Parapharyngeal Schwannomas

Abstract

Schwannomas of the parapharyngeal space are rare benign tumors arising from nerves located in the parapharyngeal space. Most of them occur as a mass behind the ascending ramus of the mandible, and bimanual palpation is important in ascertaining their exact location. The anatomy of the parapharyngeal space is described in detail. Treatment of these tumors is surgical through an external neck approach. A combined neurosurgical approach is indicated for tumors extending intracranially. Four cases of parapharyngeal schwannomas are added to the world literature (114 reported), with one extending intracranially through the jugular foramen.

Hypoglossal Schwannoma of Parapharyngeal Space: An Unusual Case Report

“…Schwannomas are uncommon benign tumors of nerve that are usually slow growing and asymptomatic [5,6]. Approximately 25-45% of the cases occur in the head and neck region and are sometimes (8-19%) associated with Neurofibromatosis type-1 (NF-1) [7,8].…”

“…Male-female ratio for schwannoma of head and neck is almost equal or has a slight preponderance for males (61.9%) than females (38.1%). Incidence of cervical sympathetic chain schwannomas is either equal or in ratio of 3:1 [5,12]. In case of vagus nerve schwannomas there is no sex related predisposition [6,13].…”

“…The differential diagnosis of the parapharyngeal space lesions include tumors of the deep lobe of the parotid gland, tumors of minor salivary gland, metastatic cervical nodes, paragangliomas, branchial cysts, lymphomas, neurofibromas, and aneurysms of the internal carorid artery [5,6].…”

“…The transcervical surgical approach to the parapharyngeal space is the preferred operating procedure. If the schwannoma is completely removed, recurrence rates are extremely low [5]. Recently, intracapsular enucleation has been introduced which preserve the nerve fibres, and there by the neurological functions [19].…”

Cervical Sympathetic Chain Schwannoma: A Case Report

“…Schwannomas are benign solitary nerve sheath tumors arising from any nerve with Schwann cells except olfactory and optic which lack them [3,4]. In the head and neck region they arise most commonly from the parapharyngeal space [3].…”