Meningioma

Overview

Meningiomas are tumors that develop from the meninges, the protective layers of tissue that cover the brain and spinal cord. They represent approximately 30% of all primary brain tumors, making them the most common type of brain tumor in adults. While the vast majority (about 90%) of meningiomas are benign (non-cancerous), they can still cause significant health problems due to their location and the pressure they exert on surrounding brain tissue.

These tumors typically grow slowly over many years and may remain asymptomatic for extended periods. Many meningiomas are discovered incidentally during brain imaging performed for unrelated reasons. The tumors can occur anywhere along the meninges but are most commonly found over the convexities of the brain, along the falx cerebri (the membrane separating the two hemispheres), and at the skull base. The location of the tumor largely determines the symptoms a patient may experience.

Meningiomas affect women more frequently than men, with a ratio of approximately 2:1, and are most commonly diagnosed in people between the ages of 40 and 70. While most meningiomas are sporadic, meaning they occur without a clear cause, certain genetic conditions and environmental factors can increase the risk of developing these tumors. The treatment approach varies depending on the tumor's size, location, growth rate, and the symptoms it causes, ranging from careful observation to surgical removal or radiation therapy.

Symptoms

The symptoms of meningioma vary significantly depending on the tumor's size, location, and rate of growth. Many small meningiomas cause no symptoms and are found incidentally. When symptoms do occur, they typically develop gradually over months or years.

Common Symptoms

• Headache: The most common symptom, occurring in about 50% of patients. Headaches are often worse in the morning and may progressively worsen over time. They result from increased intracranial pressure or local irritation of pain-sensitive structures.
• Dizziness: Can occur due to pressure on brain regions controlling balance or from increased intracranial pressure. Patients may experience vertigo, unsteadiness, or a general feeling of being off-balance.
• Weakness: Focal weakness in arms or legs can develop when the tumor compresses motor areas of the brain or spinal cord. The pattern of weakness depends on the tumor location.
• Disturbance of memory: Memory problems, confusion, and cognitive changes can occur, particularly with frontal or temporal lobe meningiomas. Patients may experience difficulty with short-term memory, concentration, or executive function.
• Depressive or psychotic symptoms: Personality changes, mood disturbances, depression, or even psychotic symptoms can occur, especially with frontal lobe meningiomas. These may be the only symptoms in some cases.

Location-Specific Symptoms

• Convexity meningiomas: Seizures, focal neurological deficits, headaches
• Parasagittal/falx meningiomas: Leg weakness, personality changes, seizures
• Sphenoid wing meningiomas: Vision problems, facial numbness, seizures
• Olfactory groove meningiomas: Loss of smell, personality changes, visual disturbances
• Posterior fossa meningiomas: Balance problems, hearing loss, facial weakness
• Spinal meningiomas: Back pain, weakness, sensory changes in limbs

Additional Symptoms

• Seizures: Occur in 25-30% of patients, may be focal or generalized
• Vision changes: Blurred vision, double vision, or visual field defects
• Hearing problems: Hearing loss or tinnitus with skull base tumors
• Speech difficulties: Problems with language expression or comprehension
• Sensory changes: Numbness, tingling, or altered sensation
• Hormonal imbalances: With tumors near the pituitary gland

Red Flag Symptoms

• Sudden severe headache with neurological deficits
• Rapid progression of symptoms
• New-onset seizures in adults
• Progressive weakness or sensory loss
• Changes in consciousness or alertness

Causes

The exact cause of most meningiomas remains unknown, but researchers have identified several factors that contribute to their development. Understanding these causes helps in risk assessment and potentially in prevention strategies.

Genetic Factors

• Chromosome 22 abnormalities: Loss of chromosome 22 or mutations in the NF2 gene are found in 40-70% of meningiomas
• Neurofibromatosis type 2 (NF2): Patients with this genetic disorder have a significantly increased risk of developing multiple meningiomas
• Other genetic syndromes: Including Gorlin syndrome, Werner syndrome, and multiple endocrine neoplasia type 1
• Familial clustering: Rare families with multiple affected members suggest genetic predisposition

Environmental Factors

• Radiation exposure:
  • Previous radiation therapy to the head (strongest known risk factor)
  • Atomic bomb radiation exposure
  • Dental X-rays (historical high-dose exposures)
  • Occupational radiation exposure
• Head trauma: Some studies suggest a possible link, though evidence is inconclusive
• Cell phone use: No conclusive evidence of increased risk despite ongoing research

Hormonal Influences

• Sex hormones: Higher incidence in women suggests hormonal influence
• Progesterone receptors: Found in 60-90% of meningiomas
• Pregnancy: May accelerate growth of existing meningiomas
• Hormone replacement therapy: Possible increased risk with long-term use
• Breast cancer: Slightly increased risk in breast cancer survivors

Other Potential Factors

• Age: Risk increases with age, peak incidence in 6th-7th decade
• Obesity: Some studies suggest increased risk
• Previous viral infections: Under investigation but not proven
• Occupational exposures: Certain chemicals and solvents being studied

Risk Factors

Several factors increase the likelihood of developing a meningioma. Understanding these risk factors helps identify individuals who may benefit from increased surveillance or preventive measures.

Demographic Risk Factors

• Gender: Women are twice as likely to develop meningiomas as men
• Age: Risk increases with age, most common in people aged 40-70
• Race: Slightly higher incidence in African Americans compared to Caucasians

Medical History Risk Factors

• Previous radiation therapy:
  • Cranial radiation for other conditions
  • Risk increases with dose and decreases with age at exposure
  • Latency period of 10-30+ years
• Genetic conditions:
  • Neurofibromatosis type 2 (highest risk)
  • Schwannomatosis
  • Multiple endocrine neoplasia type 1
  • Cowden syndrome
• Hormonal factors:
  • Pregnancy (may accelerate growth)
  • Use of hormone replacement therapy
  • Oral contraceptive use (controversial)
  • Fertility treatments

Lifestyle and Environmental Factors

• Obesity: BMI >30 associated with increased risk in some studies
• Head injury: Possible but unproven association
• Occupational exposures: Under investigation for certain chemicals
• Dental X-rays: Historical high-dose exposures (modern dental X-rays use much lower doses)

Protective Factors

• Allergy history: Some studies suggest reduced risk in people with allergies
• NSAIDs use: Regular use may be associated with lower risk
• Physical activity: May have protective effects

Diagnosis

Diagnosing meningioma involves a combination of clinical evaluation, neuroimaging studies, and sometimes tissue diagnosis. Early and accurate diagnosis is crucial for appropriate management planning.

Clinical Evaluation

• Medical history:
  • Detailed symptom timeline and progression
  • Previous radiation exposure
  • Family history of brain tumors
  • Hormonal history in women
• Neurological examination:
  • Mental status and cognitive assessment
  • Cranial nerve examination
  • Motor and sensory testing
  • Coordination and gait assessment
  • Fundoscopic examination for papilledema

Imaging Studies

• MRI (Magnetic Resonance Imaging):
  • Gold standard for diagnosis and surgical planning
  • T1-weighted images with gadolinium show homogeneous enhancement
  • "Dural tail" sign - characteristic but not pathognomonic
  • T2-weighted images assess edema and mass effect
  • Advanced sequences (perfusion, spectroscopy) for atypical cases
• CT (Computed Tomography):
  • May show hyperostosis (bone thickening) adjacent to tumor
  • Calcifications present in 20-25% of cases
  • Useful for surgical planning and bone involvement
  • CT angiography for vascular assessment
• Angiography:
  • Assesses tumor vascularity
  • Identifies feeding arteries
  • May allow preoperative embolization

Grading and Classification

• WHO Grade I (Benign): 80-90% of meningiomas, slow-growing
• WHO Grade II (Atypical): 5-15%, increased recurrence risk
• WHO Grade III (Malignant/Anaplastic): 1-3%, aggressive behavior

Differential Diagnosis

Conditions that may mimic meningioma:

• Metastatic brain tumors
• Schwannomas
• Hemangiopericytomas
• Dural metastases
• Lymphomas
• Inflammatory conditions (sarcoidosis, tuberculosis)

Additional Testing

• Visual field testing: For tumors near visual pathways
• Audiometry: For posterior fossa tumors
• Hormonal assessment: For sellar/parasellar tumors
• Neuropsychological testing: Baseline cognitive function

Treatment Options

Treatment for meningioma depends on multiple factors including tumor size, location, growth rate, symptoms, patient age, and overall health. The approach ranges from observation to aggressive multimodal therapy.

Observation (Active Surveillance)

Appropriate for:

• Small, asymptomatic tumors discovered incidentally
• Elderly patients with limited life expectancy
• Patients with significant surgical risks
• Slow-growing tumors in non-critical locations

Protocol includes:

• Initial MRI at 3-6 months, then annually if stable
• More frequent imaging if growth detected
• Neurological examinations every 6-12 months
• Intervention if symptoms develop or significant growth occurs

Surgical Treatment

Goals and considerations:

• Complete resection:
  • Simpson Grade I - Complete removal including dural attachment and bone
  • Simpson Grade II - Complete removal with coagulation of dural attachment
  • Best chance for cure, especially for Grade I tumors
• Subtotal resection:
  • When complete removal risks neurological deficits
  • Tumors involving critical structures (cavernous sinus, brainstem)
  • May require adjuvant radiation therapy
• Surgical approaches:
  • Craniotomy - traditional open surgery
  • Minimally invasive techniques when appropriate
  • Endoscopic approaches for skull base tumors
  • Image-guided navigation for precision

Radiation Therapy

• Stereotactic radiosurgery (SRS):
  • Single high-dose radiation treatment
  • For tumors <3 cm diameter
  • Control rates >90% at 5 years
  • Gamma Knife, CyberKnife, or linear accelerator-based
• Fractionated radiation therapy:
  • Multiple lower-dose treatments over weeks
  • For larger tumors or those near critical structures
  • Intensity-modulated radiation therapy (IMRT)
  • Proton beam therapy for selected cases
• Indications for radiation:
  • Residual tumor after surgery
  • Recurrent tumors
  • WHO Grade II or III tumors
  • Inoperable tumors
  • Patients who are poor surgical candidates

Medical Therapy

• Antiepileptic drugs: For patients with seizures
• Corticosteroids: To reduce peritumoral edema
• Hormone therapy: Under investigation for hormone receptor-positive tumors
• Chemotherapy: Limited role, mainly for malignant meningiomas
• Targeted therapy: Clinical trials with bevacizumab, sunitinib

Treatment Complications

• Surgical risks: Bleeding, infection, CSF leak, neurological deficits
• Radiation side effects: Fatigue, hair loss, cognitive changes, radiation necrosis
• Long-term monitoring: For recurrence and late effects

Prevention

While most meningiomas cannot be prevented due to their unclear etiology, certain measures may reduce risk or enable early detection in high-risk individuals.

Primary Prevention

• Radiation exposure limitation:
  • Minimize unnecessary medical radiation
  • Use appropriate shielding during X-rays
  • Alternative imaging when possible (ultrasound, MRI)
  • Particular caution in children and young adults
• Hormonal considerations:
  • Discuss risks of long-term hormone replacement therapy
  • Monitor known meningiomas during pregnancy
  • Consider alternatives to hormonal treatments when appropriate
• Lifestyle modifications:
  • Maintain healthy body weight
  • Regular physical activity
  • Healthy diet rich in fruits and vegetables
  • Avoid unnecessary head trauma (wear helmets when appropriate)

Screening and Early Detection

• High-risk individuals:
  • Neurofibromatosis type 2 patients - annual MRI screening
  • Previous cranial radiation - periodic imaging after latency period
  • Strong family history - consider genetic counseling
• Symptom awareness:
  • Education about warning signs
  • Prompt evaluation of persistent headaches
  • Attention to cognitive or personality changes
  • Regular neurological check-ups for at-risk individuals

Secondary Prevention

• Post-treatment surveillance:
  • Regular MRI monitoring after treatment
  • Early detection of recurrence
  • Management of treatment-related complications
• Risk factor modification:
  • Hormone therapy reassessment in patients with meningiomas
  • Seizure prevention in at-risk patients
  • Management of modifiable risk factors

When to See a Doctor

Early medical evaluation is important for symptoms that could indicate a brain tumor. While many symptoms have benign causes, persistent or progressive symptoms warrant investigation.

Seek Immediate Medical Attention For:

• Sudden severe headache unlike previous headaches
• New-onset seizures or convulsions
• Sudden weakness or paralysis
• Sudden vision loss or double vision
• Difficulty speaking or understanding speech
• Severe dizziness with nausea and vomiting
• Changes in consciousness or confusion

Schedule an Appointment For:

• Persistent headaches that worsen over time
• Progressive memory problems or cognitive changes
• Gradual weakness in arms or legs
• Personality changes or mood disturbances
• Balance problems or frequent falls
• Gradual vision or hearing changes
• Persistent nausea without clear cause

Regular Monitoring If You Have:

• Previous diagnosis of meningioma
• History of cranial radiation
• Neurofibromatosis type 2
• Family history of brain tumors
• Previous cancer with brain metastasis risk

What to Tell Your Doctor:

• Complete symptom timeline and progression
• Any history of radiation exposure
• Family history of brain tumors or genetic conditions
• Current medications, especially hormones
• Impact of symptoms on daily activities

Related Conditions

• Brain Tumor - General category including various types of brain tumors
• Acoustic Neuroma - Another benign tumor that can cause similar symptoms
• Pituitary Adenoma - Benign tumor that may present similarly
• Glioblastoma - Malignant brain tumor requiring different treatment
• Neurofibromatosis - Genetic condition increasing meningioma risk
• Brain Metastases - Important differential diagnosis

Frequently Asked Questions

References

1. Ostrom QT, et al. CBTRUS Statistical Report: Primary Brain and Other Central Nervous System Tumors. Neuro Oncol. 2023.
2. Goldbrunner R, et al. EANO guideline on the diagnosis and management of meningiomas. Neuro Oncol. 2023.
3. Rogers L, et al. Meningiomas: knowledge base, treatment outcomes, and uncertainties. J Neurosurg. 2023.
4. Brastianos PK, et al. Advances in multidisciplinary therapy for meningiomas. Neuro Oncol. 2023.
5. WHO Classification of Tumours Editorial Board. Central nervous system tumours. 5th ed. 2021.