Intralabyrinthine schwannomas: a case series with discussion of the diagnosis and management

Surgical Outcomes of Simultaneous Cochlear Implantation and Intracochlear Schwannoma Removal

OBJECTIVE

Intracochlear schwannoma is very rare, and complete loss of hearing is inevitable after the removal of this tumor. Here, we discuss cochlear implantation (CI) performed simultaneously with the removal of an intracochlear schwannoma.

STUDY DESIGN

Retrospective single-center study.

SETTING

Tertiary medical institute.

METHODS

Simultaneous CI and intracochlear schwannoma removal were performed in 4 subjects. After subtotal cochleostomy, the tumors were removed meticulously, with preservation of the modiolus. A new slim modiolar electrode (Nucleus CI632) was placed in a manner that hugged the modiolus. The surgical outcomes of functional gain, word recognition score (WRS), sound localization, and hearing in noise and speech intelligibility tests were investigated.

RESULTS

Intracochlear schwannomas were removed successfully from the 4 patients, with no remnant tumor. The mean aided hearing threshold 6 months after surgery was 25.0 ± 1.8 dB, and the mean-aided WRS with a 60 dB stimulus was 36.0 ± 18.8% (range 16%-60%). The Categorical Auditory Performance (CAP) score of the 3 single-sided deafness patients under contralateral ear masking was 7. The CAP score of the patient with bilateral sensorineural hearing loss was 6, which improved from a preoperative score of 0.

CONCLUSION

When an intracochlear schwannoma does not completely invade the modiolus, CI with simultaneous tumor removal can be performed successfully, resulting in good hearing performance. A slim modiolar electrode can be placed stably at the modiolus after schwannoma removal.

Full Endoscopic Resection of Intralabyrinthine Schwannomas: A Case Series

Objective: To investigate the technique and efficacy of fully endoscope resection of intralabyrinthine schwannomas (ILS) by transcanal transpromontorial endoscopic approach (TTEA). Study Design: Retrospective case review. Setting: Hospital. Patients: All patients who were affected by ILS, without extension to the internal auditory canal and underwent surgery with TTEA in our hospital in 2020. Intervention(s): Therapeutic. Main Outcome Measure(s): Recovery status, postoperative complications and remaining symptoms after surgery. Results: Three patients were included, all of which underwent gross total resections. The follow-up period was from 10 months to 2 years. No intraoperative and postoperative major complications were observed. There was no facial paralysis or cerebrospinal fluid leakage postoperatively. The hospitalization time of TTEA was 5 days. Three patients' vertigo was relieved after 1 week without receiving vestibular therapy. Only 1 patient complained of transient episodes of vertigo when climbing or holding heavy objects. Conclusions: TTEA has the advantages of clear vision to identify the anatomical structure, enabling complete tumor resection, reduced operation time, and faster postoperative recovery.Level of Evidence: IV.

Intralabyrinthine schwannomas: a two-case series and literature review with a focus on hearing rehabilitation

PURPOSE

Intralabyrinthine schwannomas (ILSs) are an uncommon finding. Diagnosis is challenging and no gold standard treatment exists yet. In this article, we present a two-cases series and review the latest available literature to assess the best diagnostic and therapeutic scheme.

METHODS

We reviewed the latest available literature assessing most frequent and relevant sets of symptoms, clinical features of the disease, diagnostic tests and imaging, possible treatments and after-surgery hearing rehabilitation techniques. We then compared literature data to our own series ones.

RESULTS

ILSs clinical presentation and development may overlap with other, more common otological conditions. Full audiometric battery test, electrophysiological study of VEMPS and MRI with contrast enhancement all appear to be critical to correctly diagnose these tumors. Several treatments exist: radiological follow-up, radiation therapy, full or partial surgical excision. Hearing rehabilitation is mostly accomplished through simultaneous cochlear implantation.

CONCLUSIONS

Our case-series data matches the available literature. ILSs are a rare type of vestibular schwannomas. Diagnosis in challenging and delayed in time as all the diagnostic tests, yet sensitive, are not specific for ILSs. The most suitable treatment seems to be surgical excision of these tumors followed by simultaneous cochlear implantation to restore hearing.

The Natural History of Primary Inner Ear Schwannomas: Outcomes of Long-Term Follow-Up

OBJECTIVE

To describe the natural history of primary inner ear schwannomas over a long follow-up period.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients with primary inner ear schwannomas with serial audiometric and radiologic follow-up.

MAIN OUTCOME MEASURES

Patterns of hearing loss, rate of hearing decline, presence of vestibular symptoms, and rate of tumor growth.

RESULTS

A total of 12 patients with 13 tumors were identified. The mean duration of follow-up was 7 years. Forty-six percent of tumors were intracochlear, 15% were intravestibular, 23% were transmodiolar, and 15% were intravestibular-cochlear. Hearing loss was the most common presenting symptom, occurring in all patients. Among patients with serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery Class A or B) at the time of presentation, the average time to decline to a nonserviceable hearing level was 57.3 months (range, 21-117 mo). Hearing loss was sudden in 31% of patients, progressive in 61% and fluctuating in 8%. No patients had intractable vertigo; however, two required vestibular physiotherapy. On initial magnetic resonance imaging, the mean largest tumor dimension was 3.1 mm (standard deviation, 1.2 mm), and the mean largest dimension on most recent magnetic resonance imaging was 4.4 mm (standard deviation, 1.1 mm). Two tumors exhibited no growth over a follow-up of 11.3 and 2.8 years, respectively. Overall, the mean growth was 0.25 mm per year followed. Two patients underwent cochlear implantation with simultaneous tumor resection and had favorable outcomes.

CONCLUSION

Long-term follow-up suggests a conservative approach, with possible hearing rehabilitation at the time of deterioration, is a safe management strategy for primary inner ear schwannomas.

A Case Report of Hemifacial Spasm Caused by Vestibular Schwannoma and Literature Review

BACKGROUND

Most cases of hemifacial spasm result from mechanical compression at the root exit zone of the facial nerve by vascular loops, and only a few cases are caused by vestibular schwannoma.

CASE PRESENTATION

We report a case of symptomatic hemifacial spasm induced by a small vestibular schwannoma that was totally resected. A 64-year-old man was admitted to our department with a 14-month history of symptomatic right-sided hemifacial spasm. During the process of microvascular decompression, no definite vessel was found to compress the facial nerve. By further exploration of regions other than root exit zone, a small vestibular schwannoma compressing the internal auditory canal portion of facial nerve from the ventral side was discovered. Resection of the tumor was then conducted. The symptoms of hemifacial spasm disappeared immediately after surgery.

CONCLUSIONS

We should be aware that magnetic resonance imaging is not always precise and perhaps misses some miniature lesions due to present image technique limitations. A small vestibular schwannoma might be the reason for HFS, although preoperative magnetic resonance tomography angiography showed possible vascular compression at the facial nerve root. More importantly, a full-length exploration of the facial nerve is in urgent need to find potential compression while performing microvascular decompression for HFS patients.

Intralabyrinthine Schwannoma: Distinct Features for Differential Diagnosis

Objectives: The aim of this study was to delineate the clinical and laboratory features suggestive of intralabyrinthine schwannoma (ILS). Methods: We compared the clinical features of 16 patients with ILS, who had been diagnosed at the Seoul National University Bundang Hospital from 2003 to 2018, with those of 18 patients with symptomatic unilateral intracanalicular schwannoma and randomly selected 20 patients with definite or probable unilateral Meniere's disease (MD). Results: Patients with ILS presented with either recurrent spontaneous dizziness/vertigo combined with auditory symptoms (n = 8), isolated auditory symptoms without dizziness/vertigo (n = 7), or recurrent spontaneous dizziness/vertigo without auditory symptoms (n = 1). Most patients reported no improvement (n = 11) or worsening (n = 1) of the symptoms despite medical treatments including intratympanic (n = 5) or intravenous steroids (n = 2). Conventional brain MRIs failed to detect ILS in about a half of the patients (7/16, 44%). However, ILS showed a filling defect on 3-dimensional (3D) heavily T2-weighted MRIs (n = 12), and nodular enhancement on 3D contrast-enhanced T1 (n = 15) or FLAIR MRIs (n = 13) targeted for the inner ear. Compared to MD or intracanalicular schwannoma, ILS showed mostly abnormal head-impulse tests (HITs, p = 0.001). In contrast, the incidence of canal paresis did not differ among the groups (p = 0.513). Conclusion: ILS may mimic MD by presenting recurrent dizziness/vertigo and auditory symptoms. ILS should be suspected in patients with recurrent audiovestibulopathy especially when (1) the duration of the dizziness is not typical for MD, (2) the patients do not respond to medical treatments, or (3) HITs are abnormal.

Combined surgical approach to intralabyrinthine schwannoma

INTRODUCTION

Intralabyrinthine schwannoma (ILS) is a tumor originating from the Schwann cells in the inner ear. Various surgical approaches can be used for the resection of ILS. The aim of this report is to describe a case involving a 60-year-old man who was treated successfully with a combined surgical approach.

CASE REPORT

The patient underwent a combined microscopic (transmastoid labyrinthectomy) and endoscopic procedure for surgical excision of ILS involving the vestibule and the lower half of the cochlear basal turn. The combined surgical technique enabled a complete removal of the ILS without removal of the unaffected cochlea as well as the external auditory canal. Besides additional exclusion of the middle ear, blind-sac closure of the external auditory canal and cavity obliteration were avoided. No postoperative complications were observed.

DISCUSSION

A combined microscopic and endoscopic approach to surgery enables removal of the ILS involving the vestibule and the lower half of the cochlear basal turn while helping to reduce surgical radicality.

Intralabyrinthine Schwannomas: Disease Presentation, Tumor Management, and Hearing Rehabilitation

Intralabyrinthine schwannomas (ILS) are rare tumors that frequently cause sensorineural hearing loss. The development and increased use of magnetic resonance imaging in recent years have facilitated the diagnosis of these tumors that present with otherwise nondiscriminant symptoms such as tinnitus, vertigo, and hearing loss. The following is a review of the presentation, pathophysiology, imaging, and treatment with a focused discussion on auditory rehabilitation options of ILS.

Ocular vestibular evoked myogenic potentials and intravestibular intralabyrinthine schwannomas

Intravestibular intralabyrinthine schwannomas (ILSs) are uncommon benign tumors that arise from the saccular, utricular, and lateral and superior ampullary nerves. According to the literature, there is an average delay of 8 years between the onset of symptoms and diagnosis. The diagnosis is based on an audiovestibular examination and magnetic resonance imaging (MRI). We describe a case of intravestibular ILS in which we included the ocular vestibular evoked myogenic potentials (oVEMPs) test in the diagnostic workup. The oVEMPs test is a relatively new neurophysiologic diagnostic modality that evaluates the superior vestibular pathway and the ascending contralateral pathway through the vestibulo-ocular reflex. In our case, a 65-year-old man presented with progressive right-sided sensorineural hearing loss, dizziness, and tinnitus and fullness in his right ear. Audiovestibular examination and MRI detected an intravestibular ILS on the right. We found that oVEMPs were absent on the contralateral side, which contributed to the diagnostic process. The detection of oVEMPs can provide detailed information on the functionality of the macula of the utricle and the lateral and superior ampullary nerves, with a precise identification of the affected area. Based on our findings, we discuss the role of oVEMPs in the diagnosis of an intravestibular ILS.

Intralabyrinthine schwannomas: a new surgical treatment

OBJECTIVE

To define a new surgical option, with lower morbidity, for the treatment of intralabyrinthine schwannomas.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral centers.

PATIENTS

Eight patients affected by an intralabyrinthine schwannoma, with or without extension to the internal auditory canal, that underwent surgery with a transcanal transpromontorial approach, were included in the study. The average age at presentation was 47 years. Patients' characteristics, symptoms, tumor features, and surgical results were analyzed.

INTERVENTIONS

All patients were diagnosed and evaluated pre-operatively with high-resolution, gadolinium-enhanced MRI and CT scan of the temporal bone, and underwent surgery via either transcanal transpromontorial endoscopic approach (TTEA) or enlarged transcanal transpromontorial endoscopic approach (ETTA).

MAIN OUTCOME MEASURES

Hearing function was evaluated with the Hearing Classification System according to the Committee on Hearing and Equilibrium Guidelines. Facial nerve function was evaluated using the House-Brackmann grading system (HB).

RESULTS

In six patients out of eight, a TTEA was performed, whereas, due to the extension of the pathology to the cerebellopontine angle, two patients underwent an ETTA. The mean follow-up period was 15.5 months (range 1-69). No intra-operative and post-operative major complications were observed. Post-operative facial nerve function was normal in seven out of eight patients (grade I HB). One patient presented a grade II HB.

CONCLUSION

The endoscopic approach to cochlear schwannoma represents a good treatment option for patients and should be preferred to other more invasive surgical techniques when indicated, to reduce complications, hospitalization, and offer to patients the chance to eradicate the disease, thus avoiding the stress of a long-life radiological follow-up.

LEVEL OF EVIDENCE

4.

Primary Solitary Intralabyrinthine Schwannoma: A Report of 7 Cases and a Review of the Literature

Intralabyrinthine schwannomas (ILSs) are uncommon benign tumors that originate in the Schwann cell sheath of the intralabyrinthine distal branches of the vestibulocochlear nerve. They have no initial involvement in the internal auditory canal although that might develop later. These lesions can arise inside the cochlea, originate in the vestibule or, in rare cases, develop in the semicircular canals. From these sites, spread might take place via the anatomic connections between the perilymphatic spaces in the scala vestibuli and the anterior vestibule. Thus, ILSs centered in the cochlea might involve the vestibule, and those originating in the vestibular end organs would reach the cochlea. Presenting signs and symptoms include a progressive or sudden sensorineural hearing loss (which occurs in more than 95% of patients), as well as tinnitus and vertigo. Magnetic resonance imaging characteristics include sharp circumscription and hypointensity on thin, heavily T2-weighted 3D images and strong enhancement after gadolinium administration on TI-weighted images. We describe a series of 7 cases of primary ILS that were managed at two of our institutions. We also discuss the need for a comprehensive otoneurologic evaluation that encompasses the functional derangement and the tumor location as delineated by MRI, and we describe the treatment options.

Clinical presentation of intralabyrinthine schwannomas: a multicenter study of 110 cases

OBJECTIVE

To describe the presentation of intralabyrinthine schwannomas (ILSs).

STUDY DESIGN AND SETTING

Retrospective multicenter study involving 12 European skull base surgery tertiary referral centers.

PATIENTS

One hundred ten patients with the diagnosis of ILS, either labyrinth confined or extending into the internal auditory meatus for less than 50% of their volume.

MAIN OUTCOME MEASURES

Data collected were age, sex, nature and timing of presenting symptoms, hearing (according to the AAO-HNS grading system), results of vestibular tests (caloric tests and cervical vestibular-evoked myogenic potentials [c-VEMPs]), and tumor localization. Presenting symptoms and laboratory test results were studied according to the extension of the lesion into the cochlea (C) and vestibule (V), on one hand, and according to unifocal (L1) or plurifocal (L2) extension into the labyrinth, on the other.

RESULTS

Intracochlear type was more common (50%) than vestibular (19.1%) and more diffuse forms (30.9%). The mean delay for diagnosis was long (72.5 mo; SD, 76.6). Mean age was 53.9 years (SD, 13.2). Deafness was the most common symptom (77.8 dB HL [SD, 33.6], with only 24.6% of patients keeping viable hearing. Caloric tests (65.5% of patients) were abnormal in 77.8% of cases. c-VEMPs were abnormal in 65.7% of the 36 cases analyzed. In V forms, hearing was significantly better (class A + B in 21.1% in C and 45.8% in V forms) (p = 0.03), and vestibular function was more altered (C: 57%, V: 100%, p = 0.0009*). L2 forms were diagnosed later (L1: 59.1 mo, L2: 104.5 mo; p = 0.004*) and were associated more frequently with a dead ear (L1: 13.1%, L2: 41.2%, p = 0.002*) than L1 forms.

CONCLUSIONS

This series, which is the largest in the literature, demonstrates that even very small and localized ILSs heavily compromise labyrinthine functions.

Meta-analysis on the clinical outcomes in patients with intralabyrinthine schwannomas: conservative management vs. microsurgery

The objective of this review is to compare the symptomatological evolution following conservative management (CM) or microsurgery (MS) in patients with intralabyrinthine schwannomas (ILS). A thorough systematic review of the English and French literature from 1948 to February 2014 was performed using Ovid Medline. An ancestor search was also completed. The major inclusion criterion consisted of a diagnosis of ILS with magnetic resonance imaging. Patients with a classic vestibular schwannoma, cases of incidentaloma during surgery or an autopsy were the main exclusion criteria. Thirty-one studies met our selective criteria. Descriptive data were collected from the articles. Clinical outcomes regarding the hearing loss, tinnitus, vertigo, dizziness and aural fullness were stated as improved, unchanged or worse at the last follow-up. All data were then separated into two different groups according to the management option: CM and MS. The data were analyzed using a Pearson χ (2) test and Fisher's exact test. This meta-analysis suggests that MS has a statistically significant favorable outcome regarding symptom relief compared to CM in patients with ILS suffering from tinnitus, vertigo and dizziness. Hearing level was not compared between treatment groups, as MS leads to anacusis. An indicative bias was the main limitation of this study, as patients suffering from intractable vertigo with moderate-to-severe hearing loss were referred to MS. Therefore, in the presence of a serviceable hearing, we suggest that CM should be the treatment of choice.

Recovery of hearing after surgical removal of intralabyrinthine schwannoma

Intralabyrinthine schwannomas (ILSs) are rare benign tumors arising from the distal part of the cochleovestibular nerve confined within the labyrinth. Patients with ILSs complain of hearing loss, vertigo, tinnitus, and ear fullness. Surgical treatment of ILS is performed in special cases such as in cases of patients with nonserviceable hearing, progressive hearing loss, intractable vertigo, or tumor extension. We present an unusual case of a patient with intralabyrinthine schwannoma who underwent surgery to treat progressive hearing loss and recovered his hearing after surgery.