Tumor Types > Ependymomas
The brain is hollow. Within the brain are cavities called ventricles where the cerebral spinal fluid (CSF) is produced and contained, circulating around the brain and spinal cord. The ventricles are lined with a special type of cell - the ependymal cell. These cells can grow in an uncontrollable and abnormal way and form a tumor, called an ependymoma.
Ependymomas usually begin in the walls of the ventricles. Since the fluid in the ventricles offers no resistance to their growth, most ependymomas grow as a mass in the ventricle. Eventually the mass fills the ventricular cavity, obstructing the flow of ventricular fluid. (Note: inside the brain the fluid is called ventricular fluid; outside the brain it is called spinal fluid. The fluid is trapped within the ventricles, causing part of the ventricular system to balloon out which raises the pressure inside the patient's head. In addition, epndymomas of the third and fourth ventricles can obstruct the flow of fluid from the lateral ventricles, causing hydrocephalus. Both the trapped part of the ventricular system and untreated hydrocephalus can result in headaches, paralysis and eventually coma and death.
Ependymomas can also spill cells into the spinal fluid, a means of metastasis as the cells travel with the spinal fluid and deposit themselves anywhere the CSF goes. They can then form another tumor mass - in another part of the ventricular system - at the base of the brain or within the spine.
As with any glioma, ependymomas can be low grade or high grade. Low grade ependymomas grow as a solid mass in part of the ventricle and usually do not seed the spinal fluid with tumor cells. Furthermore, low grade ependymomas don't invade into the brain and can be cured by surgery.
High grade ependymomas tend to drop cells into the ventricular and spinal fluid which then form distant metastatic tumors. They can invade the surrounding brain tissue by mobile cells to form solid tumor masses within the substance of the brain. These can be highly malignant and are not curable by surgery, radiation or chemotherapy. Treatment may buy some time but the tumor will usually recur.
Diagnosis
Ependymomas do not usually produce symptoms until they have obstructed part of the ventricular system. Ventricular fluid collects upstream of the trapped part of the ventricle, unable to get past the tumor. This results in the ballooning part of the ventricle to act as a mass in the brain, inhibiting the function of nearby brain structures. Depending on the location, the ependymoma can cause a loss of part of the visual field, difficulty speaking, memory problems, weakness in the opposite side of the body and, of course, headaches due to elevated intracranial pressure. The hydrocephalus,(an obstructed ventricular system), will cause more headaches, as well as the possibility of double vision and difficulty walking.
The actual diagnosis of an ependymoma is made at surgery when a piece of tissue is provided for analysis by a neuropathologist. Further diagnostics are done by computed tomography (CAT scans) or magnetic resonance imaging (MRI). Contrast enhancement in either of these tests shows the tumors better. An enhancing tumor within the ventricular system is frequently (but not always) an ependymoma.