CNS tumor
Meningeal tumors
WHO grading of meningiomas

Author: Jesse Kresak, M.D. (see Authors page)
Editor: Anthony T. Yachnis, M.D.

Revised: 5 September 2017, last major update December 2014

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: WHO grading of meningiomas [title]

Table of Contents
Definition / general
Cite this page: Kresak, J. WHO grading of meningiomas. PathologyOutlines.com website. http://pathologyoutlines.com/topic/cnstumorwhomeningioma.html. Accessed October 23rd, 2017.
Definition / general
  • WHO grades meningiomas on a scale from I to III (Louis: WHO Classification of Tumours of the Central Nervous System, 4th Edition, 2007)
  • Majority of meningiomas are WHO grade I
  • Grades by subtype
    • Grade I:
      • Meningothelial
      • Fibrous (fibroblastic)
      • Microcystic
      • Transitional
      • Psammomatous
      • Angiomatous (includes hemangioblastic, angioblastic)
      • Secretory subtypes
      • Metaplastic
      • Lymphoplasmacyte rich
    • Grade II:
      • Clear cell and chordoid subtypes or atypical by criteria
    • Grade III:
      • Rhabdoid and papillary subtypes or anaplastic by criteria

  • Criteria for atypical meningioma, WHO grade II (5 - 15% of all meningiomas)
    • 4 - 19 mitotic figures/10 HPF OR
    • Brain invasion OR
    • Three of these histologic features:
      • Increased cellularity
      • Small cells with high N/C ratio
      • Large and prominent nucleoli
      • Patternless or sheet-like growth
      • Foci of "spontaneous" or geographic necrosis

  • Criteria for anaplastic meningioma, WHO grade III (1 - 2% of all meningiomas)
    • Either 20 or more mitotic figures/10 HPF OR
    • Display frank sarcomatous or carcinomatous histology
  • Note:
    • Invasion of dura, bone or soft tissue does not affect grading
    • Pleomorphic or atypical nuclei do not affect grade
    • Ki67 is not a true diagnostic criteria, however it is usually greater than 4% and up to 20%