As the most common brain tumor type, meningiomas account for 37.6% of primary brain tumor diagnoses. The typical meningioma grows slowly, often existing for years before it presses on brain structures and causes problems. Smaller meningiomas that aren’t causing symptoms are sometimes discovered by chance during coincidental MRI testing.
Each year in the United States, about 170,000 people learn they have a meningioma tumor. If you’re one of them, gaining a better understanding of your diagnosis is the first step in getting answers to your most pressing questions and easing your concerns.
Here, fellowship-trained neurosurgical oncologist Jose Valerio, MD, explores what a meningioma diagnosis can mean, discusses possible treatment options, and explains the importance of follow-up care.
Meningioma tumor basics
Meningiomas are abnormal growths that emerge within the protective three-layer membrane (meninges) that covers your brain and spinal cord. Specifically, these common primary brain tumors arise from the arachnoid cap cells that make up the middle layer of this vital web-like membrane.
Given that meningiomas grow in the space between your brain and skull, they can only expand in one direction — inward, toward your brain. Although most meningiomas are benign (noncancerous) and don’t invade other tissues, they can grow large enough to press on your brain structures and cause problems.
Tumor location and subtype
Meningioma tumors are categorized by subtype based on where they appear. Because meningiomas can appear in any area of the brain where arachnoid cap cells are, there are many subtypes. Some of the most common are:
One in five meningiomas (20%) are of the convexity subtype, meaning they grow on the surface of the brain, below the skull. Convexity meningiomas may not cause symptoms until they grow large enough to push on underlying brain structures.
Sphenoid wing meningioma
Another one in five meningioma tumors (20%) are sphenoid wing meningiomas, which occur along a ridge of bone behind the eye. These growths may press on your ocular structures and cause vision problems.
Olfactory groove meningioma
About one in 10 meningiomas (10%) occur on the olfactory nerves that connect your nose to your brain. Early on, these tumors can interfere with your sense of smell. As they grow larger, they can cause unexplained vision changes.
Another one in 10 meningiomas (10%) grow on the underside of the brain, where they can readily press on cranial nerves. In some cases, a petrous meningioma can put pressure on the trigeminal nerve, causing a painful facial condition called trigeminal neuralgia.
Tumor characteristics and grade
When you’re diagnosed with a meningioma tumor, Dr. Valerio tells you all about its location and subtype, including the specific ways it can affect your brain function and senses.
He also lets you know the grade of your tumor based on its disease characteristics, which he determines through molecular testing. Meningiomas are graded in three ways:
Grade I (typical)
About four in five meningiomas (80%) are benign, low-grade tumors that grow very slowly.
Grade II (atypical)
Just under one in five meningiomas (17%) are benign, mid-grade tumors that grow more quickly and can be more treatment-resistant, meaning they’ll be more likely to come back after they’ve been removed.
Grade III (anaplastic)
High-grade meningiomas are malignant (cancerous), fast-growing tumors. Less than 2% of diagnosed meningiomas are anaplastic.
Your treatment approach
The specifics of your meningioma treatment plan will depend on the grade, size, and location of your tumor, among other factors, such as the nature and severity of any symptoms you may be having.
If you have a small, typical meningioma that isn’t causing symptoms, Dr. Valerio may advise you to start with regular monitoring to check its progression. If your low-grade meningioma is growing, or if you have a mid-grade tumor that’s growing quickly, he may recommend prompt surgical removal before it starts to put pressure on your brain.
High-grade meningioma malignancies are removed promptly, whenever possible.
A meningioma’s size and location determine how it’s removed, and whether it can be removed completely. In some cases, radiation may be used to help reduce the size of a meningioma or to treat small remnants of a tumor after surgery.
Continuing follow-up care
After meningioma removal, you’ll have regular follow-up MRI scans to ensure the tumor isn’t coming back. In most cases, meningiomas don’t recur within 10 years.
However, in one study, nearly half of surgically treated meningiomas returned after 20 years. Most recurring meningiomas (about 95%) grow back in the same place as the original tumor. For this reason, long-term follow-up monitoring is a key component of every meningioma treatment plan.
From the day you’re diagnosed through every follow-up MRI scan in the years to come, you’re in good hands with Dr. Valerio. To learn more, contact the practice of Jose Valerio, MD, to book an appointment today. We have locations in South Miami, Hialeah, and Weston, Florida.