Schwannoma of accessory nerve: A differential of neck swellings

Abstract

Introduction:Intracranial schwannomas comprise approximately 8% of primary intracranial tumours, and more than 90% of intracranial schwannomas originate from vestibular nerves. Schwannomas originating from non-vestibular cranial nerves are very rare, particularly arising from accessory nerve. Accessory nerve schwannomas constitute only 6.66% of all non-vestibular intracranial schwannomas. The most recent substantial review of literature reports only 44 total cases of accessory nerve schwannoma. Case Report: We report a rare case of right accessory nerve schwannoma in a young male (genetic predisposition-unknown), not associated with neural deficit, presented with visible neck swelling and discomfort, assessed clinically and evaluated by CT scan, managed by surgical resection without residual weakness of muscle, diagnosis confirmed by histopathological examination. Discussion: Schwannomas, arising from accessory nerve, are relatively uncommon, and only a few of cases have been reported so far. Patients with accessory nerve schwannoma locating in extracranial site present with a gradually increasing neck mass that draw less attention. It is challenging for surgeons on how to evaluate extracranial/cervical spinal accessory nerve schwannomas by radiography. However, it is insensitive to make a definite diagnosis for schwannoma, and to identify the nerve origins of tumours. Enhanced CT scans can help us to diagnose schwannomas. Conclusion: Though a rare diagnosis, peripheral nerve Schwannoma should be included in differential diagnosis of neck swellings having ruled out other conditions, easily evaluated by CT/MRI and successfully managed by surgical resection.