A case of intracranial hypoglossal neurinoma without hypoglossal nerve palsy: operative view of the preserved rostral trunk.

Hypoglossal neurinomas usually manifest with hemiatrophy and weakness of the tongue. A rare case of intracranial hypoglossal neurinoma without preoperative hypoglossal nerve dysfunction and its operative view are presented. A 36-year-old female who presented with headaches and vertigo was admitted to our hospital. The neurological examination revealed bilateral papilledema and mild truncal ataxia, although weakness and atrophy of the tongue were not observed. Magnetic resonance and computed tomography images demonstrated a large foramen magnum tumor without enlargement of the hypoglossal canal. Total removal of the tumor was performed via a lateral suboccipital craniotomy and C1 partial laminectomy. During the operation, two trunks were observed for the hypoglossal nerve at the entrance of the hypoglossal canal. The tumor arose from the caudal trunk, while the intact rostral trunk entered the hypoglossal canal normally. The tumor only developed intracranially, and since the rostral trunk of the hypoglossal nerve was intact, the patient did not present with hypoglossal nerve palsy preoperatively.