Intracranial and intratemporal facial neuroma

Current approaches to facial nerve schwannoma surgery

Background

Facial nerve schwannomas (FNSs) are exceedingly rare benign tumors. This study aims to report on a series of excised FNSs, providing clinical information and details on their surgical management, including novel approaches.

Methods

We retrospectively reviewed patients who underwent surgical excision of FNSs in a private otology clinic and public tertiary referral center. The main outcome measures were facial nerve function, complete tumor removal, postoperative complications, tumor recurrence, and hearing.

Results

Seventeen patients (10 men and 7 women) with a mean age of 44.23 years (SD, 12.21) underwent surgery during the study period. The most common symptom was facial nerve dysfunction (58.8%). Facial and otoneurologic symptoms (hearing loss, tinnitus, and vertigo) were observed in 88.8% and 77.7% of patients, respectively. The middle cranial fossa (MCF) was the most common approach (six patients, 35.2%), followed by translabyrinthine (TL), transmastoid (TM), and combined TM-MCF (three patients, 17.6% each). Exclusive endoscopic transcanal suprageniculate (ETS) and mastoid combined with cervical approaches were applied once in two patients, 5.8% each. Total tumor removal was achieved in all cases. No significant postoperative complications were observed. The mean follow-up period was 193.2 months (SD, 119.5) and no tumor recurrence was observed.

Conclusion

This study provides further evidence for the safety and efficacy of various surgical approaches for FNS, and incorporates the endoscopic transcanal approach.

Level of evidence

4.

Long-term follow-up results of facial nerve schwannoma with good facial nerve function: a multicenter study

PURPOSE

Facial nerve schwannomas (FNSs) are rare intracranial tumors, and the optimal management of these tumors remains unclear. We investigated the long-term follow-up results of FNS with good facial nerve function.

METHODS

At nine medical centers in the Korean Facial Nerve Study Group, 43 patients undergoing observation periods longer than 12 months for FNS with good facial nerve function (House-Brackmann grade ≤ II) were enrolled, and clinical and radiographic data were obtained for these cases.

RESULTS

The mean follow-up period was 63 months. In the majority of cases, tumors involved multiple segments (81.4%) and only eight cases were confined to a single site. There were no cases where the tumor was confined to the extratemporal region. Tumor size increased slightly, with an average estimated change of 0.48 mm/year. Twenty (46.5%) of 43 patients showed no change in tumor size. Seven patients (16.3%) showed worsening House-Brackmann (H-B) grade, of which two patients deteriorated from H-B grade I to II, four worsened to grade III, and one deteriorated to grade IV. The remaining 36 patients (83.7%) showed no change in facial nerve function. There was no difference in H-B grade according to tumor size at the time of diagnosis or change in tumor size.

CONCLUSION

We conducted a large-scale observational study of FNS with good facial nerve function. Our study showed that many patients maintained facial nerve function during long-term follow-up. Conservative management with regular examination and imaging can be an appropriate option for managing FNS with good facial nerve function.

Facial nerve schwannoma: Case report and brief review of the literature

Schwannomas are rare nerve sheath tumors that can occur throughout the body, and are symptomatic based on location, size, and impingement on adjacent structures. These tumors are often benign lesions and occur sporadically or from genetic conditions such as neurofibromatosis. Schwannomas may arise from peripheral nerves, gastrointestinal nerves, spinal nerve roots and cranial nerves. Facial nerve schwannomas arise from cranial nerve VII, commonly involving the geniculate ganglion, labyrinthine segment, and internal auditory canal. While small lesions are asymptomatic, larger lesions can cause facial nerve paralysis, and facial spasms. Lesions in the internal auditory canal can cause hearing loss, tinnitus, vertigo, and otalgia. High-resolution CT imaging and MRI imaging are useful for distinguishing between other pathologies that arise from the same region. High-resolution CT scans can show bony degeneration of nearby structures such as the labyrinth or ossicles. MRI imaging shows hypo intensity on T1 imaging, and hyperintensity on T2 imaging. On T1 postcontrast, enhancement can be homogenous or heterogeneous with cystic degeneration if the lesion is large. Nodular enhancement is commonly seen on facial nerve schwannomas within the internal auditory canal. Vestibular schwannomas involving CN VIII are more common, and appear similar to facial nerve schwannomas, but can be distinguished apart due to growth in the geniculate ganglion and/or the labyrinthine segment. Management of asymptomatic or mild lesions is typically conservative with follow up imaging, and surgery for larger lesions. Here, we present a case of a facial nerve schwannoma in a 57-year-old woman.

Schwannomas of Brain and Spinal Cord

Schwannomas are benign tumors originating from the Schwann cells of cranial or spinal nerves. The most common cranial schwannomas originate from the eight cranial nervevestibular schwannomas (VS). VS account for 6-8% of all intracranial tumors, 25-33% of the tumors localized in the posterior cranial fossa, and 80-94% of the tumors in the cerebellopontine angle (CPA). Schwannomas of other cranial nerves/trigeminal, facial, and schwannomas of the lower cranial nerves/are much less frequent. According to the World Health Organization (WHO), intracranial and intraspinal schwannomas are classified as Grade I. Some VS are found incidentally, but most present with hearing loss (95%), tinnitus (63%), disequilibrium (61%), or headache (32%). The neurological symptoms of VSs are mainly due to compression on the surrounding structures, such as the cranial nerves and vessels, or the brainstem. The gold standard for the imaging diagnosis of VS is MRI scan. The optimal management of VSs remains controversial. There are three main management options-conservative treatment or "watch-and-wait" policy, surgical treatment, and radiotherapy in all its variations. Currently, surgery of VS is not merely a life-saving procedure. The functional outcome of surgery and the quality of life become issues of major importance. The most appropriate surgical approach for each patient should be considered according to some criteria including indications, risk-benefit ratio, and prognosis of each patient. The approaches to the CPA and VS removal are generally divided in posterior and lateral. The retrosigmoid suboccipital approach is a safe and simple approach, and it is favored for VS surgery in most neurosurgical centers. Radiosurgery is becoming more and more available nowadays and is established as one of the main treatment modalities in VS management. Radiosurgery (SRS) is performed with either Gamma knife, Cyber knife, or linear accelerator. Larger tumors are being increasingly frequently managed with combined surgery and radiosurgery. The main goal of VS management is preservation of neurological function - facial nerve function, hearing, etc. The reported recurrence rate after microsurgical tumor removal is 0.5-5%. Postoperative follow-up imaging is essential to diagnose any recurrence.

Facial Nerve Schwannoma: The Rare/Great Mimicker of Vestibular Schwannoma/Neuroma

Schwannomas are benign tumors arising from Schwann cells which are a protective casing of nerves, composing myelin sheath and can develop in any nerve where Schwann cells are present. Most common are vestibulocochlear nerve schwannomas. Facial nerve schwannomas (FNSs) are uncommon tumors involving seventh nerve of which geniculate ganglion involvement is most common. Clinical presentations and the imaging appearances of FNSs are influenced by the topographical anatomy of the facial nerve and vary according to the segments involved. We report a case of 73-year-old man presenting with right side facial weakness of lower motor neuron type involvement. Computed tomography and magnetic resonance imaging are clinching the diagnosis. An early diagnosis is important in containing the disease facilitating early surgical intervention.

Peripheral facial nerve schwannoma at the inferior mandibular margin: a case report

Schwannomas commonly occur in the head and neck region as acoustic neuromas. Facial nerve schwannomas are rare and usually occur in the temporal region. A 57-year-old woman presented with a mass at the right mandibular margin. Magnetic resonance imaging revealed a schwannoma located immediately caudal to the mental foramen. We were initially uncertain whether it arose from the trigeminal nerve or the facial nerve. Excision was performed under general anesthesia. The mass was encapsulated and easily detached from the surrounding tissue. The nerve of origin was identified proximal to the tumor. A facial nerve origin was confirmed as the muscles supplied by the marginal mandibular branch of the facial nerve moved on nerve stimulation. Nerve fibers were not found distal to the tumor, possibly because they had been cut during excision. We believe that this is the first report of a schwannoma arising from the peripheral facial nerve.

Preoperative Differences in Intracranial Facial Versus Vestibular Schwannomas: A Four Nerve Assessment

OBJECTIVES

Assesses whether preoperative functional testing can distinguish vestibular schwannomas from facial nerve schwannomas medial to the labyrinthine segment.

STUDY DESIGN

Retrospective cohort.

METHODS

Retrospectively review surgically managed intracranial facial and vestibular schwannomas between January 2015 and December 2019 at two tertiary care centers. Patients with neurofibromatosis 2 and surgery for recurrence were excluded. Preoperative functional testing to include House-Brackmann scores, electroneuronography (ENoG), cervical vestibular evoked myogenic potentials (cVEMP), caloric testing, acoustic brainstem responses (ABRs), acoustic reflexes, and audiograms was compared between the two groups of schwannomas.

RESULTS

Twelve facial and 128 vestibular schwannomas met inclusion criteria. In only one case was a facial schwannoma diagnosed preoperatively from imaging. No statistically significant difference was found in preoperative House-Brackmann scores, ENoG, cVEMP, caloric testing, ABRs, or acoustic reflexes. Pure tone average was worse in the vestibular schwannoma group (63 dB [95% CI: 58-68 dB] vs. 46 dB [95% CI: 34-58 dB], P = .01), and the difference was more apparent in the lower frequencies. Word recognition score was better in the facial schwannoma group (66% [95% CI: 45-86%] vs. 41% [95% CI: 34-47%], P = .02).

CONCLUSION

Specialized preoperative functional evaluation of the nerves of the internal auditory canal cannot reliably predict the presence of an intracranial facial schwannoma. Hearing is better in facial schwannomas, particularly in the lower frequencies. This should raise the index of suspicion for an intracranial facial schwannoma, especially in candidates for hearing preservation vestibular schwannoma surgery.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:2098-2105, 2021.

Management of facial nerve schwannoma: when is the timing for surgery

PURPOSE

Although the estimated prevalence is extremely low, facial nerve schwannoma (FNS) is the most common primary tumor of the facial nerve (FN). In the present study, the outcome of surgical management in 18 patients with FNS was analyzed and an appropriate time for surgery was proposed.

MATERIALS AND METHODS

A total of 18 patients with FNS who underwent surgical management by a single surgeon from 1999 to 2018 were retrospectively analyzed.

RESULTS

Among the 18 patients, five had no facial paralysis before surgery. Near-total removal was performed in three cases, and two cases were managed with decompression. In 13 cases with various degree of preoperative facial palsy, nerve continuity was lost during surgery. FN was reconstructed using cable graft in ten cases, direct anastomosis in one case, and facial-hypoglossal nerve transfer in one case. Facial reanimation surgery without FN reconstruction was performed in one case due to a long-standing facial paralysis before surgery. Preoperative House-Brackmann (H-B) grade in all patients was significantly worse as tumor size increased. The correlation was not observed between the duration and severity of preoperative facial palsy. Analysis of 12 patients who underwent FN reconstruction revealed that all patients with good preoperative facial function (H-B grade II-III) recovered to H-B grade III after surgery (7/7, 100%). However, patients with poor preoperative facial function (H-B grade IV or worse) had only a 40% (2/5) chance of improving to grade III after surgery. Preoperative tumor size and duration of facial palsy did not affect postoperative final facial function.

CONCLUSION

We suggest that H-B grade III facial palsy is the best time for surgical intervention, regardless of the tumor size or duration of facial palsy.

Cerebellopontine angle schwannomas arising from the intermediate nerve: a scoping review

Intermediate nerve schwannomas (INS) are extremely rare lesions in literature. They have been described mimicking facial nerve schwannomas, but not vestibular schwannomas (VS). We aimed to review the previously published cases, as well as the evidence to believe that they are far more common, though usually misdiagnosed as facial or VS. We performed a review of PubMed/Medline and Embase of "intermediate nerve schwannoma," "facial nerve schwannoma," "greater superficial petrosal nerve schwannoma," "geniculate ganglion schwannoma," and "chorda tympani schwannoma" to identify all cases of INS, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. Furthermore, 2 cases operated at our center are shown to exemplify the proposed hypotheses. No article was excluded from review. Thirteen cases of INS, 11 cases of chorda tympani schwannoma, and 18 cases of greater superficial petrosal nerve schwannoma were found in literature. In facial nerve schwannomas, the predilection of schwannomas for sensory nerves, and the ability to preserve the motor facial nerve during tumor resection support the hypothesis of intermediate nerve as the nerve of origin. For VSs, the different arachnoidal arrangement of medial VS, the sharing of pia mater by the intermediate nerve and vestibular nerve, and the medial Obersteiner-Redlich zone of the intermediate nerve, support the hypothesis of intermediate nerve origin of some VS. The correct identification of the intermediate nerve as a nerve of origin of cerebellopontine angle schwannomas is of uttermost importance, especially when mistaken for VS, as this may account for the heterogeneity of facial and cochlear outcomes after surgery.

The Natural History of Facial Schwannomas: A Meta-Analysis of Case Series

Objective  This study is to establish predictors of facial paralysis and auditory morbidity secondary to facial schwannomas by assimilating individualized patient data from the literature. Design  A systematic review of the literature was conducted for studies regarding facial schwannomas. Studies were only included if they presented patient level data, House-Brackmann grades, and tumor location by facial nerve segment. Odds ratios (OR) were estimated using generalized linear mixed models. Main Outcome Measures  Facial weakness and hearing loss. Results  Data from 504 patients were collected from 32 studies. The geniculate ganglion was the most common facial nerve segment involved (39.3%). A greater number of facial nerve segments involved was positively associated with both facial weakness and hearing loss, whereas tumor diameter did not correlate with either morbidity. Intratemporal involvement was associated with higher odds of facial weakness (OR = 4.78, p  < 0.001), intradural involvement was negatively associated with facial weakness (OR = 0.56, p  = 0.004), and extratemporal involvement was not a predictor of facial weakness (OR = 0.68, p  = 0.27). The odds of hearing loss increased with more proximal location of the tumor (intradural: OR = 3.26, p  < 0.001; intratemporal: OR = 0.60, p  = 0.14; extratemporal: OR = 0.27, p  = 0.01). Conclusion  The most important factors associated with facial weakness and hearing loss are tumor location and the number of facial nerve segments involved. An understanding of the factors that contribute most heavily to the natural morbidity can help guide the appropriate timing and type of intervention in future cases of facial schwannoma.

Chances of Improvement in Cases of Vestibular Schwannoma Presenting with Facial Nerve Weakness: Presentation of Two Cases and Literature Review

Background and Study Aim  Facial nerve (FN) weakness as a presenting feature in vestibular schwannoma (VS) is extremely rare. We are presenting two different cases of VS with significant facial weakness and reviewed the literature for similar cases. Methods and Results  We are presenting two cases of VS with significant facial weakness. The first case was a 63-year-old male patient presented with 3 weeks' history of severe left-sided facial weakness (House-Brackmann [HB] grade V) and hearing loss. Magnetic resonance imaging (MRI) of the brain showed a tumor in the left internal auditory canal. Gross total removal with anatomical and physiological FN preservation was performed through a retrosigmoid approach under neurophysiological monitoring. FN function improved postoperatively to HB grade II after 16 months. The other case was 83-year-old male patient presented with sudden left-sided hearing loss and severe facial weakness (HB grade V). MRI of the brain 2.5 years before showed a left-sided (Class-T3A) cystic VS. The tumor was asymptomatic; wait-and-scan strategy was advised by the treating neurologist. Recent MRI of the brain showed approximately three times enlargement of the tumor with brain stem compression, extensive cystic changes, and suspected intratumoral hemorrhage. Surgery was performed; the tumor was subtotally removed through a retrosigmoid approach with intraoperative FN monitoring. The FN was anatomically preserved; however, physiological preservation was not possible. Severe facial weakness with incomplete lid closure persisted postoperatively. Conclusion  Surgical treatment could be offered to cases of suspected VS presenting with facial weakness, as these cases may still have a chance for improvement especially in laterally located tumors.

Intracanalicular vestibular schwannomas presenting with facial nerve paralysis

BACKGROUND

To describe the surgical management and postoperative course of two patients presenting with facial nerve (FN) paralysis as one of the presenting symptoms of small intracanalicular vestibular schwannomas (VS).

METHODS

Among 153 patients operated for VS since September 2010 to August 2017, two adult female patients presented with rapidly progressive hearing decrease, vestibular symptoms, and FN paralysis (House-Brackmann grades III and IV, respectively). In both cases, c.e. T1-weighted magnetic resonance imaging revealed an enhancing tumor within the internal auditory canal without lateral extension beyond the fundus.

RESULTS

Retrosigmoid approach and excision of tumor showed that the origin of tumor was from the superior vestibular nerve, extrinsic to FN. Gross total tumor resection was obtained, with FN preservation. In the first case, a millimetric fragment of capsule was left because of tight adhesion on FN itself. Histopathology confirmed schwannoma. After surgery, both patients improved FN motor function.

CONCLUSIONS

Although very rarely, VS may start clinically with FN palsy, mimicking FN schwannomas and other less common pathologies. This presentation is exceptional in patients with small intracanalicular VS. Early surgical resection is the only reliable treatment for decompression of nerve, avoiding a complete and not-reversible damage, with possible postoperative FN function improvement or complete recovery.

Facial nerve neuroma in the geniculate ganglion extending into the internal auditory canal: A case report

Facial nerve schwannoma is a very rare benign tumor representing less than 1% of intrapetrous lesions. Our patient is a forty-one year old female who has suffered from recurrent right facial palsy for the last six years. She was first misdiagnosed as having Bell's palsy and received corticosteroids which resulted in little improvement. She then had facial nerve decompression surgery which resulted in a partial improvement. Since then, she has suffered from recurrent attacks of facial palsy. Two years ago, she came to our hospital seeking further treatment options. The final diagnosis made by MRI was a possible facial nerve tumor. To obtain a better facial outcome, total tumor removal was performed through the middle cranial fossa approach along with facial-hypoglossal nerve end-to-side anastomosis through transmastoid approach. Her hearing was preserved, and she obtained a better facial outcome than that of her preoperative level. In conclusion, facial nerve schwannoma has the potential to be misdiagnosed as Bell's palsy which might lead to a delay in diagnosis, and end-to-side neurorrhaphy may be an effective alternative in a selected case.

A retrospective study on facial nerve schwannomas: a disease with a high risk of misdiagnosis and hearing loss

The objective is to increase awareness of facial nerve schwannomas (FNSs). Clinical data from 32 cases with FNSs who received surgical treatment from 2005 to 2015 were reviewed retrospectively. The clinical data included age, sex, presentations, duration, facial nerve function, temporal-bone high-resolution computed tomography (CT) and magnetic resonance imaging (MRI) findings, surgical approaches, and postoperative histopathological examination. 16 men and 16 women were included, aged 7-69 years. The average age at diagnosis was approximately 44 years. The mean duration of disease was 65 months, and the mean tumor diameter was 22.4 mm. A tendency of multisegment involvement was observed in 29 FNS cases. Geniculate ganglion and tympanic segments were the most commonly involved segments. Meanwhile, the incidence of misdiagnosis of this disease was 50%. We observed that when FNSs involved the proximal portion of genicular ganglion, the hearing function tended to be worse than when the FNSs only involved the genicular ganglion and/or its distal portion (p < 0.05); in such cases, the hearing loss tended to become more severe with a longer duration of the disorder (p < 0.05). Multiple segment involvement is common in patients with FNS. We need to be more aware of the hearing function when FNSs involve the proximal portion of genicular ganglion. Misdiagnoses of FNS are common, and patients can be misdiagnosed with Bell's palsy, otitis media, or other diseases. Image studies should be conducted for differential diagnosis. Once the decision to perform surgical resection was made, reconstruction of the facial nerve should be considered.

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.

Fractionated Stereotactic Radiotherapy for Facial Nerve Schwannomas

Purpose Data on the clinical course of irradiated facial nerve schwannomas (FNS) are lacking. We evaluated fractionated stereotactic radiotherapy (FSRT) for FNS. Methods Eight consecutive patients with FNS treated at our institution between 1998 and 2011 were included. Patients were treated with FSRT to a median dose of 50.4 Gy (range: 46.8-54 Gy) in 1.8 or 2.0 Gy fractions. We report the radiographic response, symptom control, and toxicity associated with FSRT for FNS. Results The median follow-up time was 43 months (range: 10-75 months). All patients presented with symptoms including pain, tinnitus, facial asymmetry, diplopia, and hearing loss. The median tumor volume was 1.57 cc. On the most recent follow-up imaging, five patients were noted to have stable tumor size; three patients had a net reduction in tumor volume. Additionally, six patients had improvement in clinical symptoms, one patient had stable clinical findings, and one patient had worsened House-Brackmann grade due to cystic degeneration. Conclusion FSRT treatment of FNS results in excellent control of growth and symptoms with a small rate of radiation toxicity. Given the importance of maintaining facial nerve function, FSRT could be considered as a primary management modality for enlarging or symptomatic FNS.

Facial nerve schwannomas presenting as occluding external auditory canal masses: a therapeutic dilemma

OBJECTIVE

To present a series of patients with facial nerve schwannomas (FNSs) presenting as occluding external auditory canal (EAC) masses.

STUDY DESIGN

Retrospective case series.

PATIENTS

Four patients were identified with mastoid segment FNSs occluding the EAC. Three patients presented with conductive hearing loss (CHL), and the fourth presented with facial paralysis, later developing CHL.

INTERVENTION

One patient underwent conservative debulking, removing the EAC component only. Two patients were managed nonoperatively with periodic cleaning of entrapped keratin. The fourth patient received radiation therapy.

MAIN OUTCOME MEASURES

Facial nerve function, canal cholesteatoma formation, and hearing.

RESULTS

Among the patients managed with serial cleaning of entrapped keratin, one maintained normal facial function and one worsened to House-Brackmann II/VI. Facial function worsened to House-Brackmann II/VI in the patient who underwent surgical debulking. The fourth patient, who received radiation, developed complete facial paralysis. All patients accumulated keratin medial to the tumor, and all had CHL.

CONCLUSION

When evaluating an EAC tumor, it is important to obtain imaging before biopsy because biopsy of a schwannoma can result in paralysis. EAC occlusion by a schwannoma presents a challenging management issue, particularly when cholesteatoma forms between the tumor and the tympanic membrane. The primary goal is maintaining normal facial function as long as possible and avoiding secondary ear canal complications. The presence of canal occlusion limits the choice of stereotactic radiation because this leads to a month-long period of tumor swelling and cutaneous sloughing. Resection and grafting are indicated when substantial facial weakness or twitch develops.

Stereotactic radiosurgery for facial nerve schwannomas: meta-analysis and clinical review

OBJECTIVE

Although several small individual series on stereotactic radiosurgery (SRS) for facial nerve schwannomas (FNSs) have been published, we aim to systematically aggregate data from the literature as well as from our institution to better understand the safety and efficacy of SRS for FNS.

DATA SOURCES

PubMed English language search for keywords "facial nerve schwannoma" AND "radiation therapy" published from January 1995 to 2014. Data from our institution were also included in the analysis.

STUDY SELECTION

Minimum study inclusion criteria included tumor treatment outcomes yielding 10 studies in the literature. In addition, our institution's data on six patients were included.

DATA EXTRACTION

Data included radiation treatment type, radiation dose, tumor size, tumor control, tumor control definition, FN function, hearing outcome, and duration of follow-up.

DATA SYNTHESIS

In total, there were 45 patients with at least 2-year follow-up. Forty-two patients (93.3%) had tumor control. Of those patients with described growth/shrinkage definitions, 50.0% had no growth, 43.3% had shrinkage, and 6.7% had growth. Of those articles that included FN functional outcomes, 26 patients (66.6%) had stable FN function, 8 (20.5%) had improved function, and 5 (12.8%) had worsened FN function after treatment. In total, there were 30 patients whose hearing outcomes were discussed in the literature. Of those with serviceable hearing before SRS (n = 14), nine (64.3%) had stable hearing and five (36.7%) had worsened function after SRS. The mean posttreatment follow-up period was 42.1 months.

CONCLUSION

SRS seems to be effective at either stabilizing or shrinking FNS. However, significant morbidities of FN paralysis hearing loss do exist.

Vestibular schwannoma atypically invading temporal bone

Vestibular schwannoma (VS) usually present the widening of internal auditory canal (IAC), and these bony changes are typically limited to IAC, not extend to temporal bone. Temporal bone invasion by VS is extremely rare. We report 51-year-old man who revealed temporal bone destruction beyond IAC by unilateral VS. The bony destruction extended anteriorly to the carotid canal and inferiorly to the jugular foramen. On histopathologic examination, the tumor showed typical benign schwannoma and did not show any unusual vascularity or malignant feature. Facial nerve was severely compressed and distorted by tumor, which unevenly eroded temporal bone in surgical field. Vestibular schwannoma with atypical invasion of temporal bone can be successfully treated with combined translabyrinthine and lateral suboccipiral approach without facial nerve dysfunction. Early detection and careful dissection of facial nerve with intraoperative monitoring should be considered during operation due to severe adhesion and distortion of facial nerve by tumor and eroded temporal bone.

Surgical findings to differentiate between facial nerve schwannoma and vestibular schwannoma

Objectives

Facial nerve schwannomas may be misdiagnosed as vestibular schwannomas (VSs) if the tumor is confined to the internal auditory canal (IAC) without involvement the geniculated ganglion or labyrinthine segment of facial nerve. Because facial nerve schwannomas may be misdiagnosed as VSs, we investigated the differences between the two.

Methods

The study included 187 patients with a preoperative diagnosis of VS. Of these, six were diagnosed with facial nerve schwannomas during surgery. We reviewed the preoperative evaluations and surgical findings of facial nerve schwannomas mimicking VSs.

Results

No useful preoperative predictors are available for facial nerve schwannomas mimicking VSs. Facial nerve schwannomas are usually confined to the IAC. After opening the dura of the IAC, a facial nerve schwannoma can be diagnosed after identifying a normal-appearing nerve located lateral to the tumor. When this was the case, we performed facial nerve preservation surgery or decompression.

Conclusion

Facial nerve schwannomas can be differentiated from VSs by identifying specific findings during surgery.

Intracranial nonvestibular neurinomas: Young neurosurgeons' experience

BACKGROUND AND OBJECTIVES

Neurinoma arising from other than nonvestibular cranial nerves is less prevalent. Here we present our experiences regarding the clinical profile, investigations, microneurosurgical management, and the outcome of nonvestibular cranial nerve neurinomas.

MATERIALS AND METHODS

From January 2005 to December 2011, the recorded documents of operated nonvestibular intracranial neurinomas were retrospectively studied for clinical profile, investigations, microneurosurgical management, complications, follow-up, and outcomes.

RESULTS

The average follow-up was 24.5 months. Total number of cases was 30, with age ranging from 9 to 60 years. Sixteen cases were males and 14 were females. Nonvestibular cranial nerve schwannomas most commonly originated from trigeminal nerve followed by glossopharyngeal+/vagus nerve. There were three abducent nerve schwannomas that are very rare. There was no trochlear nerve schwannoma. Two glossopharyngeal+/vagus nerve schwannomas extended into the neck through jugular foramen and one extended into the upper cervical spinal canal. Involved nerve dysfunction was a common clinical feature except in trigeminal neurinomas where facial pain was a common feature. Aiming for no new neurodeficit, total resection of the tumor was done in 24 cases, and near-total resection or gross total resection or subtotal resection was done in 6 cases. Preoperative symptoms improved or disappeared in 25 cases. New persistent deficit occurred in 3 cases. Two patients died postoperatively. There was no recurrence of tumor till the last follow-up.

CONCLUSION

Nonvestibular schwannomas are far less common, but curable benign lesions. Surgical approach to the skull base and craniovertebral junction is a often complex and lengthy procedure associated with chances of significant morbidity. But early diagnosis, proper investigations, and evaluation, along with appropriate decision making and surgical planning with microsurgical techniques are the essential factors that can result in optimum outcome.

Facial neuroma masquerading as acoustic neuroma

Facial nerve neuromas are rare benign tumors that may be initially misdiagnosed as acoustic neuromas when situated near the auditory apparatus. We describe a patient with a large cystic tumor with associated trigeminal, facial, audiovestibular, and brainstem dysfunction, which was suspicious for acoustic neuroma on preoperative neuroimaging. Intraoperative investigation revealed a facial nerve neuroma located in the cerebellopontine angle and internal acoustic canal. Gross total resection of the tumor via retrosigmoid craniotomy was curative. Transection of the facial nerve necessitated facial reanimation 4 months later via hypoglossal-facial cross-anastomosis. Clinicians should recognize the natural history, diagnostic approach, and management of this unusual and mimetic lesion.

Intraoperatively diagnosed cerebellopontine angle facial nerve schwannoma: how to deal with it

OBJECTIVE

This study aimed to report our experience in the management of patients with intraoperatively diagnosed intracranial facial nerve schwannomas (FNSs) and propose a decision-making strategy.

METHODS

Twenty-three patients with FNS of the internal auditory canal and/or cerebellopontine angle operated on between 1992 and 2012 were identified.

RESULTS

Preoperatively, all cases have been radiographically diagnosed as vestibular schwannomas. Operative procedures consisted of total tumor resection with grafting in 43.4% of patients, near-total resection leaving behind the tumor capsule overlying the facial nerve in 21.7%, total tumor resection with preservation of anatomic continuity of the facial nerve in 13%, and subtotal resection in 4.3%. Four patients (17.4%) underwent bony decompression with no tumor removal.

CONCLUSION

Management of FNS diagnosed at surgery represents a significant clinical challenge. We considered total tumor resection with grafting when patients presented with preoperative facial nerve palsy (≥ grade III). Both subtotal and near-total tumor removal can be performed in patients with preoperative good facial function and/or large tumors with brainstem compression. Patients with small tumors who were selected for hearing preservation surgery can be considered for bony decompression. Fascicle preservation surgery may be an option when a clear cleavage plane between the tumor and the facial nerve is found.

[Facial nerve neurinomas]

INTRODUCTION

Evaluation of diagnostic, surgical technique, treatment results facial nerve neurinomas and its comparison with literature was the main purpose of this study.

METHOD AND MATERIALS

Seven cases of patients (2005-2011) with facial nerve schwannomas were included to retrospective analysis in the Department of Otolaryngology, Medical University of Warsaw. All patients were assessed with history of the disease, physical examination, hearing tests, computed tomography and/or magnetic resonance imaging, electronystagmography. Cases were observed in the direction of potential complications and recurrences.

RESULTS

Neurinoma of the facial nerve occurred in the vertical segment (n=2), facial nerve geniculum (n=1) and the internal auditory canal (n=4). The symptoms observed in patients were analyzed: facial nerve paresis (n=3), hearing loss (n=2), dizziness (n=1). Magnetic resonance imaging and computed tomography allowed to confirm the presence of the tumor and to assess its staging. Schwannoma of the facial nerve has been surgically removed using the middle fossa approach (n=5) and by antromastoidectomy (n=2). Anatomical continuity of the facial nerve was achieved in 3 cases. In the twelve months after surgery, facial nerve paresis was rated at level II-III° HB. There was no recurrence of the tumor in radiological observation.

CONCLUSION

Facial nerve neurinoma is a rare tumor. Currently surgical techniques allow in most cases, the radical removing of the lesion and reconstruction of the VII nerve function. The rate of recurrence is low. A tumor of the facial nerve should be considered in the differential diagnosis of nerve VII paresis.

Facial nerve schwannomas of the cerebellopontine angle: the mayo clinic experience

Background There is often controversy regarding the optimal management for patients with facial nerve schwannomas (FNSs) of the cerebellopontine angle (CPA). Methods The clinical and radiological outcomes in 14 patients with CPA FNS were retrospectively reviewed. Results Patients underwent resection with anatomic nerve preservation (n = 3), facial-hypoglossal nerve anastomosis (n = 4), gamma knife radiosurgery (GKS) (n = 6), or observation (n = 1). A total of 83% of tumors that underwent GKS were stable or decreased in size. No patient who underwent resection showed evidence of tumor recurrence; the tumor under observation remained unchanged with normal facial function at the time of the last follow-up. Facial function was decreased in 57%, stable in 14%, and improved in 29% of those who underwent microsurgery. A total of 67% of patients who underwent GKS had stable facial function. Serviceable hearing was maintained in 50% of patients in the GKS group and 67% of the tumor resection group. Mean and median follow-up was 48 and 43 months, respectively (range, 12 to 95 months). Conclusion Observation should be the primary management when encountered with FNS of the CPA in those with good neurologic function. Microsurgery or radiosurgery may be used in those with poor facial function or tumor progression.

Evolution in the management of facial nerve schwannoma

OBJECTIVE

To design a treatment algorithm based on experience with facial nerve schwannomas (FNS) over a 30-year period.

STUDY DESIGN

Retrospective chart review.

METHOD

Seventy-nine patients with facial nerve schwannomas seen from 1979 through 2009 at a tertiary referral private otologic practice were categorized by treatment modality. Interventions included surgical resection with grafting, bony decompression, observation, or stereotactic radiation. Outcome measures included House-Brackmann facial nerve grade before and after intervention as well as change in facial nerve grade, tumor size, involved segments of nerve, time to intervention.

RESULTS

Thirty-seven patients (46.8%) ultimately underwent surgical excision with grafting or primary anastomosis, 21 (26.6%) underwent bony decompression alone, 15 (19.0%) were managed with observation only, and 6 (7.6%) had stereotactic radiation. Through 1995, 85% of cases had surgical resection and none had observation only. Of the 52 patients seen after 1995, 27% had surgical resection and grafting, 33% had bony decompression, 29% were managed with observation alone, and 11% had radiotherapy. Facial nerve grade was maintained or improved over the follow-up period (mean time = 3.9 years) in 78.9% of the decompression group and 100% of the observation and radiation groups compared to 54.8% of the resection group (P ≤ .012).

CONCLUSIONS

Surgical resection and grafting, once widely accepted and practiced, has in many cases given way to observation, bony decompression, or stereotactic radiation. A wide armamentarium of options is available to the neurotologist treating facial nerve schwannomas with the ability to preserve facial function for a longer period of time.

Surgical Management of PICA Aneurysm and Incidental Facial Nerve Schwannoma: Case Report

We report a patient with a posterior inferior cerebellar artery (PICA) aneurysm and an incidental facial nerve schwannoma at the cerebellopontine angle (CPA). A 46-year-old woman presented with the sudden onset of a severe headache, nausea, and vomiting. She had no other abnormal neurological symptoms and signs. Computed tomography (CT) showed hemorrhage in the fourth ventricle. Cerebral angiography demonstrated an aneurysm arising from the tonsillomedullary segment of the left PICA. A facial nerve schwannoma was incidentally found as the aneurysm was being clipped. The aneurysm was clipped via a left transcondylar approach. Subsequently, the schwannoma (2 x 3 x 2 mm) was resected from the facial nerve fascicles, and the facial nerve was preserved. Postoperatively, the patient developed mild to moderate dysfunction of the facial nerve (House-Brackmann grade III [H-B III]) but her hearing was intact. Both a facial nerve schwannoma involving the CPA and an aneurysm involving the PICA can be managed through the transcondylar approach. An asymptomatic facial nerve schwannoma can be resected safely with minimal facial nerve dysfunction.

Neurinoma of the greater superficial petrosal nerve developed acute facial palsy: case report and review of the literature

The authors report on a patient with a greater superficial petrosal nerve neurinoma. The patient developed severe acute facial palsy and the palsy improved soon after removal of the tumor. We review of the literature and describe its rarity and surgical treatment with regard to other facial nerve neurinomas originating from the main trunk of the facial nerve.

Facial nerve schwannomas

A study of 26 patients with facial nerve schwannomas treated at the University Hospital of Zurich was done. The general clinical features are described, but particular emphasis is placed on tumor histologic findings, recovery of facial function after grafting, and the nature of intracranial facial nerve schwannomas Presenting symptoms are stratified by tumor location, with facial dysfunction being commonest with intracranial tumors, neurotologic symptoms being associated with intracranial tumors, and parotid masses being a feature of extratemporal tumors. We found no differences in tumor histology regardless of site of origin. Clinical, histologic, and radiologic evidence is reviewed, and from this evidence we conclude that intracranial facial nerve schwannomas may be particularly invasive acoustic schwannomas. Recovery of facial movement after grafting the facial nerve is not influenced by graft length or graft type. Prolonged preoperative facial dysfunction has a negative influence on recovery after grafting.

Facial nerve schwannoma of the cerebellopontine angle: a diagnostic challenge

Facial nerve schwannomas are rare lesions that may involve any segment of the facial nerve. Because of their rarity and the lack of a consistent clinical and radiological pattern, facial nerve schwannomas located at the cerebellopontine angle (CPA) and internal auditory canal (IAC) represent a diagnostic and therapeutic challenge for clinicians. In this report, a case of a CPA/IAC facial nerve schwannoma is presented. Contemporary diagnosis and management of this rare lesion are analyzed.

Intradural facial nerve schwannoma: diagnostic and therapeutic problems

OBJECTIVES

To define characteristics of intradural facial schwannoma (FS) and discuss management strategies.

METHOD

Retrospective review of clinical charts.

RESULTS

Six patients were diagnosed, based on surgical findings, as having intradural FS. None of the patients complained initially of facial weakness, but all showed severe disturbance of hearing function assessed on admission. FS was suspected in four of our six patients because of imaging findings or facial palsy caused by a small tumor. Total removal was performed in five cases followed by facial nerve reconstruction, and nearly total removal was performed in one case. Most patients recovered to Grade II or III palsy during the follow-up, and long-lasting palsy before surgery showed poor recovery.

CONCLUSION

Imaging findings such as tumor extension to the middle fossa and clinical findings such as facial palsy caused by a small tumor strongly suggest a diagnosis of FS. Facial function can be restored satisfactorily for most patients after appropriate surgery.

Cerebellopontine angle facial schwannoma relapsing towards middle cranial fossa

Facial nerve schwannomas involving posterior and middle fossas are quite rare. Here, we report an unusual case of cerebellopontine angle facial schwannoma that involved the middle cranial fossa, two years after the first operation. A 53-year-old woman presented with a 3-year history of a progressive left side hearing loss and 6-month history of a left facial spasm and palsy. Magnetic resonance imaging (MRI) revealed 4.5 cm diameter of left cerebellopontine angle and small middle fossa tumor. The tumor was subtotally removed via a suboccipital retrosigmoid approach. The tumor relapsed towards middle cranial fossa within a two-year period. By subtemporal approach with zygomatic arch osteotomy, the tumor was subtotally removed except that in the petrous bone involving the facial nerve. In both surgical procedures, intraoperative monitoring identified the facial nerve, resulting in preserved facial function. The tumor in the present case arose from broad segment of facial nerve encompassing cerebellopontine angle, meatus, geniculate/labyrinthine and possibly great petrosal nerve, in view of variable symptoms. Preservation of anatomic continuity of the facial nerve should be attempted, and the staged operation via retrosigmoid and middle fossa approaches using intraoperative facial monitoring, may result in preservation of the facial nerve.

Surgical treatment of patients with facial neuromas--a report of 26 consecutive operations

OBJECTIVE

To analyze surgical treatment and outcome in patients with facial neuromas at a tertiary referral hospital.

STUDY DESIGN

A chart review of 26 patients treated between 1971 and 2006, with questionnaire follow-up ranging from 2 to 19 years. All patients except one were operated with radical tumor removal approaches.

RESULTS

Approximately 54% of the patients presented with symptoms related to the VIIth cranial nerve (facial palsy and facial spasm), 58% with symptoms related to the VIIIth cranial nerve (hearing deficit, tinnitus, and vertigo), and 8% related to the Vth cranial nerve (facial pain and facial sensory deficit). Approximately 39% presented with no facial symptoms. Twenty-one patients received a facial nerve graft from the greater auricular nerve or the sural nerve; 1 patient had an accessory-facial anastomosis. One patient had a subtotal tumor removal preserving the facial nerve. Three patients were not grafted. Most tumors (88%) affect the geniculate ganglion. Approximately 82% of the grafted patients regained a House-Brackmann facial nerve function (HB) grade III; 14% regained HB grades IV to V. No serious morbidity or mortality was reported. No recurrences have been reported where a total tumor removal was performed.

CONCLUSION

Surgical removal of facial neuroma is a safe procedure with a low complication rate and a low recurrence rate. First symptoms are diverse and are predominantly derived from the facial and vestibulocochlear nerve. Facial nerve grafting is reliable, giving the patient an acceptable facial nerve function (HB III).

Gamma knife radiosurgery for facial schwannomas

OBJECTIVE

Patients who have a schwannoma of the facial nerve (facial schwannoma, facial neuroma) can be managed with observation, surgical resection, stereotactic radiosurgery, or fractionated radiotherapy. Attempted complete resection is associated with facial weakness. The role of radiosurgery in these patients remains to be defined.

METHODS

We reviewed the clinical and imaging outcomes in patients who underwent gamma knife radiosurgery for a facial schwannoma.

RESULTS

Six patients had radiosurgery and were followed for a mean and median of 46.6 and 61.5 months, respectively (21-85 months). Three had a previous resection, and in 3 the diagnosis was made based on clinical and imaging criteria. All patients had facial nerve symptoms (5 had weakness and 1 had muscle twitching). House-Brackmann grades before radiosurgery were as follows: 1 (n = 1), 2 (n = 3), 3 (n = 1), and 6 (n = 1). The radiosurgery margin dose was 12 or 12.5 Gy. On later imaging, 3 tumors had regressed (with the longest follow-up duration) and 3 were unchanged. All patients had preservation of their preradiosurgery facial function. No other adverse effects were noted and all patients maintained their preradiosurgery level of hearing.

CONCLUSION

Over a mean of almost 4 years of follow-up, radiosurgery was shown to be a safe and effective management for residual and newly diagnosed facial schwannomas.

Schwannoma of the intermediate nerve

The intermediate nerve is seldom identified as the site of tumor origin in cerebellopontine angle schwannomas. A 29-year-old man presented with a 6-month history of slowly progressive hearing loss and dizziness; facial nerve weakness was not observed clinically. Magnetic resonance imaging revealed a tumor in the left cerebellopontine angle region extending up to the geniculate ganglion and along the course of the superficial petrosal nerve. A CT scan showed enlargement of the facial nerve canal. Microsurgery was performed via an extended retrosigmoid approach. Intraoperative and electrophysiological findings identified the intermediate nerve as the site of tumor origin.

Facial schwannoma: results of a large case series and review

OBJECTIVES AND HYPOTHESIS

To report a series of 53 cases of facial schwannoma, to review the current literature, addressing contentious issues, and to present a management algorithm.

STUDY DESIGN

Retrospective case review combined with review of current literature.

MATERIALS AND METHODS

A review of the case notes of 53 patients with intracranial and intratemporal facial schwannoma, from two tertiary referral centres, was undertaken. This represents the largest series of facial schwannomas with clinical correlations in the literature. Data relating to epidemiological, clinical and management details were tabulated and compared with other large series. A review of the current literature was performed, and a management algorithm presented.

RESULTS

There were 23 (43 per cent) female and 30 (57 per cent) male patients. Patients' ages at presentation ranged from five to 84 years, with a mean of 49 years. Twenty-five (47 per cent) of the tumours were present on the left side and 28 (53 per cent) on the right side. Hearing loss was the most common presenting symptom, being present in 31/53 (58 per cent) patients, followed by facial weakness in 27/53 (51 per cent). Two patients (4 per cent) were completely asymptomatic, and their facial neuromas were diagnosed incidentally. The schwannoma extended along more than one segment of the facial nerve in 39 patients (74 per cent), with the mean number of segments involved being 2.5. A conservative approach of clinical observation was undertaken in 20 patients (38 per cent). Thirty-three patients (62 per cent) underwent surgery, with a total of 36 procedures. The translabyrinthine approach was most common, being utilised in 17 of the 36 procedures. Two patients underwent revision surgery for residual or recurrent disease on three occasions. There was total removal of tumour in 21 cases; the remainder had subtotal or no removal with drainage or decompression of the tumours. Twenty-one nerve reconstructions were performed, and 18 facial rehabilitation procedures were performed on 14 patients.

DISCUSSION

The results of this case series are similar to those of other reported series. The diagnosis of facial schwannoma is now generally made pre-operatively, due to improved imaging techniques and heightened awareness. Clinical assessment of facial function and imaging form the mainstays of surveillance for these tumours. These tumours are managed via clinical observation or surgical intervention; the latter can range from simple procedures (such as drainage of cystic components) to aggressive tumour removal and facial nerve reconstruction. Facial rehabilitation procedures may also be applied. The timing of intervention is contentious; surgical intervention is indicated when facial function deteriorates to a House-Brackmann grade IV level.

CONCLUSION

Facial schwannomas are rare lesions, and reported series are generally small. Due to the complex management issues involved, these tumours are best managed in a tertiary referral setting. Observation is preferred until facial function deteriorates to a House-Brackmann grade III level, at which time surgery is considered. When facial function deteriorates to House-Brackmann grade IV, surgical intervention is indicated. We advocate surgical management based on the treatment algorithm described.

Surgical Management of Facial Neuromas

OBJECTIVE

Primary tumors of the facial nerve are rare, representing 1% of all intrapetrous lesions. We analyzed the management and surgical outcomes of 16 patients with multisegment facial neuromas treated at our institution during a 16-year period.

STUDY DESIGN

A retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

All patients included in the study had surgical management of their facial neuroma. There were 9 women and 7 men. The mean age was 46 years, with a mean follow-up period of 3 years.

INTERVENTION

Surgical excision (n = 15) or decompression (n = 1) of facial neuroma.

MAIN OUTCOME MEASURES

Tumor location, presenting symptoms, hearing outcomes, and facial function.

RESULTS

Thirteen (81%) patients had facial paresis as their presenting symptom. Unilateral hearing loss was present in 9 (56%) patients. Most tumors (n = 15) involved multiple segments of the facial nerve and ranged in size from 1.5 to 7 cm. Fifteen (94%) patients had the tumor completely excised, and 1 (6%) patient underwent needle decompression of the cystic component of the tumor. The geniculate ganglion was the most commonly involved (11 patients, 69%) segment of the nerve, followed by the labyrinthine and tympanic segments. Despite multiple types of reconstructive options used, the best recovery of facial function was a House-Brackmann Grade III in 12 patients.

CONCLUSION

Treatment of facial neuromas depends on the extent of tumor, degree of facial paresis, and hearing function. We advocate complete resection of tumor when facial palsy exists. Patients with normal facial function and hearing may be advised on a more conservative treatment option such as radiologic observation, drainage of any cystic component of the tumor for histologic diagnosis, and/or bony decompression of the tumor.

Treatment of a Facial Nerve Neuroma with Fractionated Stereotactic Radiotherapy

BACKGROUND

Facial nerve neuromas are extremely rare and are often mistaken for acoustic neuromas when located near the vestibular nerve. Usually presenting with facial weakness and hearing loss, facial nerve neuromas of the cerebellopontine angle have commonly been managed by surgery. We present the first reported case of a facial nerve neuroma treated with fractionated stereotactic radiotherapy (FSRT).

METHODS

The patient was a 40-year-old woman who presented with tinnitus, dizziness and decreased hearing that was associated with a right intracanalicular mass on magnetic resonance imaging (MRI). She underwent a middle fossa craniotomy only to reveal a facial nerve tumor rather than an acoustic neuroma that was not resected due to the high risk of facial paralysis. Following surgery, her facial function worsened and was associated with tumor enlargement on MRI. She was referred for FSRT and received 54 Gy in daily 1.8-Gy fractions with a prescription isodose line of 90%.

RESULTS

Three months after treatment she had no worsening of her pretreatment symptoms, and at the 1-year follow-up, she experienced facial weakness improvement accompanied by an absence of tumor growth on MRI. These clinical and imaging findings persisted at 48 months of follow-up.

CONCLUSION

In the first report of a facial nerve neuroma treated with FSRT, this treatment resulted in excellent long-term (4-year) tumor control with improvement of pretreatment symptomatology and absence of morbidity. This report demonstrates the potential for using FSRT to treat facial nerve neuromas of the cerebellopontine angle that could otherwise be associated with significant operative morbidity.

Silent intratemporal facial nerve schwannoma associated with Chronic Suppurative Otitis Media: A rare presentation

Facial palsy is a common manifestation of intratemporal facial nerve schwannoma. Review of English literature describes intratemporal facial nerve schwannoma presenting as vertigo, tinnitus (without facial palsy) which were diagnosed on CT scan or MRI of temporal bone. We are presenting two cases of asymptomatic facial nerve schwannoma without facial palsy presenting only as Chronic Suppurative Otitis Media (CSOM), which were diagnosed incidentally during surgery.

[Intracranial facial nerve schwannomas. Seven cases reviewed]

BACKGROUND AND PURPOSE

Intracranial facial nerve schwannomas are rare neoplasms. Preoperative diagnosis is difficult because of non-specific clinical presentations (deafness, facial paralysis sudden or progressive) and radiological differential diagnosis (petrous bone tumor, vestibular schwannoma). Treatment depends on localization and has to be discussed for each case.

METHODS

Seven cases (four men and three women) of intracranial facial nerve schwannomas were retrospectively studied.

RESULTS

Before treatment, we found deafness in six cases (two sudden and four progressive), a facial palsy in five cases (three sudden and two progressive). Five patients had deafness and facial palsy. One patient had only headache. Three schwannomas were supra and intra-petrous, two in the cerebello-pontine angle, and two were plurifocal (petrous bone, internal auditive canal and cerebellopontine angle). Six patients were operated on with an oto-neurosurgical procedure. After treatment, facial palsy always worsened (requesting secondary hypoglosso-facial anastomosis in cinq cases). Only one case of transmission deafness improved after ossiculoplasty. One patient is still under clinical and radiological observation.

CONCLUSION

Diagnosis is difficult and made operatively in half of patients. A large tumor requires surgery, but surveillance can be a good option for a small one, considering the risk of postoperative facial palsy.

Radiosurgery for facial schwannoma

Object

The aim of this study was to evaluate the results of radiosurgery in patients with facial schwannoma.

Methods

The study population consisted of 14 patients, six men and eight women, with a mean age of 45.4 years. Most of the patients had presented with facial palsy (11 of 14 patients) and/or hearing disturbance (nine of 14 patients). Prior treatment in nine of the 14 cases consisted of tumor resection or tumor biopsy. Tumor volume ranged from 0.98 to 20.8 cm3, and the mean tumor volume was 5.5 cm3. The mean maximum radiation dose and mean tumor margin dose used for radiosurgery were 24.0 and 12.9 Gy, respectively.

During the mean follow-up period of 31.4 months (range 12–120 months), 10 of the tumors shrank and four remained unchanged. The tumor response and tumor control rates were 57 and 100%, respectively. None of the tumors progressed, and no subsequent resection was required. Facial nerve function improved in five cases, remained unchanged in eight, and became worse in one. There was no change in hearing function in any of the patients. Complications developed in only one patient: the onset of facial palsy immediately after treatment, which subsequently recovered to House–Brackmann Grade III.

Conclusions

In summary, radiosurgery was found to be a very useful method of treating facial schwannoma, for both tumor control and functional control. Radiosurgery should therefore be the treatment of first choice for facial schwannomas.