Meningioma
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 WCN):
- Whorled appearance - key feature.
- Calcification, psammomatous (target-like appearance; (tight) onion skin).
- +/-Nuclear pseudoinclusions - focal nuclear clearing with a sharp interface to unremarkable chromatin.
Images:
- Meningioma - high mag. (WC).
- Meningioma - intermed. mag. (WC).
- Meningioma (neuropathologyweb.org).
- Meningioma with brain invasion - intermed. mag. (WC).
- Meningioma with brain invasion - high mag. (WC).
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
- AKA fibroblastic.
- Not collagen but looks like it. (It is really laminin or fibronectin).
Transistional
- Rare.
Psammomatous
Microscopic:
Angiomatous
- AKA vascular.
- May bleed like stink.
Microcystic
Microscopic:
- Cystic appearance.
Secretory
- Assoc. with brain edema; may have a worse outcome.
Microscopic:[4]
- Eosinophilic intracytoplasmic inclusions that are CEA +ve and PAS +ve.
DDx:
- Metastatic mucinous adenocarcinoma.
Lymphoplasmacyte-rich
Microscopic:
- Lymphocytes.
- Plasma cells.
Metaplastic
- Much talked about... but very rare.
Microscopic:
- Cartilage or bone formation.
Grade II
Invasive
- Invades the brain.
Images:
Clear cell
Epidemiology:
- Usu. spinal cord.[5]
Microscopic:
- Clear cells - contain glycogen (PAS +ve).
Images:
Chordoid
- Chordoma-like.
Microscopic:
- Myxoid appearance.
Image:
Grade III
Papillary
Microscopic:
- True papillae.
Rhaboid
Microscopic:
- Rhabdoid 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):
- Brain-invasive meningioma.
- Protrusion of meningioma into brain.
- Meninogioma with entraped GFAP +ve tissue.
- Protrusion of meningioma into brain.
- 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:
- Clear cell or chordoid subtype.
- 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.
- Papillary or rhabdoid subtype.
Notes:
- Grade II soft criteria memory device HMNs: hypercellular, macronucleoli, NC ratio increased, necrosis, sheeting.
IHC
- EMA +ve.[6]
- Other CKs usually -ve.
DDx of meningioma & IHC[7]
- 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)[8]
- Ki-67 >5-10% - predicts re-occurrence.
- PR (progesterone receptor) +ve in 2/3; -ve PR predicts re-occurrence.
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.
- ↑ URL: http://moon.ouhsc.edu/kfung/jty1/Com04/Com405-1-Diss.htm. Accessed on: 12 October 2011.
- ↑ 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.
- ↑ 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.
- ↑ Croul, SE. 8 November 2010.