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|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 2 | Page : 195-196
Vagal nerve schwannoma extending from cerebellopontine angle to cervical region straddling across the jugular foramen
Harsimrat Bir Singh Sodhi, Pravin Salunke, Sushanta K. Sahoo
Department of Neurosurgery, PGIMER, Chandigarh, India
|Date of Submission||08-Dec-2013|
|Date of Decision||06-Jan-2014|
|Date of Acceptance||13-Apr-2014|
|Date of Web Publication||14-May-2014|
Department of Neurosurgery, PGIMER, Chandigarh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sodhi HB, Salunke P, Sahoo SK. Vagal nerve schwannoma extending from cerebellopontine angle to cervical region straddling across the jugular foramen. Neurol India 2014;62:195-6
|How to cite this URL:|
Sodhi HB, Salunke P, Sahoo SK. Vagal nerve schwannoma extending from cerebellopontine angle to cervical region straddling across the jugular foramen. Neurol India [serial online] 2014 [cited 2020 Sep 22];62:195-6. Available from: http://www.neurologyindia.com/text.asp?2014/62/2/195/132396
Vagal nerve schwannomas are relatively uncommon lesions. ,,, In general, these lesions occur along the extracranial course of the nerves or may present as jugular foramen tumors.  We present a vagal nerve schwannoma straddling across the jugular foramen, both into intra and extracranial compartment (neck).
A 40-year-old female patient presented with hoarseness of voice with swallowing difficulty for 1 year and decreased hearing in right ear for last 4 months. Examination revealed weak bilateral gag reflex with afferent and efferent involvement, right side more than left, subtle right facial nerve paresis with right sensorineural deafness, and right sided cerebellar signs. Magnetic resonance imaging brain and upper cervical spine revealed a large lobulated, heterogeneously enhancing lesion straddling across the jugular foramen, extending from cerebellopontine (CP) angle to the C3 vertebral body [Figure 1]. Computed tomography (CT) head showed widening of the jugular foramen on right side with its evident erosion and ragged margins [Figure 2]a and b. CT-angiogram showed no flow voids and the internal carotid was pushed medially and slightly posterior [Figure 2]c-e.
|Figure 1: (a-c) Coronal T2-weighted magnetic resonance imaging (MRI) showing heterogeneously hyperintense lesion straddling across the right jugular foramen from cerebellopontine (CP) angle to cervical region. (d) T1-weighted MRI showing homogenous hypointense lesion in CP angle. (e) Parasgittal Contrast enhanced MRI image passing through jugular foramen showing heterogeneously enhancing lesion with cyst (black solid arrow) straddling across the jugular foramen. The jugular vein can be appreciated posterior to it (white arrow). (f-h) axial MRI images at CP angle level, jugular foramen and the cervical level respectively; showing the lesion|
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|Figure 2: (a and b) Axial computed tomography (CT) showing widening of right jugular foramen (black arrows). (c-e) Reconstructed CT angiogram (antero-posterior and lateral) showing medially and posteriorly pushed right internal carotid artery (white arrows)|
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Patient was operated (by the senior author PS) in supine position with head turned to the left, exposing both posterior fossa and anterolateral neck. A curvilinear incision was given posterior to pinna up to hyoid bone, along the anterior border of sternocleidomastoid. Initially, right suboccipital craniectomy was performed reaching up to occipital condyle. Jugular foramen was opened tracing the sigmoid sinus. The friable grayish tumor in the CP angle cistern was excised maintaining the arachnoid plane. The neck portion of the lesion was seen between the congested internal jugular vein and carotid. The lesion was seen arising from the fibers of vagus and was eccentrically placed within carotid sheath growing between the carotid and jugular vein. Majority of the cervical component was removed, while maintaining the continuity of the vagus nerve. On tumor excision a small probe could be easily passed across the jugular foramen, through the neck visualizing it into the CP angle. Histopathology confirmed schwannoma. Her hearing and facial paresis improved completely after 4 months. She does complain of occasional cough on swallowing.
Common jugular foramen lesions include lower cranial nerve schwannomas and glomus jugulare tumors. Based on the location, tumors in relation to the jugular foramen can be classified as: type A tumors, with primary intracranial involvement, Type B tumors, with primary involvement of the jugular foramen with or without intracranial component, Type C tumors, primarily extracranial, and Type D - saddle bag or dumb-bell intra and extracranial tumor. , In short, the location depends on the site of origin from the nerves: cisternal, foraminal and extracranial. Tumors originating from cisternal part grow toward the CP angle mimicking an acoustic schwannoma; those from the foraminal portion predominantly expand the bone and jugular foramen and present with involvement of lower cranial nerves; and tumors originating from the extracranial part present with major extracranial growth, and may extend to the parapharyngeal space inferiorly presenting as neck mass. Intracranial and foraminal tumors have the longer duration as opposed to extracranial tumors, because of their slow insidious growth pattern.  Of these, vagal nerve schwannomas are rare. ,, Even large reported series of jugular foramen schwannomas have only a few Type D lesions. ,,] However, the exact site of origin of these Type D tumors is unclear in any of the above series. The site of origin is likely to determine the growth. A lesion arising from inferior ganglion mainly produces a extracranial mass whereas the superior ganglion produces an intracranial lesion.  However, this theory cannot explain Type D lesion. The clinical features are usually those of jugular foramen schwannomas. Occasionally, they may present with hypertension.  Appropriate radiological evaluation differentiates vagal nerve schwannoma from glomus jugulare tumors. Lack of vascular blush and flow voids in a heteregenously enhancing tumor favors the diagnosis of schwannoma. Vagal nerve lesions usually displace the carotid anteriorly.  However, in our case carotid artery was pushed medially and the tumor was seen popping out between the jugular vein and the carotid.
Preoperative planning is extremely important as total excision bears a good outcome in schwannomas. The intracranial and extracranial component can be approached separately or in the same sitting. If required, facial nerve transposition and mandibulectomy can be done to excise a large extracranial component just outside the jugular foramen. These lesions are usually eccentric and the vagal nerve can be preserved.
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[Figure 1], [Figure 2]