|Year : 2021 | Volume
| Issue : 2 | Page : 163-166
A middle ear paraganglioma masquerading as a facial nerve schwannoma
Reshma Raj1, Naresh Panda1, Ramya Rathore1, Gyanranjan Nayak2, Debajyoti Chatterjee3
1 Department of Head and Neck Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Otolaryngology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
3 Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
|Date of Submission||04-Aug-2021|
|Date of Decision||13-Aug-2021|
|Date of Acceptance||15-Aug-2021|
|Date of Web Publication||17-Dec-2021|
Dr. Naresh Panda
Department of Otolaryngology Head and Neck Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh
Source of Support: None, Conflict of Interest: None
We report the rare case of a 36-year-old female with complaints of unilateral facial weakness and hearing loss with clinical, imaging, and intraoperative findings suggestive of facial nerve schwannoma, but the postoperative histopathology report was consistent with paraganglioma (PGL). After a primary excision, the patients developed recurrence and was accordingly managed by surgical excision again.
Keywords: Facial nerve palsy, facial neve schwannoma, paraganglioma, recurrence
|How to cite this article:|
Raj R, Panda N, Rathore R, Nayak G, Chatterjee D. A middle ear paraganglioma masquerading as a facial nerve schwannoma. J Head Neck Physicians Surg 2021;9:163-6
|How to cite this URL:|
Raj R, Panda N, Rathore R, Nayak G, Chatterjee D. A middle ear paraganglioma masquerading as a facial nerve schwannoma. J Head Neck Physicians Surg [serial online] 2021 [cited 2022 May 17];9:163-6. Available from: https://www.jhnps.org/text.asp?2021/9/2/163/332719
| Introduction|| |
Paragangliomas (PGLs) are slow-growing, benign lesions which follow an indolent course. Of all the PGLs in the body, approximately 3% occurs in the head-and-neck region. Glomus tumors are also known by the name chemodectomas or nonchromaffin PGLs arising from chemoreceptors of neural crest cells. Among the head and neck PGLs, the most common is the carotid body tumor followed by glomus jugulare, glomus vagale, and the glomus tympanicum. PGLs arising from the facial nerve (FN) are a rare cause of FN paralysis and are often thought to be of nonneoplastic origin like schwannoma, meningioma, or middle ear adenoma. We are reporting a rare case of PGL arising in close proximity to the main FN trunk presenting initially with FN palsy mimicking a schwannoma.
| Case Report|| |
A 36-year-old female presented with a 9-month history of progressive right-sided facial weakness, associated with hearing loss. She had no complaints of tinnitus, vertigo, or ear discharge from the ear. Examination revealed House-Brackmann (HB) grade VI right facial palsy. On otoendoscopy, there was a smooth reddish bulge in posterosuperior quadrant of right bony external auditory canal (EAC) obscuring the view of the tympanic membrane. The patient was evaluated with the probable differential diagnoses of FN schwannoma, hemangioma, cholesteatoma, and glomus jugulo tympanicum. An audiogram showed grossly normal hearing from 250 Hz to 8000 Hz in both the ears. Radiological investigations included a magnetic resonance imaging (MRI) and computed tomography (CT). A contrast enhanced MRI(CEMRI) of the brain revealed a moderately enhancing T1 weighted hyperintense lesion measuring 1.3 cm × 1.7 cm × 1.7 cm in the right jugular foramen abutting the right internal jugular vein. High-resolution CT (HRCT) of the temporal bone revealed a lobulated lesion in the posterior mesotympanum of right temporal bone eroding the jugular foramen, facial canal with encasement of vertical segment of the FN, and enlargement of the stylomastoid foramen [Figure 1]. All the above findings strongly pointed toward the diagnosis of FN schwannoma. Subsequently, the patient underwent transmastoid excision of the mass in 2014 with intraoperative findings of 1 cm × 2 cm bleeding mass which was seen arising from the vertical segment of the FN lying in the posterior mesotympanum, extending into the EAC, by eroding the posterior canal wall. The mass was also extending up to the attic and inferiorly reaching till the hypotympanum. A cable graft was harvested from the greater auricular nerve and end-to-end anastomosis was performed. The entire mass was removed in toto and sent for histopathological examination (HPE). The postoperative report showed classic pattern of cells arranged in the form of nests separated by fibrovascular core with cytoplasmic positivity for synaptophysin pointing toward the diagnosis of PGL. She was on regular follow up with a persistent HB grade VI FN palsy despite nerve repair. After 2 years of the initial surgery, she underwent facial reanimation surgery in the form of temporalis transfer for her facial palsy. Two years later, she presented with progressive complaints of pulsatile tinnitus in the right ear associated with ear discharge, impaired hearing and persistent FN palsy. MRI and CT at this stage revealed recurrent disease. MRI of the brain showed heterogeneously enhancing lesion in the right jugular foramen of size 3 cm × 2.7 cm × 2.8 cm extending into the right middle ear cavity. HRCT temporal bone showed mildly enhancing lesion of size 3.4 cm × 2.4 cm × 2.3 cm in the right jugular foramen with expansion of the jugular foramen with extension into the carotid space, intracranial extension into the cerebellopontine angle [Figure 2]. A pure-tone audiogram showed moderate mixed hearing loss at 4000-8000 Hz in the right ear. The 24 h urine for epinephrine and urinary Vanillyl Mandelic acid was normal. She underwent revision transmastoid excision of the tumor along with tarsorrhaphy of the right eyelids. The intraoperative finding of the procedure was reddish vascular smooth circumscribed lobulated mass arising from the right FN main trunk in the region of stylomastoid foramen extending to the middle ear, mastoid and laterally pushing the sigmoid sinus [Figure 3]. The postoperative MR scan showed a small residual tumor closure to the posterior fossa.[Figure 4] and [Figure 5] Once again, the postoperative HPE report was consistent with PGL which showed tumor arranged in islands separated by vascular channels and tumor cells show abundant eosinophilic granular cytoplasm and stippled chromatin with ki67 proliferation index of 1%–2% revealing the benign nature of the tumor [Figure 6]. Postoperatively, the patient was discharged in a satisfactory condition.
|Figure 1: Imaging before first surgery. (a) Axial contrast-enhanced magnetic resonance imaging showing T1 hyperintense lesion in right jugular foramen. (b) Axial computed tomography scan shows lobulated lesion eroding the right jugular foramen with enlargement of stylomastoid foramen. (Black arrow-stylomastoid foramen)|
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|Figure 2: Imaging before the second surgery. (a) Axial contrast-enhanced magnetic resonance imaging show hyperintense lesion in jugular foramen. (b) Axial T showing expansion of the jugular foramen with extension into cerebellopontine angle|
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|Figure 3: Intra-operative image. (a) Tumor arising from the facial nerve trunk. (Black arrow is showing the facial nerve trunk)|
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|Figure 4: Magnetic resonance imaging before the second surgery showing the lesion in the jugular foramen abutting the posterior fossa|
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|Figure 5: Post operative magnetic resonance imaging showing a residual tumor towards the posterior fossa|
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|Figure 6: Histopathology of facial nerve paraganglioma. (a) Section shows a tumor arranged in islands separated by vascular channels S (H and E, ×100). (b) Tumor cells show abundant eosinophilic granular cytoplasm and stippled chromatin (H and E, ×100). Video smooth circumscribed lobulated mass arising from the facial nerve trunk was removed in toto|
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| Discussion|| |
Glomus jugulo tympanicum is one of the most common benign neoplasms of the middle ear arising from the dome of the jugular bulb. PGLs are most common in females, with female-to-male ratio of 3:1. It is common in the fifth decade. Out of all the PGLs, 10% occur in extra-adrenal sites and studies have shown that the incidence of head and neck PGLs is 1 in 30,000 of all head-and-neck tumors. They are rarely functional (<1%) due to lack of the enzyme phenylethanolamine N-methyltransferase. PGL of the FN is an extremely rare presentation. A study by Guild et al. showed that at least 1 branch of Arnold nerve ascends from jugular bulb through facial canal through the mastoid canaliculi and the presence of paraganglia along this distribution could be the reason for origin of PGL from the FN. Unilateral FN dysfunction is the most common presenting symptom in case of FN PGL followed by pulsatile tinnitus.
Patients with glomus jugulotympanicum usually present with hearing loss, pulsatile tinnitus, and lower cranial nerve neuropathy. On otoendoscopy, a reddish pulsatile mass is seen behind an intact tympanic membrane. On the contrary, the FN sheath tumors have fluctuating FN paresis rather than progressive and complete palsy. They also have male predominance and are commonly seen in the 5th decade. They classically present with recurrent lower motor neuron FN palsy with hearing impairment. Schwannomas can occur in any segment of the FN with geniculate ganglion being the most common site. The diagnosis of FN schwannoma was considered the primary diagnosis because the patient's initial complaints were only FN weakness and impaired hearing, with no complaints of blood stained discharge from the ear, pulsatile tinnitus, vertigo or otalgia.
The characteristic findings of schwannoma on MRI are an enhancing dumbbell-shaped lesion on T1-weighted imaging and on CT it shows a soft-tissue mass in the tympanum bound by a thin rim of bone. In T1-weighted MRI, PGL has a classic “salt and pepper” appearance. On CT imaging, PGL in contrast to schwannoma has classical “moth-eaten” pattern of bony destruction. In case of glomus jugulotympanicum, CEMRI of the brain shows an enhancing mass dorsal to right jugular vein as it courses through the jugular foramen of the skull base. Since the findings in our case were an hyperintense lesion in the jugular foramen our primary diagnosis was narrowed down to glomus jugulotympanicum.
Surgical excision with FN reconstruction is the best option for the above-mentioned tumors. The intraoperative findings in a glomus jugulotympanicum are usually a reddish pulsatile mass arising from the jugular bulb which is delineated carefully to avoid unwanted bleeding. On the contrary, the FN PGLs have a reddish shiny appearance in the region of the fallopian canal extending into the mastoid cells, sparing the jugular foramen. Glomus jugulotympanicum and FN PGL usually derive their blood supply from the ascending pharyngeal artery. In a case of schwannoma arising from the FN, there could be a cystic mass with a dark hue near the stylomastoid foramen. Nerve grafting is usually done with greater auricular nerve as the first choice followed by the sural nerve. In a case of PGLs, the various treatment options are surgical excision and radiotherapy, both of which were offered to our patient. She opted for the former.
The histological features of the two entities are quite different and it often clinches the diagnosis. PGLs show a classical picture of Zellballen pattern in which Type I cells contributed by the chief cells which is surrounded by Type II sustentacular cells. Type I cells are positive for chromogranin A and synaptophysin. Type II cells stain positive for S-100. The tumor consist of angiocentric uniform sheets of cells with oval nuclei, forming a perivascular “collar” around vessels. On the other hand, the histopathology of schwannoma usually comprises of cellular Antoni A areas alternating with hypocellular Antoni B areas. Antoni A areas are composed of interlacing bundles of spindle cells (Schwann cells) with wavy or oval nuclei, eosinophilic cytoplasm, and indistinct cytoplasmic borders.
Contrera et al. showed that PGLs of the head and neck have a recurrence rate of 2.92% and a metastatic rate of 3%. There is a 10% chance of recurrence if we subject the patient to reimaging every 3.4 years after treatment. The probability of recurrence increases with involvement of the FN.
To conclude, though rare, the possibility of FN PGL should be thought as a differential diagnosis, particularly in a case of isolated facial palsy associated with tinnitus. The excision of the tumor with FN reconstruction is the mainstay of treatment for FN PGLs.
This material has never been published and is not currently under the evaluation in any other peer-reviewed publication.
Ethical approval was not necessary in the preparation of this article.
Patient consent for participation
Written informed consent was taken from the patients' parents at the every step of investigation and treatment as per the protocol.
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Consent was taken for the use of patient's treatment-related data and images for academic use and publication on the condition of anonymity.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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