What is a Meningioma of the Brain?
A meningioma is a typically slow-growing tumor that develops from the protective layers (meninges) that cover your brain and spinal cord, not from the brain tissue itself. 1
Understanding Where It Comes From
- Meningiomas arise from specialized cells called arachnoidal cells that are part of the meninges—the three-layered membrane wrapping around your brain like protective packaging 1
- Because these cells exist anywhere the meninges are present, meningiomas can develop in various locations throughout the skull and spine 1
- Think of it as a growth on the "wrapper" of the brain rather than in the brain itself, which is why it's called an "extraaxial" tumor (outside the brain tissue) 2
How Common and Who Gets Them
- Meningiomas are the most common primary brain tumor in adults, making up about 40% of all brain tumors 1
- They occur more frequently in women than men (about 3:2 ratio in adults), though this pattern reverses in children 1, 3
- Most people are diagnosed in middle to late adult life 4
- They can occasionally be linked to genetic conditions like Neurofibromatosis type 2 (NF-2), where 20-40% of childhood cases occur 1
- Previous radiation exposure to the head increases risk 1, 3
How Fast They Grow and Their Behavior
- About 75-80% of meningiomas are benign (WHO grade 1), meaning they grow very slowly and rarely spread 1
- 15-20% are classified as grade 2 (atypical), which grow faster and are more likely to come back after treatment 1
- Only 1-5% are grade 3 (malignant/anaplastic), which are aggressive and have poorer outcomes 1
- The 5-year survival for benign meningiomas exceeds 80%, but drops significantly for higher-grade tumors 3
What Symptoms They Cause
Symptoms depend entirely on where the tumor is located and how large it has grown:
- Headaches are the most common symptom—typically diffuse and progressively worsening over days to weeks 5, 6
- Seizures occur in up to 30% of patients as the tumor irritates the brain's surface 6
- Vision problems including blurred vision or double vision from pressure effects 5, 6
- Weakness or numbness in arms or legs if the tumor presses on motor areas 6
- Drowsiness and vomiting when pressure inside the skull builds up 6
- Some meningiomas are discovered incidentally on brain scans done for other reasons and cause no symptoms at all 1
How They're Diagnosed and Treated
- MRI with contrast is the gold standard test to see the tumor clearly 5, 7
- Surgery to completely remove the tumor is the primary treatment when the location allows safe access 1, 2
- Complete removal is often curative for benign meningiomas 4
- Radiation therapy is used for tumors that can't be completely removed, are in difficult locations, or come back after surgery 3, 2, 4
- For slow-growing tumors causing no symptoms, careful monitoring with regular scans may be appropriate 1
Important Points to Remember
- Most meningiomas are benign and slow-growing, not cancerous brain tumors 1
- They compress rather than invade the brain, which is why complete surgical removal can be curative 2, 4
- Symptoms develop gradually as the tumor slowly enlarges over months to years 6
- Even benign meningiomas require monitoring because they can recur, especially if not completely removed 4