Facial nerve schwannoma

Facial nerve schwannoma

Facial nerve schwannoma may arise in any portion of the facial nerve, with a predilection for the geniculate ganglion 1) 2).

They can occur anywhere from the internal auditory canal to the parotid gland. Schwannomas arising from the greater superficial petrosal nerve are exceedingly rare 3).

Clinical

Even in these tumors, hearing loss tends to precede facial paresis. Hearing loss may be sensorineural from VIII cranial nerve compression from tumors arising in the proximal portion of VII cranial nerve (cisternal or internal auditory canal (IAC) segment), or it may be conductive from erosion of the ossicles by tumors arising in the second (tympanic, or horizontal) segment of VII. Facial palsy (peripheral) may also develop, usually late 4).

Diagnosis

Computed tomography (CT) of the temporal bone is important for evaluating the impact on the surrounding structures 5).

Treatment

Treatment for intracranial facial nerve schwannomas depends on clinical presentation, tumor size, preoperative facial, and hearing function.

Conservative management is recommended for asymptomatic patients with small tumors. Stereotactic radiosurgery may be an option for smaller and symptomatic tumors with good facial function. If tumor is large or the patient has facial paralysis, surgical resection should be indicated. If preservation of the facial nerve is not possible, total resection with nerve grafting should be performed for those patients with facial paralysis, whereas subtotal resection is best for those patients with good facial function 6).

see Middle Fossa Approach for Facial Nerve Schwannoma.


These tumors must be assessed with imaging studies, incisional biopsy is not recommended. The treatment is surgical resection in symptomatic patients with facial paralysis greater than grade III of House-Brackmann, with immediate reconstruction of the nerve 7).

Case series

Facial nerve schwannoma case series.

Case reports

Facial nerve schwannoma case reports.

References

1) , 4)

Inoue Y, Tabuchi T, Hakuba A, et al. Facial Nerve Neuromas: CT Findings. J Comput Assist Tomogr. 1987; 11:942–947
2)

Tew JM, Yeh HS, Miller GW, Shahbabian S. Intratemporal Schwannoma of the Facial Nerve. Neurosurgery. 1983; 13:186–188
3)

Sade B, Lee JH. Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma. Case report. J Neurosurg. 2007 Jul;107(1):181-4. PubMed PMID: 17639892.
5)

Loos E, Wuyts L, Puls T, Foer B, Casselman JW, Bernaerts A, Vanspauwen R, Offeciers E, Dinther JV, Zarowski A, Somers T. Cochlear Erosion due to a Facial Nerve Schwannoma. J Int Adv Otol. 2019 Jul 9. doi: 10.5152/iao.2019.5304. [Epub ahead of print] PubMed PMID: 31287431.
6)

Xu F, Pan S, Alonso F, Dekker SE, Bambakidis NC. Intracranial Facial Nerve Schwannomas: Current Management and Review of Literature. World Neurosurg. 2017 Apr;100:444-449. doi: 10.1016/j.wneu.2016.09.082. Epub 2016 Sep 28. Review. PubMed PMID: 27693767.
7)

Prado-Calleros HM, Corvera-Behar G, García-de-la-Cruz M, Calderón-Wengerman Ó, Prado A, Pombo-Nava A. Tympanic-mastoid and parotid schwannomas of the facial nerve: clinical presentation related to the anatomic site of origin. Cir Cir. 2019;87(4):377-384. doi: 10.24875/CIRU.18000449. PubMed PMID: 31264987.

Vagal Nerve Schwannoma

Vagal Nerve Schwannoma

Epidemiology

Schwannoma arising from the vagus nerve is an uncommon (2–5%) benign nerve tumour.

Vagal Nerve Schwannomas are usually confined to the retrostyloid parapharyngeal space, although patients with schwannomas that extend into the posterior cranial fossa through the jugular foramen have been reported


Schwannomas arising from the vagus nerve are extremely rare in children, with only 16 cases reported in the world literature 1).

Clinical features

They usually presents as an asymptomatic slow growing mass 2).

Most cases of schwannomas manifest between the third and sixth decades of the patient’s life as a slow growing firm, painless mass in the lateral neck. Hoarseness, pain, or cough may be the presenting complaints. They displace the carotid arteries anteriorly and medially, jugular vein laterally and posteriorly. These swellings are mobile transversely but not vertically 3).

Diagnosis

Diagnosis is based on clinical suspicion and confirmation obtained by means of surgical pathology.

Differential diagnosis

Schwannomas of the vagus nerve must be differentiated from the carotid body and glomus vagale tumors because the distinction may influence treatment planning.

Treatment

Surgical excision is the treatment of choice for vagal schwannoma, with recurrence being rare.


Intermittent intraoperative neuromonitoring via selective stimulation of splayed motor fibers running on the schwannoma surface to elicit a compound muscle action potential has been previously reported as a method of preserving vagal motor fibers.

In a case report, vagal sensory fibers were mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes 4).

Outcome

Nerve damage during surgical resection is associated with significant morbidity 5).

This tumour most often presents as a slow growing asymptomatic solitary neck mass, which rarely undergoes malignant transformation.

Literature review

In a comprehensive literature review on 197 articles reporting 235 cases of cervical vagal schwannomas. Presenting symptoms, treatment approach, and postoperative outcomes were recorded and analyzed.

Vagal schwannomas commonly present as asymptomatic neck masses. When they become symptomatic, surgical resection is the standard of care. Gross total resection is associated with higher postoperative morbidity compared to subtotal resection. Initial reports using intraoperative nerve monitoring have shown improved nerve preservation. Recurrence rates are low.

The combination of intermittent nerve mapping with novel continuous vagal nerve monitoring techniques may reduce postoperative morbidity and could represent the future standard of care for vagal schwannoma treatment 6).

Case series

Case series of three patients who underwent vagal schwannoma excision utilizing a IONM technique. The recurrent laryngeal and vagus nerves were monitored via the laryngeal adductor reflex (LAR) using an electromyographic endotracheal tube.

Three patients with suspected vagal schwannomas were treated surgically using the intracapsular enucleation approach with a combination of intermittent IONM and continuous IONM of the LAR.

This combination of continuous and intermittent IONM can be used to preserve vagal laryngeal innervation and function and may represent the future standard of care for vagal schwannoma excision 7).


Green et al. reported 36 of these rare neoplasms in 35 patients. The majority of the tumors presented as a mass in the upper cervical or parapharyngeal region. Usually the mass was asymptomatic. The following types and frequencies of neoplasms of the vagus nerve were noted: paragangliomas, 50%; neurilemmomas, 31%; neurofibromas, 14%; and neurofibrosarcomas, 6%. Surgical resection, with preservation of the vagus nerve when possible, is the treatment of choice. The clinical features, diagnosis, management, and prognosis of the tumors are presented. Special problems that occur with vagal neoplasms include postoperative dysfunction, catecholamine secretion, and intracranial or skull-base extension 8).

Case reports

In a case report, vagal sensory fibers were mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes 9).


Keshelava et al. operated one patient for cervical schwannoma causing internal carotid artery (ICA) compression.

The patient underwent en bloc excision via transcervical approach under general anesthesia. Pathological examination demonstrated the diagnosis of schwannoma.

This case shows that VNS can cause ICA compression and therefore brain ischemia 10).


Schwam et al. reported a purely intracranial vagal schwannoma 11).

2018

A 60-year-old female patient was seen at our service for a slow-growing, 9 × 6 cm left-sided cystic neck mass. Preoperative clinical and computed tomography evaluation suggested a diagnosis of a lateral neck cyst. The surgical exploration through the lateral cervicotomy revealed a large cystic mass and clearly identified that the tumor was originating from the left vagal nerve. The histopathologic analysis confirmed the diagnosis of schwannoma. Although uncommon, vagal schwannoma with pronounced cystic component should be included in the differential diagnosis of the cystic neck swellings 12).


A 55-year-old woman who presented to the clinic complaining of throat irritation and feeling of something stuck in her throat for the past three months. On examination, a bulging left parapharyngeal mass was noted, displacing the left tonsil and uvula medially. A contrast-enhanced computed tomography (CT) scan of the neck showed a large, hypervascular soft tissue mass with splaying of the left internal carotid artery. Intraoperatively, the tumor was found to be arising from the vagus nerve. Macroscopic surgical pathology examination showed a tan-red, ovoid, and firm mass. Histopathology showed a benign spindle cell tumor with Antoni A areas with palisading cell nuclei and some degenerative change, confirming the diagnosis of vagus nerve schwannoma. CONCLUSIONS Vagus nerve schwannomas should be distinguished from other tumors that arise in the neck before planning surgery, to minimize the risk of nerve injury. Physicians need to be aware of the differential diagnosis of a neck mass, investigations required, the surgical treatment and the potential postoperative complications 13).


Sreevatsa et al. described three cases of schwannoma involving the vagus who presented differently to our unit during past 5 years 14).


A large vagal neurilemmoma in a 33-year-old man is reported. He complained of slowly progressive palsy of the tongue on the left side. Weakness of soft palate movement was also noted. Magnetic resonance imaging (MRI) revealed a tumour in the left parapharyngeal space with partial extension to the posterior cranial fossa through the jugular foramen. Carotid angiography revealed avascularity of the tumour and anterior shift of the left internal carotid artery. The venous phase showed no blood flow in the internal jugular vein. The tumour was successfully extirpated via a transmandibular transpterygoid approach. Although vagus nerve dysfunction was not observed pre-operatively, the tumour was identified as a neurilemmoma arising from the vagus nerve. The surgical approach should be selected according to the lesion in individual patients. Since neurilemmoma is benign in nature, minimal post-operative sequelae should be expected 15).

References

1)

Mierzwiński J, Wrukowska I, Tyra J, Paczkowski D, Szcześniak T, Haber K. Diagnosis and management of pediatric cervical vagal schwannoma. Int J Pediatr Otorhinolaryngol. 2018 Nov;114:9-14. doi: 10.1016/j.ijporl.2018.08.021. Epub 2018 Aug 23. PubMed PMID: 30262374.
2) , 13)

Ramdass AA, Yao M, Natarajan S, Bakshi PK. A Rare Case of Vagus Nerve Schwannoma Presenting as a Neck Mass. Am J Case Rep. 2017 Aug 21;18:908-911. PubMed PMID: 28824161; PubMed Central PMCID: PMC5574523.
4) , 9)

Sinclair CF, Téllez MJ, Sánchez Roldán MA, Urken M, Ulkatan S. Intraoperative mapping and monitoring of sensory vagal fibers during vagal schwannoma resection. Laryngoscope. 2019 Dec;129(12):E434-E436. doi: 10.1002/lary.28147. Epub 2019 Jun 18. PubMed PMID: 31211430.
5) , 7)

Sandler ML, Sims JR, Sinclair C, Ho R, Yue LE, Téllez MJ, Ulkatan S, Khorsandi AS, Brandwein-Weber M, Urken ML. A novel approach to neurologic function sparing surgical management of vagal schwannomas: Continuous intraoperative nerve monitoring of the laryngeal adductor reflex. Head Neck. 2019 Sep;41(9):E146-E152. doi: 10.1002/hed.25793. Epub 2019 May 6. PubMed PMID: 31058386.
6)

Sandler ML, Sims JR, Sinclair C, Sharif KF, Ho R, Yue LE, Téllez MJ, Ulkatan S, Khorsandi AS, Brandwein-Weber M, Urken ML. Vagal schwannomas of the head and neck: A comprehensive review and a novel approach to preserving vocal cord innervation and function. Head Neck. 2019 Jul;41(7):2450-2466. doi: 10.1002/hed.25758. Epub 2019 Apr 7. Review. PubMed PMID: 30957342.
8)

Green JD Jr, Olsen KD, DeSanto LW, Scheithauer BW. Neoplasms of the vagus nerve. Laryngoscope. 1988 Jun;98(6 Pt 1):648-54. PubMed PMID: 2836676.
10)

Keshelava G, Robakidze Z. Cervical Vagal Schwannoma Causing Asymptomatic Internal Carotid Artery Compression. Ann Vasc Surg. 2019 Oct 17. pii: S0890-5096(19)30859-3. doi: 10.1016/j.avsg.2019.09.021. [Epub ahead of print] PubMed PMID: 31629844.
11)

Schwam ZG, Kaul VZ, Shrivastava R, Wanna GB. Purely intracranial vagal schwannoma: A case report of a rare lesion. Am J Otolaryngol. 2019 May – Jun;40(3):443-444. doi: 10.1016/j.amjoto.2019.02.011. Epub 2019 Feb 18. PubMed PMID: 30799212.
12)

Cukic O, Jovanovic MB. Vagus Nerve Schwannoma Mimicking a Lateral Neck Cyst. J Craniofac Surg. 2018 Nov;29(8):e827-e828. doi: 10.1097/SCS.0000000000005006. PubMed PMID: 30320693.
14)

Sreevatsa MR, Srinivasarao RV. Three cases of vagal nerve schwannoma and review of literature. Indian J Otolaryngol Head Neck Surg. 2011 Oct;63(4):310-2. Epub 2011 Apr 8. PubMed PMID: 23024932; PubMed Central PMCID: PMC3227827.
15)

Yumoto E, Nakamura K, Mori T, Yanagihara N. Parapharyngeal vagal neurilemmoma extending to the jugular foramen. J Laryngol Otol. 1996 May;110(5):485-9. PubMed PMID: 8762326.

Cervical spinal schwannoma

Cervical spinal schwannoma

Spinal schwannoma are most frequently seen in the cervical and lumbar regions, far more frequently than in the thoracic spine.

Classification

Asazuma Classification

1).


Eden’s classification for dumbbell tumors of the spine, long considered a “gold standard,”

no longer is sufficient to determine surgical strategy in view of recent advances in computed tomography and magnetic resonance imaging.

Treatment

Cervical dumbbell spinal schwannomas with an extraspinal extension through the intervertebral foramina pose significant challenges for complete resection while avoiding injury to the vertebral artery and preserving the integrity of the cervical spine. Posterior approaches may require an extensive soft-tissue dissection and bone removal with potential spinal instability. Moreover, they offer only a limited access to an extraspinal tumor component that entails an additional anterior approach for complete resection of a dumbbell-shaped lesion.

Goga et al., used an anterolateral transforaminal approach that preserves the bony elements of the intervertebral foramen and offers a comprehensive access to the extraspinal, foraminal and intraspinal/intradural components of a cervical dumbbell tumor 2).

Outcome

Cervical spinal schwannoma is benign, and outcomes after surgical resection are generally excellent. A surgical dilemma sometimes arises as to whether to perform total tumor removal, which carries a risk of sacrificing the nerve root, or subtotal removal, where the risk can be tumor recurrence.

Case series

Chowdhury et al. reported schwannomas arising from C1, C2 and C3 spinal nerve roots were regarded as high cervical spinal schwannoma. All patients with high cervical spinal schwannomas that were consecutively operated microneurosurgically from 2006-2010 were included in the study. Postoperatively all patients were followed up regularly both clinically and neuro-radiologically (MRI of cervical spine).

Average follow up was 31.5 months. The mean age of the series was 35.8 years (range 10-61 years). There were 8 male and 7 female patients. The mean duration of symptoms at the time of presentation was 32 months (range 06 months-5 years). Two schwannomas were completely extradural, seven were intradural and rest six were interdural or hourglass type (both extra and intradural) as identified during surgery. The standard midline posterior approach was used in all patients. A C2 hemilaminectomyor C2 laminectomy with or without cutting of posterior arch of atlas was used for most intradural and large interdural C2 schwannomas. Tumor removal was complete in all cases. Preservation of the nerve root fibers was not possible in 9 cases and was possible only in 3 cases. In two patients CSF leak developed after operation. One patient who had severe myelopathic features with bed sore failed toimprove and expired 5 months after operation. Rest of the patients showed postoperative improvement in their preoperative symptoms and returned to their normal life by the end of sixth month. There was no tumor recurrence in any patient till last follow up.

Proper 3-D anatomical orientation & physiological knowledge, deep neuro-radiological observation,pathological appreciations and micro-neurosurgical skill and expertization can make the surgical management of these tumors ( in a surgically complex site) simple with gratifying result (i.e.neurological outcome) without extensive bone removal or soft tissue manipulation through a standard midline posterior approach 3).


Thirty cases of cervical schwannomas treated by Yamane et al. were retrospectively reviewed;initial symptoms, tumor location, Eden classification, surgical method, functional outcome, and tumor recurrence were investigated. All permanent motor deficits were the result of resecting functionally relevant nerve roots (i.e., C5-8). The rate of permanent sensory deficit was 11% after C1-4 nerve root resection, and 67% after C5-8 nerve root resection. Permanent neurological deficits occurred in 14% of patients younger than 40 years and 38% of those older than 40. Dumbbell tumors were associated with the need for total or ventral nerve root transection, as well as with a high incidence of tumor recurrence. The incidence of permanent neurological deficit was significantly higher in patients undergoing C5-8 nerve root resection, and tended to be higher in those over 40 4).


Forty-two patients with cervical dumbbell tumors were analyzed retrospectively using a new three-dimensional classification.

To establish optimal surgical strategies, we considered shapes and three-dimensional locations of cervical dumbbell tumors based on diagnostic images and intraoperative findings.

Forty-two cervical dumbbell tumors were characterized according to transverse-section images (Toyama classification; nine types) and craniocaudal extent of intervertebral and transverse foraminal involvement (IF and TF staging; three stages each).

Type IIIa tumors, involving dura plus an intervertebral foramen, accounted for 50% of cases. A posterior approach was used in 35 patients; 7 others underwent a combined anterior and posterior approach. A posterior approach was used for all type IIa and IIIa tumors, and for some type IIIb (upper cervical), IV, and VI tumors; a combined posterior and anterior approach was used for type IIb and the remainder of type IV and VI. Reconstruction was performed using spinal instrumentation in 4 patients (9.5%). Resection was subtotal in 6 patients (14.3%) and total in 36 (85.7%).

Systematic, imaging-based three-dimensional characterization of shape and location of cervical dumbbell tumors is essential for planning optimal surgery. The classification used here fulfills this need 5).


Case reports

Pokharel et al. reported a case of extradural cervical schwannoma in a 14-year-old boy with swelling in the posterior triangle of his neck. The radiological features suggested solitary extradural cervical schwannoma which was confirmed later by histopathological findings. There were no postoperative neurological complications 6)


Perry et al. reported in 2019 the third case of synchronously presenting primary progressive multiple sclerosis (MS) and spinal schwannoma. A 65-year-old man presented with six months of progressive weakness and pain of the right shoulderforearm, and handMRI demonstrated a contrast-enhancing transforaminal lesion at C7, most consistent with a benign nerve sheath tumor. Additional history disclosed several years of worsening fatigue, accompanied by bilateral weakness and lancinating leg pain. MRI of the neuraxis demonstrated abnormalities consistent with chronic demyelinating disease intracranially and within the spinal cordcerebrospinal fluid (CSF) analysis revealed nine oligoclonal bands and an elevated IgG index, resulting in the diagnosis of MS. Given the symptomatic C7 lesion, the patient subsequently underwent right C6-C7 facetectomygross total resection of the tumor, and C6-T1 posterior instrumented fusion. Postoperatively, the patient rapidly recovered normal right upper extremity function, and pathology confirmed benign schwannoma. Synchronously presenting co-morbid neurologic diagnoses are exceedingly rare. Nonetheless, the high incidence and protean nature of MS make it particularly susceptible to such confounding clinical cases. Correspondingly, MS should be considered when neurologic abnormalities are not compatible with a focal radiographic lesion, and the present report emphasizes the value of a good history and exam in unraveling similarly challenging cases 7).

References

1) , 5)

Asazuma T, Toyama Y, Maruiwa H, Fujimura Y, Hirabayashi K. Surgical strategy for cervical dumbbell tumors based on a three-dimensional classification. Spine (Phila Pa 1976). 2004 Jan 1;29(1):E10-4. PubMed PMID: 14699292.
2)

Goga C, Türe U. The Anterolateral Transforaminal Approach to a Dumbbell Schwannoma of the C3 Nerve Root. A 3-Dimensional Operative Video. Neurosurgery. 2014 Sep 24. [Epub ahead of print] PubMed PMID: 25255264.
3)

Chowdhury FH, Haque MR, Sarker MH. High cervical spinal schwannoma; microneurosurgical management: an experience of 15 cases. Acta Neurol Taiwan. 2013 Jun;22(2):59-66. PubMed PMID: 24030037.
4)

Yamane K, Takigawa T, Tanaka M, Osaki S, Sugimoto Y, Ozaki T. Factors predicting clinical impairment after surgery for cervical spinal schwannoma. Acta Med Okayama. 2013;67(6):343-9. PubMed PMID: 24356718.
6)

Pokharel A, Rao TS, Basnet P, Pandey B, Mayya NJ, Jaiswal S. Extradural cervical spinal schwannoma in a child: a case report and review of the literature. J Med Case Rep. 2019 Jul 17;13(1):230. doi: 10.1186/s13256-019-2108-6. PubMed PMID: 31311599; PubMed Central PMCID: PMC6636037.
7)

Perry A, Peters P, Graffeo CS, Carlstrom LP, Krauss WE. Synchronous Presentation of a Cervical Spinal Schwannoma and Primary Progressive Multiple Sclerosis in a 65-year-old Man. Cureus. 2019 Mar 4;11(3):e4176. doi: 10.7759/cureus.4176. PubMed PMID: 31093475; PubMed Central PMCID: PMC6502288.
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