title: Expanded Endoscopic Transclival Approach for Resection of a Chordoid Meningioma without Dural Attachment (MWODA) Located in the Prepontine Cistern.
abstract: BACKGROUND
  Meningiomas without dural attachment (MWODA) located in the posterior fossa are an unfrequent entity. They are usually located in the fourth ventricle, and their occurrence outside of this anatomic structure is an even more uncommon finding. Chordoid meningiomas are a rare subtype of meningioma, and they have been reported to account for 0.5%-1% of all meningiomas.
  
  
  METHODS
  We report the unusual case of a 36-year-old female patient, with unremarkable past medical history, who presented at our institution complaining of acute binocular diplopia. Right cranial nerve VI paresis was observed on physical examination. Imaging studies revealed an intradural retroclival solid mass that enhanced homogeneously after contrast administration. Interestingly, no dural tail was present. Expanded endonasal endoscopic resection of her retroclival lesion was performed. We used a 4-hand technique with 0 and 30 degrees endoscopes, with intradural pituitary transposition. Gross total resection was achieved and the pathology report described findings consistent with chordoid meningioma. The patient is recurrence-free and in good condition at 1-year follow-up.
  
  
  CONCLUSIONS
  We performed a thorough review of the literature, and we found 10 reported cases describing extraventricular MWODA in the posterior fossa. To our knowledge, this is the first reported case of retroclival MWODA with pathologic findings consistent with chordoid meningioma.
authors.affiliation: Department of Neurosurgery, Hospital General Universitario Gregorio Marañón, Madrid, Spain. Electronic address: lainhermesgq@gmail.com.
authors.forename: Lain Hermes
authors.initials: LH
authors.lastname: Gonzalez-Quarante
authors.affiliation: Department of Neurosurgery, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ruiz-Juretschke
authors.affiliation: Department of Neurosurgery, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Iza-Vallejo
authors.affiliation: Department of Otorhinolaryngology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Esteban
authors.initials: E
authors.lastname: Scola-Pliego
authors.affiliation: Department of Otorhinolaryngology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Poletti
authors.affiliation: Department of Neuropathology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Emma
authors.initials: E
authors.lastname: Sola Vendrell
mesh_terms: D000328:Adult; D003388:Cranial Fossa, Posterior / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008577:Meningeal Neoplasms / Q000601:surgery*; D008579:Meningioma / Q000601:surgery*; D018396:Mucin-1 / Q000378:metabolism; D044583:Neuroendoscopy / Q000379:methods*
chemical_list: D018396:Mucin-1
keywords: Chordoid; MWODA; Meningioma; Neuroendoscopy; Prepontine cistern; Transnasal pituitary transposition