Hypoglossal Neurinoma Extending Intra- and Extracranially: Case Report

Background: Hypoglossal neurinoma is very rare; our case is the 46th case.

Case Description: We report a 59-year-old woman with hypoglossal neurinoma. Her equilibrium state was disturbed due to vestibular dysfunction and she exhibited right hypoglossal palsy with glossal hemiatrophy. Computed tomography (CT) revealed a large bony erosion of the right hypoglossal canal. Magnetic resonance imaging (MRI) revealed intra- and extracranial tumor extension. There was an intracranial mass attached to the enlarged hypoglossal vertebral and posterior inferior cerebellar artery medially. The extracranial part of the mass extended along the course of the hypoglossal nerve through the enlarged hypoglossal canal. The intracranial part of the tumor was totally removed via the transcondylar approach. The diameter of the origin of the posterior interior cerebellar artery was narrow before tumor removal; it increased after surgery due to decompression. A histological diagnosis of neurilemoma was made. Her symptoms due to vestibular dysfunction disappeared postoperatively.

Conclusions: Our patient's difficulty with balance was thought to be an ischemic symptom due to circulation disturbance of the posterior inferior cerebellar artery. It disappeared after tumor removal. Surgery may be necessary later if further growth of the extracranial part of the neurinoma becomes evident.