PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 25 no. 2 July – december 2010
CASE REPORTS
PhiliPPine Journal of otolaryngology-head and neck Surgery 23
ABSTRACT
Objectives: To present a case of cervical vagal schwannoma and describe our experience with
the clinical presentation, surgical management and outcome of an elderly patient with this
pathology.
Methods:
Design: Case Report
Setting: Tertiary Public Hospital
Patient: One
Results: A 65-year-old lady presented with a recently enlarging, pulsatile right sided neck mass
that had been asymptomatic for 15 years. Contrast CT revealed a circumscribed non-enhancing
heterogenous 4 x 4 x 7 cm mass splaying the right internal jugular vein and common carotid
artery. A neurogenic tumour was considered, and the mass was excised from the vagus nerve with
preservation of adjacent structures. Final histopathologic reading was schwannoma. However,
the patient succumbed to complications following a second surgery for expanding hematoma.
Conclusion: Schwannomas are benign, slow growing tumours that arise from Schwann cells of
the nerve sheath. Cervical schwannomas originating from the vagus nerve are rare but should
be considered in patients presenting with solitary neck masses. Surgical extirpation is still the
treatment of choice for nerve sheath tumours and recurrence is uncommon. Efforts should be
made to preserve unaffected structures and patients should be counseled preoperatively on
the possible high risk of morbidity especially in the elderly group where close follow up and
aggressive rehabilitation should be instituted following surgery.
Keywords: Cervical schwannoma, vagus nerve, neurogenic tumour; parapharyngeal space
The head and neck region is a source of swellings of various types of pathology. Nonetheless,
neurogenic tumours arising from these regions are uncommon in the adult population and are
rare in the pediatric group. On the other hand, these tumours are commonly found arising from
the parapharyngeal spaces.1 The reported sites of origin of neurogenic tumours are the cranial
nerves 9-12, the sympathetic chains, the cervical plexus and the brachial plexus.2-5 Cervical
schwannomas are rare, slow-growing tumours of nerve sheath origin that may originate from
any of these nerves.6 They are also commonly referred as neuromas and neurilemmomas. They
are usually asymptomatic benign lesions and complete surgical resection is the treatment of
choice. Malignant transformation is unusual. No gender predilection is noted and they are usually
reported to occur in patients between 34 and 67 years of age.6 We report the case of a patient
diagnosed with cervical schwannoma of vagal nerve origin, which is rare.
Cervical Vagal SchwannomaDoh Jeing Yong, MBBS, MRCS1
Iskandar Hailani, MBBS, MS (ORL-HNS)1
Mohd Razif bin Mohamad Yunus, MBBS, MS (ORL-HNS)2
1Department of Otorhinolaryngology
Hospital Kuala Lumpur, Malaysia
2Department of Otorhinolaryngology
Universiti Kebangsaan Malaysia Medical Centre
Kuala Lumpur, Malaysia
Correspondence: Doh Jeing Yong, MBBS, MRCS
Department of Otorhinolaryngology,
Hospital Kuala Lumpur, Jalan Pahang, 50586
Kuala Lumpur, Malaysia
Phone: +60122719921
Fax : +60326916725
Email: drdjyong@gmail.com
Reprints will not be available from the authors.
The authors declared that this represents original material
that is not being considered for publication or has not been
published or accepted for publication elsewhere, in full or in
part, in print or electronic media; that the manuscript has been
read and approved by all the authors, that the requirements
for authorship have been met by each author, and that each
author believes that the manuscript represents honest work.
Disclosures: The authors signed disclosures that there are no
financial or other (including personal) relationships, intellectual
passion, political or religious beliefs, and institutional affiliations
that might lead to a conflict of interest.
Philipp J Otolaryngol Head Neck Surg 2010; 25 (2): 23-26 c Philippine Society of Otolaryngology – Head and Neck Surgery, Inc.
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 25 no. 2 July – december 2010
CASE REPORTS
24 PhiliPPine Journal of otolaryngology-head and neck Surgery
CASE REPORT
A 65-year-old lady with painless swelling on the right side of the
neck for 15 years consulted at our centre for recent enlargement. She
had no dysphagia, dyspnoea or other associated symptoms nor was
there a past history of cervical trauma. Her past medical and surgical
histories were unremarkable. On examination, the swelling was oval in
shape and situated beneath the upper and middle third of the right
sternocleidomastoid muscle. It measured 5 x 3 cm with normal overlying
skin. On palpation, the mass was firm in consistency, pulsatile and could
be displaced from side to side but not up and down. No bruit was noted
on auscultation. Regional lymph nodes were not enlarged. The intraoral,
indirect laryngeal and post nasal mirror examinations were normal.
No cranial nerve deficits or Horner’s syndrome were noted. Flexible
nasopharyngolaryngoscopy showed no significant findings. In view
of the pulsatility of the neck mass, contrasted computed tomography
scan (CT) of the neck was performed and revealed a well circumscribed
non-enhancing heterogenous mass measuring 4x4x7cm over the right
side of the neck. It extended from below the mandible to the level
above the cricoid cartilage. The mass splayed the right internal jugular
vein and right common carotid artery. The patient was diagnosed with
neurogenic tumour and underwent surgical extirpation via a transverse
right cervical skin incision. All great vessels were isolated and controlled
before the mass was excised. Intraoperatively, the tumour was tracked
to the vagal nerve in origin and separated en-bloc from the vagal trunk.
The glossopharyngeal, hypoglossal, lingual, accessory nerves were all
preserved. The patient was transferred to the intensive care unit after
the operation. Laryngeal functions were noted to be normal. During
the early postoperative period, the patient developed pneumonia
and the neck wound was complicated with an expanding hematoma
despite a functioning surgical drain in-situ. The patient underwent a
second surgery for wound exploration, hemostasis and hematoma
removal after which she was readmitted to the intensive care unit but
was not recuperating well. She was kept ventilated and unfortunately
succumbed to sepsis secondary to pneumonia one week after surgery.
The resected specimen reported findings that were consistent with
typical features of schwannoma.
DISCUSSION
Schwannomas are rare, benign tumours of nerve sheath origin that
may originate from any of the cranial, peripheral or autonomic nerves.1
Over the last few decades, much literature has been written on the
studies on intracranial schwannoma with regards vestibular neuroma.
Nonetheless, a majority of schwannomas are non-vestibular and
extracranial. Kang et al. reported merely 6 cases of vagal schwannoma
identified over the period of 10 years retrospective study.6
Extracranial non-vestibular head and neck schwannomas usually
present as asymptomatic, slow-growing lateral neck masses that can
be palpated along the medial border of the sternocleidomastoid
muscle. This renders preoperative diagnosis difficult as many vagal
schwannomas do not present with any neurological deficits.5 Therefore,
possible differentials include metastatic cervical lymphadenopathy,
malignant lymphoma, carotid body tumour, branchial cyst, as well
as aneurysm. When symptoms are present, hoarseness is the most
common symptom for vagal schwannomas. Occasional palpation of
the mass may induce paroxysmal coughing.8 Horner’s syndrome may
prevail when the tumour has pressured on the cervical sympathetic
chains, or when these chains are themselves the origin of the tumour.
Imaging studies play an important role in the diagnosis of head and
neck schwannomas. Regardless of the nerve of origin, schwannomas
in general are hypodense in relation to muscle tissue on CT without
contrast. With contrast, these lesions may show some degree of
enhancement, often peripheral.13 More contrast-enhancing lesions
should merit differentials of possible vascular lesions. In such instances,
angiography or magnetic resonance angiography may be employed
to outline the feeding vessels and preoperative embolization could
be planned. According to Lin et al.1 the site and the way the major
neck vessels are displaced could give further clues on the type of
schwannoma. Vagal schwannomas typically separate the internal
jugular vein and carotid arteries but do not usually widen the carotid
bifurcation. On the contrary, sympathetic chain schwannomas mildly
splay the carotid bifurcation but do not separate the great vessels. The
splaying of the carotid bifurcation is usually more prominent in carotid
body tumours. This is called the “lyre sign,” which, along with significant
contrast enhancement, is rarely associated with schwannoma.14
Differentiating amongst the origin of schwannoma can be
challenging. In one study, the sympathetic chain was shown to be the
most usual site of origin for parapharyngeal schwannoma.4 Meanwhile,
Maniglia et al. stated that the vagus nerve is the site of origin in
approximately 50% of cases.10 The identification of the exact nerve
trunk from which the schwannoma arises can be difficult to ascertain.
Anatomic evaluation by direct vision intraoperatively is an acceptable
way but may not be feasible in all cases. Otherwise, the derivation
may be presumed based on the presenting features or postoperative
morbidity experienced by the patient.3 Nonetheless, adjacent nerves
could also be damaged during surgical extirpation, resulting in error
of the assumption of origin. Therefore, some diagnoses of the site of
origin of schwannoma are definitive; others, presumptive.15
Histologically, on hematoxylin and eosin staining, schwannomas
show typical clusters of alternating areas of compact hypercellular with
spindle shape cells (Antoni A) with areas of loose hypocellular patterns
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 25 no. 2 July – december 2010
CASE REPORTS
PhiliPPine Journal of otolaryngology-head and neck Surgery 25
(Antoni B). Furthermore, schwannomas also show positivity in S100
protein immunohistochemical studies. Although neurofibromas are
of schwann cell origin, they are differentiated from schwannomas by
their lack of true capsules and presence of only loose interlacing bands
of spindle cells. Moreover, the nerve fibers seen in neurofibromas
are found scattered throughout the tumour body whereas those of
schwannomas are compressed to one side.
Treatment of vagal schwannomas should encompass complete
surgical extirpation with preservation of the neural pathway, as in
this case. If the plane of resection is inadequate and preservation is
technically difficult, the involved segment of the nerve trunk may
be resected with an end-to-end anastomosis using microsurgical
techniques. Invariably, this type of procedure will result in vocal
cord paralysis or paresis. Therefore, aggressive voice and speech
rehabilitation should entail after the surgery.
Morbidities are not uncommon after surgical resection of
extracranial nerve sheath tumours. Biswas et al.16 reported high
complications rates of surgery on benign extracranial nerve sheath
tumours. Complications like dysphagia, dysphonia, Horner’s syndrome,
facial myotonia, hypoglossal palsy, facial palsy and keloid formations
have been reported.14-15 Nonetheless, neural complications could occur
as a result of tumour compression. Therefore there is a need for relevant
head and neck neural assessment prior to the surgery so as to correctly
identify post-operative neural morbidity. Vascular complications have
Figure 1. Preoperative appearance of the pulsatile right cervical lesion
Figure 2. Contrast Computed Tomography of the neck, coronal section: Well-circumscribed
dumbbell-shaped heterogenous density in the right parapharyngeal region splaying the right
internal jugular vein (dotted arrow) and right carotid artery (solid arrow)
Figure 3. Histopathology (H&E stain 40X) of resected specimen revealed typical benign looking
spindle-shape cells arranging themselves in alternating rows of compact hypercellularity and
loose hypocellularity, commonly referred to as Antoni Cells A (Black Circle) and Antoni Cells B
(White Circle) respectively. Courtesy of Dr Suryati Yusof, Senior Neuropathologist Hospital Kuala
Lumpur (Slide No 9076/2009)
(Hematoxylin - Eosin, 40X)
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 25 no. 2 July – december 2010
26 PhiliPPine Journal of otolaryngology-head and neck Surgery
CASE REPORTS
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also been reported and are common after intracranial schwannoma
resection17 but rare for extracranial schwannomas. Rapidly forming
hematoma in a neck surgical wound is a dreadful complication and
should merit immediate intervention. Tracheostomy may be needed if
the airway is compromised. Post surgery atelectasis of the lung is usually
the main cause of pneumonia and aggressive chest physiotherapy
should be instituted both pre and post operation. Pneumonia may also
occur as a result of aspiration secondary to vocal cord palsy possibly
due to direct trauma to vagal trunk, traction injury or even compression
from hematoma. Because initial laryngeal functions were noted to be
normal after the tumour resection in this case, the subsequent wound
hematoma could have compressed on the preserved vagal trunk and
precipitated aspiration pneumonia.
In conclusion, a patient presenting with solitary mass in the neck
should raise the alarm of possible nerve sheath tumour and in the
setting of parapharyngeal space involvement, the possibility of arising
from cranial nerves, brachial plexus, cervical sympathetic chains or
major peripheral nerves. Every effort should be made to preserve the
nerve of origin and the patient should be counseled preoperatively on
the risk of morbidity especially in the elderly group. Intervention was
needed in this case in view of the rapid enlargement of the cervical
swelling that could signify malignant transformation or anticipated
compressive symptoms. Surgical extirpation is still the treatment of
choice for nerve sheath tumours and tumour recurrence is uncommon.
Nonetheless, in view of the possible surgical morbidities, close follow
up and aggressive rehabilitation should be instituted following surgical
treatment.