade I/VI, and four other cases reported elsewhere achieved grade III/VI; only two cases were grade V/VI. There were no tumor recurrences at 5 to 19 years of follow-up.

CONCLUSION

Most cases of facial nerve neuroma require facial nerve resection. In rare cases, these tumors can be dissected away from the nerve fascicles, allowing the surgeon to preserve the facial nerve. This method resulted in better long-term postoperative facial nerve function (House-Brackmann grade II/VI vs. grade III/VI) compared with other techniques for patients in this small series, and no tumor recurrence.