title: A cylindrical extracranial cranial base neurinoma of the hypoglossal nerve: a rare tumor with a rare localization: case report.
abstract: OBJECTIVE
  Neurinomas of the hypoglossal nerve are very rare. They are mostly located intracranially or combined intra- and extracranially, resulting in the so-called dumbbell shape. The isolated extracranial localization of the neurinoma of the hypoglossal nerve adjacent to the cranial base as described in this case report is extremely rare.
  
  
  METHODS
  The 23-year-old patient presented with recurring headaches. She had right-sided hypoglossal nerve palsy for approximately 5 to 6 years. Magnetic resonance imaging revealed an extracranial tumor with contact to the cranial base originating from the hypoglossal nerve.
  
  
  METHODS
  The tumor was extirpated surgically and verified histologically as a schwannoma of the hypoglossal nerve.
  
  
  CONCLUSIONS
  Pathologies of the hypoglossal nerve as such are very rare within the clinical landscape. When a tumor occurs, its shape and location must be analyzed to establish whether, or by which approach, surgical removal is feasible. Although very unusual, the mere extracranial occurrence of a hypoglossal neurinoma at the cranial base should be considered a differential diagnosis.
authors: Department of Neurosurgery, Heinrich-Heine University, Düsseldorf, Germany. Hi-Jae.Heiroth@uniduesseldorf.de
authors: Hi-Jae
authors: HJ
authors: Heiroth
authors: Markus J
authors: MJ
authors: Riemenschneider
authors: Hans-Jakob
authors: HJ
authors: Steiger
authors: Daniel
authors: D
authors: Hänggi
mesh_terms: D003390:Cranial Nerve Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D020437:Hypoglossal Nerve Diseases / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D009442:Neurilemmoma / Q000473:pathology* / Q000601:surgery; D009418:S100 Proteins / Q000378:metabolism; D055815:Young Adult
chemical_list: D009418:S100 Proteins