A meningioma is a tumor that grows from the dura which is part of the meninges, the membranes that surround the brain and spinal cord. Most meningiomas are noncancerous (benign), though rarely a meningioma may be cancerous (malignant). Some meningiomas are classified as atypical, meaning they’re neither benign nor malignant but, rather, something in between. There is a classification called the WHO (world health organization) classification which assigns a grade to these tumors based on the features seen under a microscope and other special staining features.

There are three main grades (classifications) of meningiomas:

  • Grade I – Benign meningioma: This non-cancerous type of brain tumor grows slowly and has distinct borders. Approximately 75-80% of meningiomas are benign (non-cancerous).
  • Grade II – Atypical meningioma: Approximately 15-20% of meningiomas are atypical, meaning that the tumor cells do not appear typical or normal. Atypical meningiomas are neither malignant (cancerous) nor benign, but may become malignant. Grade II atypical meningiomas also tend to recur and grow faster.
  • Grade III – Malignant or anaplastic meningioma: Malignant or anaplastic meningioma is an aggressive type of brain tumor that tends to invade the parts of the brain nearest to the tumor. Approximately 1-4% of meningiomas are grade III (cancerous).

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Meningiomas occur most commonly in older women. But a meningioma can occur in males and at any age, including childhood. Some meningioma doesn’t always require immediate treatment. A meningioma which is small and causes no significant signs and symptoms may be monitored over time usually with serial scanning using MRI.


  • Intermittent or constant severe headaches
  • Problems with vison
  • Epileptic siezures
  • Episodes of passing out on multiple occasions often accompanied by headaches
  • Hearing loss
  • Memory loss
  • Loss of smell
  • Weakness in arms or legs
  • Speech difficulties


It isn’t clear what causes a meningioma. Doctors know that something alters some cells in your meninges to make them multiply out of control, leading to a meningioma tumor. But whether this occurs because of genes you inherit, things you’re exposed to in your environment, hormones or a combination of these factors remains unknown

Risk Factors

  • Most meningiomas occur sporadically with no known risk factors
  • Radiation treatment. Radiation therapy that involves radiation to the head may increase the risk of a meningioma.
  • Female hormones. Meningiomas are more common in women, leading doctors to believe that female hormones may play a role.
  • An inherited nervous system disorder. The rare disorder neurofibromatosis type 2 increases the risk of meningioma and other brain tumors.


Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include:

  • CT scan of the brain
  • MRI scan of the brain


There are no current guidelines to prevent meningioma.


Talk with your doctor about the best treatment plan for you.

  • The treatment recommended for a meningioma depends on many factors, including the size of the meningioma, where it’s located and how aggressive it’s believed to be. Consideration of age your overall health and your goals for treatment.
  • Immediate treatment isn’t necessary for everyone with a meningioma. A small, slow-growing meningioma that isn’t causing signs or symptoms may not require treatment.
  • If the plan is not to undergo treatment for your meningioma, you’ll likely have brain scans periodically to evaluate your meningioma and look for signs that it’s growing, which is called observation and serial scanning.
  • If your doctor determines your meningioma is growing and needs to be treated, there are several treatment options.


Surgery or Radiosurgery

If your meningioma causes signs and symptoms or causes pressure on the brain, or shows signs that it’s growing, surgery is usually recommended. The goal is to remove the meningioma completely. But because a meningioma may occur near many delicate structures in the brain or spinal cord, it isn’t always possible to remove the entire tumor. In those cases, the goal is to remove as much of the meningioma as possible. In cases where the tumor is small and or entwined with delicate structures, including important vessels or cranial nerves, then radiosurgery commonly performed using gamma knife or cyberknife may be considered The type of treatment, if any, which is needed after surgery depends on several factors.

  • If no visible tumor remains, then no further treatment may be necessary. However, periodic follow-up scans are advised.
  • If the tumor is benign and only a small piece remained, then your doctor may recommend periodic follow-up scans only. In some cases, small leftover tumors may be treated with a form of radiation treatment called stereotactic radiosurgery which is typically done with Gamma Knife or Cyberknife.
  • If the tumor is atypical or malignant, often radiation is recommended.

The recurrence rate after surgery can depend on the extent of the surgical removal

Simpson Grade Completeness of Resection 10-year Recurrence
Grade I Complete removal including resection of underlying bone and associated dura 9%
Grade II Complete removal and coagulation of dural attachment 19%
Grade III Complete removal without resection of dura or coagulation 29%
Grade IV Subtotal resection 40%

Patient Video

Dr David W Newell describes the basic approaches that neurosurgeons consider when encountering a new patient with the diagnosis of brain tumor.

A meningioma is a tumor that grows from the dura which is part of the meninges. For help with symptoms, pain, risks, and treatment contact us or see Seattle Neurosciences’ website.

Dr. Newell was born in Boston, MA and attended Case Western Reserve University medical school. He then completed his residency in neurosurgery at the University of Washington, including one year in London at St. George’s medical school. Dr. Newell is the co-founder of the Swedish Neuroscience Institute and founder of the Seattle Neuroscience Institute.