Vagus Nerve Schwannoma [Neurosurgery Wiki]

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====== Vagus 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
((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.
)).
===== Clinical features =====
They usually presents as an asymptomatic slow growing mass
((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.
)).

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
((https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3227827/)).

===== 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.

A 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
((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.
)).

----

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
((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.
)).

===== Outcome =====
Nerve damage during surgical resection is associated with significant morbidity
((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.
)).

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
((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.
)).

===== Case series =====

[[Vagus Nerve Schwannoma case series]].


===== Case reports =====

[[Vagus Nerve Schwannoma case reports]].

===== References =====