Intracisternal schwannoma of the spinal accessory nerve presenting as a normal pressure hydrocephalus syndrome. Case report and review of the literature.

Schwannomas of the spinal accessory nerve are rare lesions. They can be characterized by their locations as either intrajugular or intracisternal schwannomas, most of them being intrajugular. Only five cases arising in the cisterna magna are reported in literature. Clinical symptoms generally consist of 11th cranial nerve palsy associated with cerebellar signs and myelopathy. An additional case, studied by MRI, is described. The patient showed a mild cerebellar syndrome and normal pressure hydrocephalus symptoms. He was operated on and the mass completely removed with good postoperative results. The role of MRI for diagnosis of lower cranial nerve schwannomas is stressed, even though does not detect the exact nerve of origin. Total removal of these lesions is recommended, since their benign nature and unavoidable recurrence in case of partial excision.