Ependymoma is a very rare type of tumor that starts in the brain or spinal cord. It can happen in both children and adults although it is more common in children and rare after the age of 40.
Your brain and your spinal cord make up your central nervous system (CNS). Ependymoma is a primary CNS tumor. This means that it starts in the brain or spinal cord rather than starting somewhere else in the body and spreading to the brain.
Ependymoma is a kind of glioma. This means it starts in support cells (glial cells) of the brain. Ependymomas start when certain types of glial cell called ependymal cells start to grow out of control. These cells line the ventricles of the brain. The ventricles are the chambers that contain the cerebrospinal fluid (CSF) that bathes and cushions the brain and spinal cord. Ependymomas can spread when the CSF carries ependymoma cells to other places in the brain or spinal cord. These tumors rarely spread beyond the CNS to other parts of the body.
There are different types of ependymomas. Most tend to be slow-growing tumors. They're given a grade based on how different the tumor cells are compared to normal ependymal cells. A scale of 1 to 3 and Roman numerals are used: I (1), II (2), or III (3). Grade I is the slowest-growing ependymoma, Grade III is fast-growing. These are the major types:
- Subependymoma (grade I). This is a slow-growing tumor near the ventricles. It's more common in adults than children. Many times, it doesn't cause symptoms.
- Myxopapillary ependymoma (grade I). This is a slow-growing, lower spinal cord tumor most common in male adults.
- Classic ependymoma (grade II). This is a somewhat faster-growing tumor in both children and adults. There are many subtypes.
- Anaplastic ependymoma (grade III). This is a fast-growing cancer tumor often in the base of the brain and rarely in the spinal cord. It tends to spread into nearby parts of the brain and spread to other parts of the brain through the CSF. These tumors tend to come back (recur) after treatment.
Some grade I ependymomas are not called cancer because they grow slowly and don't spread. Still, any tumor in the brain, no matter how small, may cause problems by pressing against parts of the brain and causing symptoms. An ependymoma that causes symptoms will be treated, even if it's not cancer. Recently these tumors are now classified based on where they arise, how they appear under the microscope (histology) and the molecular characteristics of the tumor.