A meningioma is a type of tumor that forms in the meninges, which are the protective layers of tissue covering the brain and spinal cord. About 90 percent of meningiomas are benign (non-cancerous), although some can be cancer-causing.
Most meningiomas grow very slowly, so they may not cause any noticeable symptoms for many years. However, depending on where they are located, they can place pressure on important structures in the brain and interfere with functions such as vision, hearing, speech, memory or motion. While they can affect anyone of any age, they are most commonly diagnosed in adults age 40-60 and are twice as common in women as in men.
Not all meningiomas cause symptoms, especially when they are small. The most common symptoms include:
- Blurry vision or double-vision
- Numbness or weakness in the arms or legs
- Hearing loss or ringing in the ears
- Difficulty speaking
- Memory loss
Meningiomas are most commonly diagnosed using tests such as:
- Observation (Also called “watchful waiting”) – If a meningioma is small and is not currently causing symptoms, your doctor may choose to observe it over time. This typically involves ordering periodic imaging tests such as CT or MRI scans to monitor its growth.
- Surgery – Depending on the location of the tumor, it is often possible to remove all or most of the meningioma through open craniotomy. This procedure involves making an incision in the scalp and removing a piece of bone from the skull. The neurosurgeon can then access and remove the tumor, or as much of the tumor as possible without damaging other brain tissue.
- Gamma Knife Radiosurgery – Gamma Knife® uses highly targeted radiation to treat brain abnormalities such as meningiomas with submillimeter precision. It can shrink a meningioma up to 90 percent, reducing its impact and controlling symptoms without the need to surgically remove it. Gamma Knife surgery is safer than open craniotomy with faster recovery times and is more precise than any other radiosurgery device including CyberKnife®. Therefore, it is often recommended when the location of the meningioma makes it difficult to remove surgically without damaging nearby brain structures or when the patient may not be able to withstand open brain surgery
A 2016 study of long-term outcomes found that Gamma Knife stereotactic radiosurgery provided durable tumor control with low morbidity in meningioma patients. The overall tumor control rate was 91 percent. More than 87 percent of patients had no tumor progression at 10 and 20 years after treatment. Among the patients who had symptoms before treatment, 26 percent saw improvement, 54 percent had no change in symptoms and 46 percent gradually worsened.
Source: Am J Clin Oncol. 2016 Oct; 39(5):453-7. doi: 10.1097/COC.0000000000000080.
In rare cases, a meningioma can grow back after treatment with surgery or radiosurgery. Therefore, doctors typically recommend that patients have follow-up CT or MRI scans every few years to monitor for possible growth of the tumor.