title: Schwannoma of the spinal accessory nerve in the cisterna magna.
abstract: BACKGROUND
  Intracranial schwannoma of the accessory nerve can be divided into two types. One is a jugular foramen type arising from the accessory nerve of the jugular foramen, while the other is an intracisternal type, which arises from the spinal root of the accessory nerve and is separate from the jugular foramen. The latter type is rare, and only 9 cases have been reported previously.
  
  
  METHODS
  A 46-year-old female presented with a large, midline mass lesion in the posterior fossa manifesting as foramen magnum syndrome. Magnetic resonance imaging (MRI) revealed a huge tumor with cystic lesion located in the cisterna magna with extension to the C1 spinal level. The tumor was totally removed by a suboccipital craniectomy and C1 laminectomy. It originated from the spinal root of the right accessory nerve. Temporary slight atrophy of the right sternocleidomastoid muscle was observed, but the patient was free of disease 2 years after treatment.
  
  
  CONCLUSIONS
  We report a schwannoma of the spinal accessory nerve in the cisterna magna. The clinical and neuroradiological findings are discussed with a review of the literature. The initial symptoms were variable without loss of function of the cranial nerve, and the tumor tended to grow in the cisterna magna without laterality. Because of the absence of typical neurologic symptoms, early neuroradiological investigation by MRI is recommended for accurate diagnosis of these tumors.
authors.affiliation: Department of Neurosurgery, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Tatebayashi
authors.forename: Yasuakira
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hideharu
authors.initials: H
authors.lastname: Numata
authors.forename: Shin
authors.initials: S
authors.lastname: Kawakami
authors.forename: Hideki
authors.initials: H
authors.lastname: Kamitani
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D020436:Accessory Nerve Diseases / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D002946:Cisterna Magna / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D003390:Cranial Nerve Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009442:Neurilemmoma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed