CASE 15589 Published on 11.05.2018

Glossopharyngeal schwannoma

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Eliza Stavride, Katerina Manavi, Marianna Theodorou, Melpomeni Kosmidou, Antonios Theodorakopoulos, Ioannis Tsitouridis

Papageorgiou General Hospital of Thessaloniki,Radiology; Pavlos Melas Street 56429 Thessaloniki, Greece; Email:elizasta@hotmail.com
Patient

86 years, female

Categories
Area of Interest Neuroradiology brain ; Imaging Technique MR
Clinical History

A 86-year-old woman presented to our hospital complaining of vertigo, tinnitus and gait ataxia dating back 6-7 months.There was history of hypertension and hypothyroidism under medical treatment. No hearing loss or dysphagia was admitted. She was investigated with magnetic resonance imaging (MRI) which revealed the mass.

Imaging Findings

MRI revealed a well-demarcated, round, solid mass in the right cerebellomedullary cistern, which was hypointense on T1-weighted images (T1WI) and hyperintense on T2-weighted images (T2WI). The mass was conspicuously enhanced on contrast administered T1-weighted image. Based on clinical and imaging features, a diagnosis of schwannoma of the IX or X nerve was made. The patient underwent left retromastoid suboccipital craniectomy and total excision of the tumour. The tumour was found to be attached at the ninth cranial nerve. At the surgery, a large, soft, cystic mass with a fragile capsule was found, occupying the cerebellomedullary cistern. Histopathology of the mass showed Antoni A and Antoni B areas typical of schwannoma.

Discussion

Neurinomas or schwannomas represent approximately 7-10% of all primary intracranial tumours. [1] The cerebellopontine angle is the most frequent site of origin and the eighth nerve is the most commonly involved. Rarely are other cranial nerves involved, in descending order of frequency it is the fifth nerve, seventh nerve and twelfth nerve. [2]
The usual symptoms of glossopharyngeal schwannomas include hearing loss, tinnitus vertigo, gait ataxia, headache, nystagmus, hoarseness, palate-pharyngeal and facia hypoestesia, rarely papilloedema and dysphagia. [3] Symptoms may not manifest until the tumour attains a fairly large size. However, since the posterior fossa is a small compartment, multiple cranial nerves may be affected simultaneously. Palsies of the ninth cranial nerve are unusual and symptoms of ninth nerve dysfunction may not become apparent until there is bilateral involvement. [4] The clinical presentation and radiological findings closely mimic acoustic schwannomas, and the identification of the nerve of origin of the tumour often cannot be established preoperatively. [2] The preoperative clinical evaluation can lead to a suspected diagnosis of involvement of the cerebellopontine or even cerebellomedullary angle and possibly the jugular foramen, but is otherwise not specific. Radiologic workup, including Computed Tomography (CT), angiography, or plain X-ray, can localise the lesion to the jugular foramen, but again, does not distinguish the particular nerve of origin of the tumour. [5]
Samii and Tatagiba classified tumour extension in relation to the radiological and surgical features into Type A, B, C and D. Type A tumour being primarily located at the level of cerebellopontine angle with minimum enlargement of jugular foramen, type B tumour primarily in jugular foramen with intracranial extension, type C primarily being an extracranial tumour with extension into jugular foramen and type D being a dumb bell-shaped tumour with both intra and extracranial components. [6]

Differential Diagnosis List
Glossopharyngeal schwannoma
Acoustic neurinoma
Schwannoma of the X/XI cranial nerve
Meningioma
Final Diagnosis
Glossopharyngeal schwannoma
Case information
URL: https://www.eurorad.org/case/15589
DOI: 10.1594/EURORAD/CASE.15589
ISSN: 1563-4086
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