Meningioma

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Meningioma a very common tumour in neuropathology.

General

Prevalence

  • Common.

Radiology

  • Extra-axial.

Prognosis

  • Most are benign.
    • May be malignant.

Genetics

Microscopic

Features (memory device WTC):

  • Whorled appearance - key feature.
  • Thick-walled blood vessels, usually prominent.
  • Calcification.

Many subtypes exist:

  • Atypical meningioma.
    • Has invasion of the brain - WHO Grade 2.
  • Angiomatous meningioma.
  • Others.

Images:

Notes:

  • May involute into benign sclerotic tissue.[2]

Histomorphologic grading

Grading:[3]

  • Grade 1:
    • Low mitotic rate.
    • Excludes clear cell, chordoid, papillary, and rhabdoid subtypes.
  • Grade 2 (either #1 or #2):
    1. Brain-invasive meningioma.
      • Protrusion of meningioma into brain.
        • Meninogioma with entraped GFAP +ve tissue.
    2. Atypical meningioma (by histomorphology).
      • Intermediate mitotic rate (>= 4 mitoses/10 HPF - for whatever HPF means, see HPFitis.)
      • Three of the following five features:
        1. Sheeting architecture.
        2. High NC ratio clusters; clusters of "lymphocyte-like" cells.
        3. Hypercellularity.
        4. Macronucleoli.
        5. Necrosis not caused by treatment, e.g. radiation or embolization.
  • Grade 3 (either of the following):
    • High mitotic rate (>=20 mitoses/10 HPF - for whatever HPF means, see HPFitis.)
    • "Frank anaplasia"; marked nuclear atypia.

Notes:

  • Grade II soft criteria memory device HMNs: hypercellular, macronucleoli, NC ratio increased, necrosis, sheeting.

IHC

  • EMA +ve.[4]
    • Other CKs usu. -ve.

See also

References

  1. URL: http://moon.ouhsc.edu/kfung/jty1/neurotest/Q13-Ans.htm. Accessed on: 26 October 2010.
  2. URL: http://radiographics.rsna.org/content/23/3/785.long. Accessed on: 3 November 2010.
  3. Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 194. ISBN 978-0443069826.
  4. Perry, Arie; Brat, Daniel J. (2010). Practical Surgical Neuropathology: A Diagnostic Approach: A Volume in the Pattern Recognition series (1st ed.). Churchill Livingstone. pp. 13. ISBN 978-0443069826.