title: Extradural en-plaque spinal meningioma with intraneural invasion.
abstract: BACKGROUND
  Extradural spinal meningiomas are rare. Our understanding of purely extradural spinal meningiomas is incomplete because most reports rarely differentiate purely extradural meningiomas from extradural meningiomas with an intradural component. Occasionally, reports have described involvement of the adjacent nerve root, but there has never been a description of an extradural meningioma that actually infiltrates the nerve root.
  
  
  METHODS
  A 42-year-old woman presented with progressive lower extremity weakness and numbness below T3 during the span of 4 months with imaging evidence of an extradural lesion compressing the cord from T4 through T6. Surgical resection revealed an extradural mass extending through the foramen at T5-6 and encompassing the cord and T5 root on the left. Pathologically, the lesion was a World Health Organization grade I meningioma with nerve root invasion and a concerning elevated mindbomb homolog 1 (MIB-1) of 9.4%.
  
  
  CONCLUSIONS
  Purely extradural meningiomas are rare, and our case is one of the first to describe a patient with an extradural meningioma that actually infiltrates the nerve root. Extradural spinal meningiomas are usually not adherent to the dura, but only appear to be adherent or invade (as in our patient) the adjacent nerve root. They are easily mistaken preoperatively and grossly intraoperatively for malignant metastatic tumors and can change the proposed surgical treatment. The long-term prognosis remains uncertain, but our patient's last follow-up suggests a favorable prognosis.
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Jayshree
authors.initials: J
authors.lastname: Tuli
authors.forename: Dan Michael
authors.initials: DM
authors.lastname: Drzymalski
authors.forename: Hart
authors.initials: H
authors.lastname: Lidov
authors.forename: Sagun
authors.initials: S
authors.lastname: Tuli
mesh_terms: D000328:Adult; D004388:Dura Mater / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007796:Laminectomy; D008279:Magnetic Resonance Imaging; D008579:Meningioma / Q000473:pathology* / Q000601:surgery*; D009460:Neurologic Examination; D011184:Postoperative Period; D011300:Preoperative Care; D013125:Spinal Neoplasms / Q000473:pathology* / Q000601:surgery*; D013126:Spinal Nerve Roots / Q000473:pathology; D013904:Thoracic Vertebrae; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: C513496:MIB1 ligase, human; D044767:Ubiquitin-Protein Ligases