Meningiomas account for 14% to 19% of all primary intracranial neoplasms, with a peak incidence around 45 years of age and a female preponderance.28,154,155 Predisposing factors include:156

  • previous radiation
  • type II neurofibromatosis
  • monosomy and/or deletions of chromosome 22

Meningiomas arise from the arachnoid cap cells and form an encapsulated mass that is usually slow growing, eventually creating mass effect on the brain (see Figure 5). Histologically, they classically manifest a whorled cellular pattern, psammoma bodies with differing degrees of fibrous connective tissue, blood vessels, and, if malignant, mitotic activity and invasion of cortex.

Generally, meningiomas are classified on a four-grade system:

  • Grade I—benign
  • Grade II—atypical
  • Grade III—anaplastic
  • Grade IV—sarcomatous

The great majority of meningiomas (94%) are benign.158

Location and presentation

Meningiomas most commonly arise on the brain convexity or in a parasagittal location (36%), with 50% located between the coronal and lambdoid sutures and 20% anterior to the coronal suture.157

Headaches are a common symptom, but one study found seizures in 64.7% of patients.28 In Penfield’s series,20, 68% of meningiomas were associated with seizures.

Treatment and outcome

Complete surgical resection should be the goal for accessible tumors. A 4.2-fold excess risk of death has been reported with partial resection compared to gross total resection.163 Adjuvant radiation treatment, although controversial, has been used with some success. In one study the time to recurrence after nonradiated subtotal resections was 66 months, versus 125 months for radiated subtotal resections.164

Stereotactic radiosurgery (SRS) is now used to treat meningiomas that are nonoperable, small, recurrent, or a result of a subtotal resection. The goal is to prevent further tumor growth and preserve normal neurologic function. This is a safe and effective primary or adjuvant therapeutic strategy.165–168 SRS is not indicated for large tumors (>3 cm) or those less than 5 mm from the optic nerve or chiasm.

Few studies focus on seizure outcomes after resections of meningiomas. Flyger and colleagues studied the neogenesis of seizure disorders postresection.161 They observed that 41.1% of patients with no preoperative seizure disorder developed epilepsy postoperatively. Similarly, Foy et al. reported a 22% risk of postoperative seizures after meningioma resection.162Parietal tumors were the most epileptogenic, followed by frontal and occipital tumors.

Predicting recurrence is related to tumor grade and degree of resection. Benign tumors recur in 3% at 5 years, compared to 78% recurrence at 5 years for anaplastic tumors.159 Gross total resection has a reported recurrence rate of 7% at 5 years, compared to 37% if the resection is partial.160

Adapted from: Mangano FT, McBride AE, and Schneider SJ. Brain tumors and epilepsy. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;175–194.
With permission from Elsevier (www.elsevier.com). 

Authored By: 
Steven C. Schachter, MD
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Authored Date: 
02/2004