Facial Nerve Schwannoma Masquerading as Jugular Paraganglioma

We present the case of a 54-year-old woman who presented with right facial weakness and right-sided hearing loss and was found to have an erosive mass of the right jugular bulb. On initial examination, otomicroscopy showed a pulsating violaceous mass in the middle ear arising from the hypotympanum impinging on the tympanic membrane, and the patient had a House-Brackman II facial palsy. The audiogram demonstrated a right mild-to-moderate conductive hearing loss. The HRCT showed a right-sided irregularly shaped mass of the middle ear and mastoid encasing the tympanic and mastoid segments of the facial nerve, with moth-eaten erosion of the jugular plate. MRI T1 sequence was hypointense, T2 was isointense and T1 postcontrast showed intense enhancement of this mass. Overall, the patient’s presentation was highly concerning for jugular paraganglioma. All management options were discussed with the patient. Urine metanephrines testing was unremarkable. Genetic testing was also pursued and revealed no detectable alterations to any of the 77 paraganglioma-associated genes.

Ultimately, the patient elected to pursue surgical resection. She was referred to vascular neurosurgery for a preoperative same-day angiogram and embolization. On her angiogram, no tumoral blush or feeding arteries were identified, so no embolization was performed. Later that day she was taken for surgery, where a cortical mastoidectomy was performed. At this point tumor was seen filling the mastoid, however, the lesion was solid, tan-yellow, and well-circumscribed. This non-vascular lesion did not appear grossly consistent with paraganglioma and appeared more like schwannoma. When the nerve stimulator probe (at 0.1mA. contacted the tumor, all branches of the facial nerve activated. A piece of tumoral tissue was biopsied and sent for frozen section. This showed pathologic features including nuclear palisading (Verocay bodies), which was indeed consistent with facial nerve schwannoma. Given these findings, the decision was made to terminate the procedure to preserve facial function. The patient was seen in follow-up and found to be healing well with stable facial function. A joint plan was made to proceed with close observation and re-consider surgical resection should her facial function worsen beyond a House Brackmann 3/6. This patient represents a diagnostic dilemma–diagnostic considerations and different treatment algorithms will be presented.

 

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No conflict of interest has been declared by the author(s).

Publication History

Article published online:
05 February 2024