The 50-year-old singer ("If It Makes You Happy," "Every Day Is a Winding Road") divulged her diagnosis, reportedly made last November, to a reporter Friday during an interview.
These tumors are usually benign, says Marvin Bergsneider, MD, professor of neurological surgery and director of the benign skull-based and pituitary tumor program at UCLA's David Geffen School of Medicine.
Bergsneider is not treating Crow, but does treat many meningioma patients. He answered these questions for WebMD:
What is a meningioma?
First, some anatomy. The meninges are layers of tissue that surround the brain. A meningioma is a tumor that comes from those cells that make up those layers of tissue that surround the brain.
[If benign] it's not a tumor that is within the brain itself. It is actually on the surface of the brain. When the tumor grows, it just pushes on the brain but does not invade the brain.
Are they always benign?
No. We grade them: grade 1, 2, 3. Most, 85%, are benign, grade 1. The other 14% are grade 2.
The malignant meningiomas are fortunately rare -- the other 1%. Malignant ones are often associated with radiation given a long time ago, 15 or 20 years ago.
How do you decide if they are benign or not?
A slow rate of growth is consistent with benign behavior. For tumors removed surgically, the pathologist grades the tumor.
A World Health Organization (WHO) grade 1 meningioma is considered benign, but this designation is an educated guess and the long-term behavior (based on imaging) is the final arbiter.
A highly calcified tumor (seen on a CT scan) is highly suggestive of a benign tumor. Conversely, there are imaging hints of more aggressive meningiomas other than growth rate, such as involving a lot of swelling in the brain around the tumor.
What causes a meningioma?
No one knows.
Do they tend to occur at a typical age or age range?
Usually in adulthood. They are more common in women and very uncommon in children.
Do they grow?
Yes, most of them do grow. Benign just means they don't grow rapidly and they don't [spread] to other parts of the body. They usually grow a couple millimeters a year on average. There are ones that grow faster. Some grow slowly. Others don't grow at all.
When do you treat them, and how?
The reason we treat is if it is large enough and compressing the brain, causing symptoms. If it is compressing the optic nerve, it could cause blindness. Many are in benign locations where they cause no symptoms.
A small tumor in a bad location can cause a lot of symptoms. Some patients have a very large tumor and no symptoms.
If the tumor isn't too big or in some other cases, radiation therapy is better than surgery for some patients.
What is a likely course for Sheryl Crow?
It depends on where it is located and how big [it is]. At her age, it is very likely it is growing.
It's possible she [Crow] will just get radiation treatment. Or if it's not growing, they will probably just follow her with serial MRI scans to be sure it's not growing. She may need treatment later.