Meningioma
Usually benign, slow-growing tumors arising from the membranes covering the brain and spinal cord, with symptoms and treatment shaped strongly by the tumor’s grade and exact location.
Quick Answer
A meningioma is a tumor that arises from the meninges, the membranes covering the brain and spinal cord. It is the most common primary brain tumor, and the large majority are benign and slow-growing. Meningiomas are graded 1, 2, or 3, and that grade — more than size — determines how they are treated and how closely they are followed. Where the tumor sits matters as much as its grade: a meningioma over the surface of the brain and one at the base of the skull are the same disease but present differently and are approached differently. Many are found incidentally and can simply be monitored, sometimes indefinitely. Others are removed surgically, often with excellent and lasting results, or treated with stereotactic radiosurgery.
Key Takeaways
- Meningiomas arise from the coverings of the brain and spinal cord and are the most common primary brain tumor.
- Most are benign and slow-growing.
- Meningiomas are graded 1, 2, or 3. Most are grade 1, and the grade guides whether treatment beyond surgery is needed.
- Many small meningiomas causing no symptoms are safely monitored, and a substantial number never require treatment at all.
- Surgery can be curative, particularly when the tumor and its attachment to the covering of the brain are removed completely.
- Stereotactic radiosurgery is an effective option for selected tumors.
- Location shapes both the symptoms and the surgical approach — meningiomas at the base of the skull are among the most technically demanding and are managed by surgeons who work in that region regularly.
At a Glance
| What it is | Tumor arising from the meninges, the coverings of the brain and spinal cord |
|---|---|
| How common | The most common primary brain tumor; more frequent in women and increasingly found incidentally |
| Nature | Most are benign and slow-growing |
| Grades | WHO grade 1, 2, or 3 — the great majority are grade 1 |
| Where they occur | Over the surface of the brain, along the falx, throughout the skull base, and in the spine |
| Common approach | Observation, surgery, or radiosurgery |
| Diagnosis | MRI with contrast, sometimes CT to assess the adjacent bone |
| Molecular findings | TERT promoter mutation or CDKN2A/B deletion indicates grade 3; NF2 and other alterations vary by location |
| Outlook | Often excellent, especially with complete removal |
Types and Grades of Meningioma
Meningiomas are graded 1, 2, or 3 based on how the tumor looks under a microscope and, more recently, on specific genetic findings within it. Grade is not the same as size or symptoms: a large grade 1 meningioma may be entirely curable, while a small grade 3 tumor requires aggressive treatment. It is the single most useful thing to know about a meningioma once it has been removed, because it determines whether treatment beyond surgery is recommended and how closely the tumor is followed afterward.
Grade 1
Most common
The great majority of meningiomas are Grade 1. These grow slowly, often over many years, and frequently cause no symptoms at all. When a grade 1 meningioma is completely removed along with its attachment to the covering of the brain, the operation is usually curative and no further treatment is needed. Many grade 1 meningiomas that are small and causing no symptoms are never treated.
Grade 2
Atypical
Sometimes called atypical meningiomas. They grow faster than grade 1 tumors and return more often after surgery. A meningioma is assigned grade 2 when the cells are dividing more actively than expected, when several specific features of aggressive behavior are present under the microscope, or when the tumor is found to have grown into the surface of the brain rather than simply pressing against it. Complete removal remains the goal, and radiation after surgery is often recommended depending on how completely the tumor was removed and other individual factors.
Grade 3
Uncommon
Uncommon, accounting for a small fraction of meningiomas. These grow quickly, invade surrounding tissue, and recur frequently. Treatment is surgery followed by radiation. Grade 3 can be assigned on microscopic findings, or on either of two genetic findings — a change in the TERT gene promoter or loss of a gene called CDKN2A/B — which establish grade 3 on their own even when the tissue appears less aggressive. This is a recent change in how these tumors are classified, and it identifies a group of patients who need closer treatment than their tumor’s appearance alone would suggest.
What About Meningioma Subtypes?
Pathologists also describe a meningioma’s subtype — fifteen are recognized — based on its appearance under the microscope. Most subtypes do not change management on their own; only the WHO grade does.
Grade and location answer different questions. Grade describes how the tumor is likely to behave. Location tells us what structures are at risk and which treatment approaches are safest. Both matter when building a treatment plan.
Meningioma Types by Location
Meningiomas can arise anywhere the coverings of the brain and spinal cord extend. Location is one of the most important differences between meningiomas because it shapes the symptoms a tumor can cause, the structures that must be protected, and the safest treatment approach.
Choose a location below to explore a dedicated page with the anatomy, symptoms, diagnosis and treatment considerations that are specific to that meningioma subtype.
SURFACE & MIDLINE
Tumors arising over the brain’s surface or along its central dural folds.
SKULL BASE
Deep locations where cranial nerves, major arteries, vision and the brainstem can shape treatment.
SPINE
Tumors arising from the covering of the spinal cord rather than around the brain.
Location can also reflect tumor biology
Location can correlate with a meningioma’s underlying genetics. Meningiomas over the surface of the brain and in the spine commonly carry changes involving NF2, while skull-base tumors more often have other molecular alterations. These patterns are an active area of research and another reason location-specific expertise matters.
Symptoms
Many meningiomas cause no symptoms and are discovered incidentally on imaging done for another reason. When symptoms occur, they result from the tumor pressing on nearby brain, nerves, or the skull, and they depend heavily on location. Possible symptoms include headaches, seizures, weakness or numbness, vision or hearing changes, and changes in thinking or personality.
Because meningiomas usually grow slowly, symptoms tend to develop gradually, and the brain often compensates as the tumor enlarges. Changes that come on over years are frequently attributed to aging or stress before imaging is obtained. That slow onset has an encouraging corollary: deficits that developed gradually often improve substantially once the pressure is relieved, even when they have been present for a long time.
Common Warning Signs
- Gradual headaches
- New seizures
- Vision or hearing changes
- Weakness or numbness
- Changes in thinking or personality
When to Seek Care Promptly
- A first-time seizure
- Sudden severe headache
- Rapidly progressing weakness or vision loss
- New confusion or change in alertness
- Any rapidly worsening neurological symptom
Diagnosis
Meningiomas are usually well seen on MRI with contrast, which shows their characteristic appearance and relationship to surrounding structures. CT can show associated changes in the adjacent bone and any calcification. The appearance is distinctive enough that a meningioma can usually be identified confidently on imaging alone — a broad attachment to the covering of the brain, uniform enhancement with contrast, and often a thickened tail of tissue extending along that covering from the edge of the tumor.
When treatment is planned, additional imaging defines the tumor’s blood supply and its relationship to critical nerves and arteries. Meningiomas draw a rich blood supply from the vessels of the covering of the brain, and for some tumors those feeding vessels are blocked off in a separate procedure (embolization) shortly before surgery to reduce bleeding during the operation. When the tumor is removed, examination of the tissue confirms the diagnosis, establishes the grade, and — where the findings warrant — includes genetic testing that can raise the grade and change what follows. Grade is what guides how closely the tumor is followed and whether radiation is recommended after surgery.
Treatment
Treatment depends on the tumor’s size, location, growth rate, symptoms and grade, as well as the patient’s age and overall health. The goal is not simply to treat the scan—it is to choose the approach that offers durable tumor control while protecting neurologic function.
01
Observation
Many meningiomas are never treated. A small tumor causing no symptoms can be followed with periodic MRI, and a substantial proportion show little or no growth over years. In those cases, monitoring is not a delay before treatment—it is the treatment itself. Size at discovery, calcification, age and interval growth help determine how often imaging is repeated.
02
Surgery
Surgery is considered when a meningioma is growing, causing symptoms or pressing on important structures. Because meningiomas arise from the covering of the brain rather than the brain itself, complete removal is often achievable. When safe, treatment also addresses the dural attachment and any involved bone because those areas influence recurrence risk.
03
Stereotactic Radiosurgery
Stereotactic radiosurgery (SRS) can be used for selected small tumors, tumors in locations where surgery carries greater risk, or residual or recurrent tumor after surgery. The goal is usually long-term growth control rather than disappearance on imaging.
How much tumor should be removed depends heavily on location. Over the surface of the brain, complete removal including the attachment may be straightforward. At the skull base or along major veins, deliberately leaving a small portion and controlling it with focused radiation can offer a better balance of tumor control and neurologic function than pursuing complete removal at all costs.
What successful radiosurgery looks like: The tumor typically remains visible on follow-up imaging. Stability—not disappearance—is the goal. When a tumor lies very close to the optic nerves, radiation may be divided into several sessions to protect vision.
Radiation After Surgery
Whether radiation is recommended after surgery depends heavily on grade. After complete removal of a grade 1 meningioma, no further treatment is usually needed and the tumor is followed with imaging. For grade 2 tumors, postoperative radiation is considered case by case, weighing the extent of removal against the risks of treatment. For grade 3 tumors, radiation after surgery is standard.
There is currently no established drug therapy for meningioma, which is why clinical trials matter most for the small number of patients whose tumors continue to recur despite surgery and radiation.
At Atlantic Brain and Spine, each case is reviewed by a multidisciplinary brain tumor team to determine whether observation, surgery, radiosurgery or a combination offers the best balance of tumor control and preservation of neurologic function.
The Diagnosis-to-Treatment Pathway
1. Detection
A meningioma is found incidentally or after symptoms develop.
2. Imaging
Contrast MRI defines the tumor, its location, and its relationship to nearby structures; CT may assess bone or calcification.
3. Observation or treatment decision
Size, growth, symptoms, location, age, and overall health guide whether monitoring or treatment is appropriate.
4. Surgery when indicated
The goal is to remove the tumor and its attachment as completely as can be done safely.
5. Pathology and grade
Tissue examination confirms the diagnosis and establishes WHO grade; selected tumors also undergo genetic testing.
6. Radiation or radiosurgery if needed
Focused radiation may treat selected tumors, residual or recurrent disease, or higher-grade tumors after surgery.
7. Follow-up
MRI surveillance is tailored to tumor grade, extent of removal, and treatment history.
Frequently Asked Questions
The large majority of meningiomas are benign and slow-growing. Meningiomas are graded 1, 2, or 3; grade 1 tumors are the most common, while grade 2 tumors recur more often and grade 3 tumors are uncommon and more aggressive. Even a benign meningioma can cause problems if it presses on important brain, nerve, or vascular structures.
No. Many small meningiomas that are not causing symptoms can be followed with periodic MRI, sometimes indefinitely. Treatment is considered when a tumor is growing, causing symptoms, or threatening important structures.
Yes, particularly for accessible grade 1 tumors. When the tumor, its attachment to the covering of the brain, and any involved bone can be removed completely and safely, surgery is often curative. Location can limit how much should be removed.
Stereotactic radiosurgery may be used for selected small tumors, tumors in locations where surgery carries greater risk, or residual or recurrent tumor after surgery. It is designed to control growth rather than make the tumor disappear on follow-up imaging.
Symptoms depend heavily on location and may include headaches, seizures, weakness or numbness, vision or hearing changes, and changes in thinking or personality. Many meningiomas cause no symptoms and are found incidentally.
Recurrence risk depends on the tumor grade, location, and how completely the tumor and its attachment were removed. Grade 1 tumors that are completely removed often do not require further treatment, while grade 2 and grade 3 tumors need closer follow-up and may require radiation.
Grade describes how the tumor behaves and is one of the most important factors guiding follow-up and treatment after surgery. Most meningiomas are grade 1. Grade 2 tumors grow faster and return more often, while grade 3 tumors are uncommon, grow more aggressively, and are generally treated with surgery followed by radiation.
Specialists Who Treat Meningiomas
Meningioma care at Atlantic Brain and Spine is provided by neurosurgeons with specialized expertise in complex brain and skull base tumors, working as part of a multidisciplinary brain tumor team.
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