Accessory Nerve Schwannomas Presenting with Hypoglossal Nerve Palsy: A Narrative Review with an Illustrative Case

Background: Intracranial accessory nerve schwannomas involving the jugular foramen are rare tumors with heterogeneous clinical presentations. Although lower cranial nerve dysfunction is common, hypoglossal nerve palsy is uncommon and may obscure identification of the nerve of origin. Methods: A narrative review of the literature was conducted to identify reported cases from 1961 to December 2025. Clinical manifestations were categorized as initial and preoperative symptoms, and their temporal evolution was analyzed according to tumor location. Imaging findings, surgical management, and neurological outcomes were reviewed. An illustrative case with hypoglossal nerve palsy was included. Results: A total of 58 cases, including the present case, were identified. According to the Julow classification, 38 tumors were intracisternal and 20 were intrajugular. Intracisternal tumors predominantly caused posterior fossa compression symptoms, whereas intrajugular tumors more frequently showed lower cranial nerve dysfunction. Hypoglossal nerve palsy was observed in seven cases, including three as the initial symptom, and occurred mainly in intrajugular tumors. Imaging commonly demonstrated jugular foramen enlargement and, in selected cases, continuity with enlargement of the extracranial hypoglossal canal. Surgical treatment was associated with improvement or stabilization of hypoglossal nerve function in all reported cases. Conclusions: Accessory nerve schwannomas may occasionally present with hypoglossal nerve palsy, most likely due to secondary compression. Careful assessment of symptom progression and skull base imaging may improve preoperative diagnosis and surgical planning.