Meningioma
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Meningiomas are the most common primary brain tumour (37%). They are usually benign (WHO Grade I), slow-growing, and arise from the arachnoid cap cells of the meninges, not the brain tissue itself.
They are extra-axial (outside the brain parenchyma), pushing the brain away rather than invading it.
Clinical Scenario: The Personality Change
A 60-year-old woman is brought in by her husband due to a 2-year history of personality changes (apathy) and loss of smell (anosmia). On examination, she has optic atrophy in the right eye and papilloedema in the left.
Key Teaching Points
- This is **Foster Kennedy Syndrome**.
- Caused by a large **Olfactory Groove Meningioma**.
- **Mechanism**: Direct compression of the ipsilateral optic nerve (Atrophy) and olfactory nerve (Anosmia), plus raised ICP causing contralateral Papilloedema.
- Personality change is due to Frontal Lobe compression.
Image Integration Plan
| Image Type | Source | Status |
|---|---|---|
| Management Algorithm | AI-generated | PENDING |
| MRI T1 Contrast (Dural Tail) | Web Source | PENDING |
| Histology (Psammoma Bodies) | Web Source | PENDING |
| Locations Map (Parasagittal/Falx) | Web Source | PENDING |
[!NOTE] Image Generation Status: Diagrams illustrating the Extra-axial compression vs Intra-axial invasion are queued.
WHO Grading
- Grade I (Benign): 90%. Slow growth.
- Grade II (Atypical): 5-7%. Higher recurrence.
- Grade III (Anaplastic/Malignant): 1-3%. Aggressive, invasive.
- Incidence: Increases with age (Peak 65+).
- Sex: Females > Males (2:1).
- Note: Meningiomas have Progesterone/Estrogen receptors and can grow during pregnancy.
- Risk Factors:
- Ionising Radiation (previous radiotherapy).
- Neurofibromatosis Type 2 (NF2): Associated with multiple meningiomas.
- Hormone Replacement Therapy (HRT) - weak association.
- Origin: Arachnoid cap cells (outer layer of arachnoid membrane).
- Growth: Expansile growth compresses adjacent brain / cranial nerves.
- Bone: Often induce Hyperostosis (thickening) of the overlying skull.
- Histology: Whorled cells + Psammoma Bodies (calcified concentric lamellae).
Symptoms depend on location. Often asymptomatic ("Incidentaloma").
General
Focal Syndromes (by location)
- Cranial Nerves: Anosmia? Visual fields? Facial numbness?
- Fundoscopy: Papilloedema (Raised ICP). Optic Atrophy (Direct compression).
- Limbs: Upper Motor Neuron signs (Hyperreflexia, Clonus) if motor strip compressed.
Neuro-Imaging
- MRI Brain with Contrast (Gadolinium): Gold Standard.
- Dural Tail Sign: Enhancing tail of dura extends from the mass (60-70% specific).
- Vivid Enhancement: Very bright.
- Cleft Sign: CSF cleft between tumour and brain (confirms extra-axial).
- CT Head:
- Shows Calcification.
- Shows Hyperostosis of bone.
- Angiography: Can be embolised pre-operatively to reduce bleeding (tumours are very vascular).
A. Observation ("Watch and Wait")
- Indications: Small (<2-3cm), Asymptomatic, Elderly patients, Incidental finding.
- Protocol: Serial MRI at 6 months, then annually.
B. Surgical Resection
- Indications: Symptomatic, Large, Growing, Oedema present.
- Goal: Maximal Safe Resection.
- Simpson Grading (Predicts recurrence):
- Grade I: Total removal of tumour + dural attachment + bone (Gold Standard).
- Grade II: Total removal + coagulation of dura.
- Grade IV: Subtotal resection.
C. Radiotherapy / Radiosurgery
- Stereotactic Radiosurgery (Gamma Knife/CyberKnife):
- For small tumours in inaccessible areas (e.g. Cavernous Sinus, Skull Base).
- Or for residual/recurrent tumour.
- Fractionated Radiotherapy: For Grade II/III tumours.
- Seizures: Pre-op or Post-op.
- Mass Effect / Herniation.
- Venous Sinus Invasion: Parasagittal tumours can invade the Superior Sagittal Sinus, making complete removal impossible/dangerous.
- Grade I: Excellent. 5-year survival > 90%. Curable with surgery.
- Recurrence: 20% at 20 years for Grade I. Frequent for Grade II/III.
- EANO Guidelines: Diagnosis and treatment of meningiomas.
- Simpson D. The recurrence of intracranial meningiomas after surgical treatment. (Classic paper establishing Simpson Grades).
What is a Meningioma? It is a brain tumour, but it doesn't grow from the brain cells. It grows from the lining covering the brain (the meninges). Most (9 out of 10) are benign, meaning they are not cancer and do not spread to other parts of the body.
Why is it a problem? Although it is benign, as it grows, it pushes into the brain. Because the skull is a fixed box, there is no room for it. This pressure can cause headaches, fits (seizures), or weakness in an arm or leg.
Do I need an operation?
- Small ones: If we found it by accident and it's tiny, we might just scan it every year to make sure it isn't growing. Many never cause problems.
- Large ones: If it is causing symptoms, we recommend surgery to remove it.
Is surgery dangerous? Brain surgery always carries risk, but for meningiomas on the surface of the brain, the outcomes are usually excellent. If the tumour is stuck to deep blood vessels, we might leave a tiny piece behind and zap it with focused radiotherapy later.
- Goldbrunner R, et al. EANO guidelines for the diagnosis and treatment of meningiomas. Lancet Oncol. 2016.
- Simpson D. The recurrence of intracranial meningiomas after surgical treatment. J Neurol Neurosurg Psychiatry. 1957.
- Whittle, et al. Meningiomas. Lancet. 2004.