Facial nerve schwannoma [Neurosurgery Wiki]

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====== Facial nerve schwannoma ======

Facial nerve [[schwannoma]] may arise in any portion of the [[facial nerve]], with a predilection for the [[geniculate ganglion]]
((Inoue Y, Tabuchi T, Hakuba A, et al. Facial Nerve Neuromas: CT Findings. J Comput Assist Tomogr. 1987; 11:942–947))
((Tew JM, Yeh HS, Miller GW, Shahbabian S. Intratemporal Schwannoma of the Facial Nerve. Neurosurgery. 1983; 13:186–188)).

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





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

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

===== 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
((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.
)).

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
((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.
)).

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

[[Facial nerve schwannoma case series]].


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

[[Facial nerve schwannoma case reports]].

===== References =====