[A case of intracranial hypoglossal neurinoma].

A case of intracranial hypoglossal neurinoma was reported and the literature was reviewed. A 56-year-old female with a three month history of urinary incontinence, headache and gait disturbance was admitted to our hospital in April, 1986. General physical examination revealed nothing remarkable. Café au lait spot was not found. Neurological examination revealed horizontal gaze nystagmus toward the right, paresthesia of the left upper extremity and mild muscle weakness of the left upper and lower extremities. Atrophy of the right side of the tongue with fasciculation was also noted. Computed tomography (plain, enhanced and metrizamide cisternography) demonstrated no obvious findings of a mass in the posterior fossa. Anterior-posterior view of skull tomography showed enlargement of the right hypoglossal canal. MRI in short spin echo demonstrated a low intensity mass at the foramen magnum on the right side, which compressed the medulla oblongata. Vertebral angiography demonstrated a hypovascular extra-axial mass with right posterior inferior cerebellar artery displacement. On May 1986, suboccipitocranioectomy was performed. The intracranial tumor which arose from the right hypoglossal nerve was removed, but the extracranial portion of the tumor was left unremoved. Histological diagnosis was neurinoma. Post-operative course was uneventful. Intracranial hypoglossal neurinoma are rare and our case marks the 38th reported case. Hypoglossal nerve palsy is the most important symptom and the enlargement of the hypoglossal canal shown by skull tomography or CT for bone images is the most frequent neuroradiological findings. Plain, enhanced CT and metrizamide CT have been discussed as very useful means to detect this lesion.(ABSTRACT TRUNCATED AT 250 WORDS)