Difference between revisions of "Meningioma"

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**Low mitotic rate (< 4 mitoses/10 HPF - for whatever HPF means, see [[HPFitis]]).
**Low mitotic rate (< 4 mitoses/10 HPF - for whatever HPF means, see [[HPFitis]]).
**Excludes ''clear cell'', ''chordoid'', ''papillary'', and ''rhabdoid'' subtypes.
**Excludes ''clear cell'', ''chordoid'', ''papillary'', and ''rhabdoid'' subtypes.
*Grade 2 (either #1 or #2):  
*Grade 2 (either #1, #2 or #3):  
*#Brain-invasive meningioma.
*#Brain-invasive meningioma.
*#*Protrusion of meningioma into brain.
*#*Protrusion of meningioma into brain.

Revision as of 16:55, 18 July 2011

Meningioma a very common tumour in neuropathology.

General

Prevalence

  • Common.
  • May be caused by prior radiation.

Radiology

  • Extra-axial.

Prognosis

  • Most are benign.
    • May be malignant.

Genetics

Microscopic

Features (memory device WC):

  • Whorled appearance - key feature.
  • Calcification, psammomatous (target-like appearance; (tight) onion skin).

Images:

Notes:

  • May involute into benign sclerotic tissue.[2]
  • Thick-walled blood vessels = feature of schwannoma.

Morphologic subtypes

  • Many subtypes exist.[3]
  • The histologic subtypes generally don't have much prognostic significance.
    • Some subtypes are high grade by definition; also see histologic grading.

Grade I

  • Meningothelial.
    • Most common.
    • Microscopic: syncytial, nuclear clearing (pseudoinclusions).
  • Fibrous (fibroblastic).
    • Not collagen but looks like it. (It is really laminin or fibronectin).
  • Transistional.
    • Rare.
  • Psammomatous.
    • Microscopic: Psammoma bodies.
  • Angiomatous (vascular).
    • May bleed like stink.
  • Microcystic.
    • Microscopic: cystic appearance.
  • Secretory.
    • Microscopic: intracytoplasmic inclusions that are CEA +ve and PAS +ve.
    • Assoc. with brain edema; may have a worse outcome.
  • Lymphoplasmacyte-rich.
  • Metaplastic.
    • Much talked about... but very rare.
    • Microscopic: cartilage or bone formation.

Grade II

  • Invasive (invades the brain).
  • Clear cell.
    • Microscopic: clear cells - contain glycogen (PAS +ve).
    • Epi.: usu. spinal cord.[4]
  • Chordoid (chordoma-like).
    • Microscopic: myxoid appearance.

Grade III

  • Papillary.
    • Microscopic: true papillae.
  • Rhaboid.
    • Microscopic: rhadoid appearance (abundant cytoplasm).

Histologic grading

Grading:[3]

  • Grade 1:
    • Low mitotic rate (< 4 mitoses/10 HPF - for whatever HPF means, see HPFitis).
    • Excludes clear cell, chordoid, papillary, and rhabdoid subtypes.
  • Grade 2 (either #1, #2 or #3):
    1. Brain-invasive meningioma.
      • Protrusion of meningioma into brain.
        • Meninogioma with entraped GFAP +ve tissue.
    2. Atypical meningioma (by histomorphology) - either A or B.
      • A. Intermediate mitotic rate (>= 4 mitoses/10 HPF - for whatever HPF means, see HPFitis.)
      • B. 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.
    3. Clear cell or chordoid subtype.
  • Grade 3 (either of the following):
    • High mitotic rate (>=20 mitoses/10 HPF - for whatever HPF means, see HPFitis.)
    • "Frank anaplasia"; marked nuclear atypia.
    • Papillary or rhabdoid subtype.

Notes:

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

IHC

  • EMA +ve.[5]
  • Other CKs usually -ve.

DDx of meningioma & IHC[6]

  • S-100 +ve - schwannoma.
    • +ve in ~80% of fibrous meningiomas.
  • CD34 +ve - solitary fibrous tumour.
    • +ve in ~60% of fibrous meningiomas.
  • EMA +ve in ~30% of hemangiopericytoma.
  • Claudin-1 - new kid on the block: +ve in meningioma, but low sensitivity.

Standard work-up (UHN)[7]

  • Ki-67 >5-10% - predicts re-occurrence.
  • PR (progesterone receptor) +ve in 2/3; -ve PR predicts re-occurrence.

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. 3.0 3.1 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. 200. ISBN 978-0443069826.
  5. 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.
  6. Hahn HP, Bundock EA, Hornick JL (February 2006). "Immunohistochemical staining for claudin-1 can help distinguish meningiomas from histologic mimics". Am. J. Clin. Pathol. 125 (2): 203–8. doi:10.1309/G659-FVVB-MG7U-4RPQ. PMID 16393681. http://ajcp.ascpjournals.org/content/125/2/203.full.pdf.
  7. Croul, SE. 8 November 2010.

External links