CNS tumor
Meningeal tumors
Meningioma

Reviewer: Jesse Kresak, M.D. (see Reviewers page)
Editor: Anthony T. Yachnis, M.D.

Revised: 14 December 2015, last major update December 2014

Copyright: (c) 2005-2015, PathologyOutlines.com, Inc.

PubMed Search: Meningioma [title] CNS
Cite this page: Meningioma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cnstumormeningiomageneral.html. Accessed December 5th, 2016.
Definition / General
  • Most common primary brain tumor (20-30% of brain tumors, 6 per 100K annually)
  • Derive from arachnoid cap cells (associated with dura mater, choroid plexus)
  • Grow along external surface of brain or within ventricular system
  • Slow growing (may grow rapidly during pregnancy), symptoms vague or related to brain compression
  • Usually adults
  • Female predominance: 2/3 of cerebral meningiomas occur in women, 90% of spinal cord meningiomas occur in women
  • Usually solitary; multiple tumors (seen in 1-6%) are occasionally associated with neurofibromatosis 2
  • Three grades exist based on WHO criteria
    • Most are WHO Grade I (benign)
    • ~6% are WHO Grade II (increased likelihood of recurrence)
    • Rarely are WHO Grade III (malignant with metastatic potential)
  • Many variants of meningiomas exist

  • Grade I variants
    • Angiomatous:
      • 2% of all meningiomas
      • Vascular component should exceed 50% of total tumor area
      • Meningothelial cells are wrapped around small blood vessels
      • Also has large vessels
      • Mean Ki-67 index is 2%
      • Do not recur if entirely resected (Am J Surg Pathol 2004;28:390)
      • Differential diagnosis includes hemangioblastoma, which stains positive with inhibin and NSE
    • Fibroblastic:
      • Firm tumors composed of spindle cells with indistinct cell boundaries
      • Sheet-like architecture, may not contain lobules or classic meningothelial whorls
      • Resemble schwannoma or solitary fibrous tumor, but are focally EMA+, often have thick bundles of collagen
    • Meningothelial:
      • Most common variant
      • Syncytial and epithelial cells, indistinct cell borders and classic whorls
      • May have sparse psammoma bodies
    • Metaplastic:
      • May contain foci of bone, cartilage, or fat
    • Microcystic:
      • Rare to have extensive microcystic formation
      • Cells have elongated processes and loose myxoid background
      • Overall resembles microcysts
      • Has focal "classic" features
      • Variable pleomorphism
      • No cords or trabeculae, no inflammatory infiltrate
      • EM shows extracellular microcysts
    • Psammomatous:
      • Found in spinal region
      • Numerous psammoma bodies
    • Secretory:
      • Eosinophilic secretions
      • May have cytologic atypia
      • May secrete CEA
    • Transitional:
      • Meningothelial and fibroblastic features
      • Usually prominent whorls, psammoma bodies and clusters of syncytial cells

  • Grade II variants

  • Grade III variants
Radiology Description
  • Strong and homogenous enhancement on MRI with contrast
  • Usually display a "dural tail"
  • Usually isodense with the gray matter on T1-weighted MRI
  • May show a so-called "CSF crest" around the tumor indicating its extra-axial location
Case Reports
Treatment
  • Observation - if asymptomatic
  • Gross total resection is usually curative
  • Post-operative radiation if incompletely excised or WHO Grade II or III
Gross Description
  • Rounded and well circumscribed
  • Attached to dura
  • Tumor separates readily from brain
  • May grow en plaque (along dural surface) and cause reactive (hyperostotic) bone changes
Gross Images
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Tumor displaces brain without invading

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Compression of underlying cortex

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Resected tumor

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Adherent to falx cerebri

Micro Description
  • Arachnoid plane exists between meningioma and CNS parenchyma
  • Lobulated architecture, often contain "meningothelial" whorls
  • Syncytial cells with indistinct cell membranes
  • Eosinophilic cytoplasm
  • Round uniform nuclei, intranuclear pseudoinclusions common
  • May contain psammoma bodies
  • Xanthomatous degeneration, moderate nuclear pleomorphism and metaplasia may be seen but have no prognostic significance
  • Rarely necrosis or extensive hemorrhage
Micro Images

Case of the Week #373 (Angiomatous):
Smears:


Additional smears:


Frozen section:


H&E images:


Additional H&E images:


Immunostains were obtained:

BCL2

CD34


EMA


MUC1

Ki-67


p63

PASD


S100



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Angiomatous (trichrome stains)

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Fibroblastic variant

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Lipomatous variant

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Lymphoplasmacytic rich variant is CD45+



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Meningothelial variant

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Meningothelial variant

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Meningothelial-intraosseous
hyperostotic occipital



Microcystic variant:
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Lacelike pattern of fibrillary stellate cells

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Pleomorphic cells

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Pseudo-astrocytic appearance

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ProgR+ and EMA+



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Psammomatous

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Xanthomatous variant

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Xanthomatous with cholesterol
clefts and pleomorphic cells

Cytology Description
  • Small to medium sized cells with moderate well defined cytoplasm and short processes
  • Some nuclei have grooves
  • Cells form focal whorls
  • Variable psammoma bodies
Cytology Images
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Meningothelial tumor

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Whorl

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Whorl and psammoma body

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Mass at base of skull with inclusions and grooves

Positive Stains
  • Vimentin (strong), EMA (may be weak or focal, 70%), S100
  • ProgR (60-70%, usually women, tumor may grow during pregnancy)
Negative Stains
Molecular / Cytogenetics Description
  • Mutations or deletions of NF2 gene seen in sporadic meningiomas and those associated with NF2
  • Monosomy 22
Molecular / Cytogenetics Images
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Idiotype of deletion in #22

Electron Microscopy Description
  • Tightly interdigitating cellular processes held together by desmosomes