CNS tumor
Meningeal tumors
Anaplastic meningioma

Author: Jesse Kresak, M.D. (see Authors page)
Editor: Maria Martinez-Lage, M.D.

Revised: 20 September 2016, last major update September 2016

Copyright: (c) 2005-2016,, Inc.

PubMed Search: Anaplastic meningioma [title]

Cite this page: Anaplastic meningioma. website. Accessed August 21st, 2017.
Definition / general
  • WHO 2016 definition: A meningioma that exhibits overtly malignant cytology (resembling that of carcinoma, melanoma, or high grade sarcoma) and/or markedly elevated mitotic activity
  • Grade III
  • Also called malignant meningioma
  • 1-3% of meningiomas
  • Either denovo, associated with recurrent tumors or associated with prior radiation (J Neurooncol 2005;74:195, Med Pediatr Oncol 1995;24:265)
  • Associated with aberrant CpG island hypermethylation profile (Hum Pathol 2005;36:416)
  • Occasional metastases beyond the CNS (Clin Neurol Neurosurg 2011 Sep;113:592)
  • Recurrence rates are 50-94%, and overall survival is estimated to be 2-5 years
Radiology description
  • MRI may show irregular tumor borders, heterogenous tumoral enhancement, and peritumoral edema suggesting a high grade meningioma
Radiology images
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Very large bifrontal extraaxial mass

Gross description
  • Dural based
  • May be well circumscribed or readily adherent to brain parenchyma
  • Size can vary widely
  • Gross necrosis can be present
Microscopic (histologic) description
  • Criteria to be termed anaplastic are either 20+ mitotic figures/10 HPF or displaying frank malignant, sarcomatous or carcinomatous histology
  • Most also show extensive necrosis
  • Variable invasion of brain
  • Proving meningothelial origin can be challenging
Microscopic (histologic) images
Flickr images, courtesy of Jesse Kresak, M.D.:
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Abundant mitoses

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Anaplastic foci

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Meningothelial-like cells

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H&E, keratin

Cytology images
Flickr images, courtesy of Jesse Kresak, M.D.:
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Squash prep

Positive stains
Negative stains
Molecular / cytogenetics description
  • Loss of 6q, 9p, 10 and 14q
  • Gains of 1q, 9q, 15q, 17q, 20q
  • Deletion of 1p21, which includes CDKN2A
  • NF2 mutation in 70% of cases
  • TERT promoter mutations in 20% of cases (J Natl Cancer Inst 2015 Dec 13;108(5))
Differential diagnosis