Facial nerve schwannomas: A case series with an analysis of imaging findings

Abstract

Facial nerve schwannomas (FNSs) are rare benign tumors arising from the Schwann cells of the sheath of the facial nerve. These tumors may arise anywhere along the course of the facial nerve. Owing to their rarity and nonspecific clinical and radiological presentations, the preoperative diagnosis of FNSs is exceedingly difficult. In this study, we present four cases of histopathologically proven extratemporal schwannomas and a solitary case of intratemporal schwannoma. The purpose of this study was mainly focused on analyzing the imaging findings of extratemporal and intratemporal schwannomas in an effort to better characterize these lesions preoperatively. An early diagnosis of FNSs is helpful for the management and rehabilitation of these cases.

Schwannoma of the Zygomatic Branch of the Facial Nerve

“…Schwannomas are benign neurogenic, usually encapsulated, neoplasms that derive from the Schwann cells of the sheath of peripheral nerves, including the distal parts of most cranial nerves. 1,2 These tumors can be found anywhere in the body but are mostly described in the head and neck, especially in the maxillofacial area. 3 Facial nerve schwannomas are very rare.…”

“…3 Facial nerve schwannomas are very rare. 1 They can include one or more portions of the facial nerve and are mainly unilateral. 4 Bilateral FNSs are associated with neurofibromatosis type 2.…”

“…4 They can be categorized into extratemporal (mainly refer to the intraparotid segment of the facial nerve) and intratemporal (tumors involving temporal segments of the facial nerve) types. 1 The majority (about 90%) are related to the intratemporal part of the nerve. 5 The clinical presentation of FNSs depends on their location with extratemporal tumors presenting as painless swellings of the parotid gland without facial nerve palsy.…”

“…5 The clinical presentation of FNSs depends on their location with extratemporal tumors presenting as painless swellings of the parotid gland without facial nerve palsy. 1,5 Even less often, extratemporal FNSs that do not affect the parotid gland manifest themselves as asymptomatic swellings of the facial region. 1 Most common symptoms of an intratemporal FNS are sensorineural hearing loss, vertigo, tinnitus, and facial nerve dysfunction.…”

“…1,5 Even less often, extratemporal FNSs that do not affect the parotid gland manifest themselves as asymptomatic swellings of the facial region. 1 Most common symptoms of an intratemporal FNS are sensorineural hearing loss, vertigo, tinnitus, and facial nerve dysfunction. 6 Generally, the preoperative diagnosis of an FNS is challenging.…”