Meningioma
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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
- May be seen in genetic disorders such as:
- Neurofibromatosis 2 (NF2).[1]
- Nevoid basal cell carcinoma syndrome (Gorlin syndrome).
- Cowden syndrome.
Microscopic
Features (memory device WTC):
- Whorled appearance - key feature.
- Thick-walled blood vessels, usually prominent.
- Calcification.
Images:
Notes:
- May involute into benign sclerotic tissue.[2]
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 work 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.
- Excludes clear cell, chordoid, papillary, and rhabdoid subtypes.
- Grade 2 (either #1 or #2):
- Brain-invasive meningioma.
- Protrusion of meningioma into brain.
- Meninogioma with entraped GFAP +ve tissue.
- Protrusion of meningioma into brain.
- Atypical meningioma (by histomorphology).
- Intermediate mitotic rate (>= 4 mitoses/10 HPF - for whatever HPF means, see HPFitis.)
- Three of the following five features:
- Sheeting architecture.
- High NC ratio clusters; clusters of "lymphocyte-like" cells.
- Hypercellularity.
- Macronucleoli.
- Necrosis not caused by treatment, e.g. radiation or embolization.
- Brain-invasive meningioma.
- 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.[5]
- Other CKs usu. -ve.
See also
References
- ↑ URL: http://moon.ouhsc.edu/kfung/jty1/neurotest/Q13-Ans.htm. Accessed on: 26 October 2010.
- ↑ URL: http://radiographics.rsna.org/content/23/3/785.long. Accessed on: 3 November 2010.
- ↑ 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.
- ↑ 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.
- ↑ 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.