[A case of accessory nerve neurinoma presenting an intracisternal tumor].

A case of neurinoma from the spinal accessory nerve which is located in the cisterna magna is reported. A 54-year-old woman was admitted to the institute in 1990 with complaints of headache, nausea and ataxic gait for several months. Plain CT showed dilation of the lateral ventricles and a mass of lower density in the cisterna magna. The capsule and septa of the mass were enhanced with contrast medium. MRI showed the mass was low intense on T1-weighted images and high intense on T2-weighted images. Gadolinium visualized the mass multicystic. V-P shunt was performed before tumor resection. Through suboccipital craniectomy and C1 laminectomy the tumor was removed. The tumor had a long neck attached to the right spinal accessory nerve and extended to the cisterna magna.