Herein, we presented a case of Vernet syndrome, also referred to as jugular foramen syndrome, caused by a cerebellopontine angle (CPA) schwannoma in a 39-year-old female. The patient was referred to the electromyography (EMG) laboratory due to right shoulder drop. Neurological examination revealed hoarseness, right shoulder drop, difficulty turning the head to the left, loss of taste in the posterior third of the tongue, and an absent gag reflex on the right side (Figure 1).
Nerve conduction studies demonstrated a significantly reduced compound muscle action potential amplitude in the right spinal accessory nerve compared to the contralateral side. Needle EMG revealed fibrillation potentials and reduced recruitment of large, polyphasic motor unit action potentials in the right trapezius muscle (Figure 2). Written informed consent was obtained from the patient. The data were evaluated in accordance with ethical standards for scientific use.
Brain magnetic resonance imaging (MRI) revealed a 42 × 22 mm lesion in the right CPA, compressing the lower cranial nerves. The mass was surgically resected, and histopathological analysis confirmed the diagnosis of schwannoma (Figure 3).
Cerebellopontine angle schwannomas involving lower cranial nerves are rare, accounting for approximately 25% of head and neck schwannomas.[1] Schwannomas typically arise from the vestibular nerve but can occasionally involve the glossopharyngeal, vagus, and spinal accessory nerves, as observed in our case. The clinical presentation can be diverse, ranging from isolated cranial nerve palsies to multiple cranial nerve deficits.[2]
This case underscored the importance of comprehensive diagnostic evaluation, particularly the role of MRI and EMG, in the assessment of lower cranial nerve lesions.[3] Electrodiagnostic studies help localize the site of neural injury and assess the extent of axonal damage. Such techniques can be used preoperatively, intraoperatively, and postoperatively to evaluate and preserve neural function. Similarly, Aydınlar et al.[4] demonstrated that intraoperative neurophysiological monitoring played a crucial role in preserving nerve function during spinal schwannoma surgery. In our case, preoperative EMG was essential for the diagnostic confirmation of the CPA schwannoma presenting with Vernet syndrome.
Surgical intervention remains the primary treatment modality; however, postoperative cranial nerve deficits may persist, as observed in our patient.[5]
We believe that this case contributed to existing literature by highlighting the diagnostic challenges and therapeutic considerations in managing Vernet syndrome associated with CPA schwannomas. Further studies are warranted to explore treatment strategies that preserve neurological function while ensuring optimal tumor control.