Are Ependymomas Cancer? Symptoms and Prognosis of This Intracranial Tumor
Ependymomas are rare type of brain tumors that develop from the ependymal cells, which line the ventricles of the brain. They are cancerous. WHO classifies them as low-grade, medium-grade and high-grade depending upon the aggressiveness of cancer cells. Patient usually visits the doctor only after the appearance of symptoms like headaches and vomiting.
Cause of Symptoms
They occur due to increased pressure within the skull. This is caused by a blockage in the ventricles of the brain that leads to a build-up of cerebrospinal fluid around the tumor itself. They may be associated with the formation of a cyst.
What Is a Cyst?
Cyst refers to any fluid filled cavity. Unlike solid tissue, it’s a balloon-like tissue layer that contains fluid. Tumors are often associated with cysts.
Choroid cysts are usually found within the ventricles in young adults. They may cause hydrocephalus(an enlarged part of skull) by obstructing the fluid passage.
Seizures May Occur
Any lesion (tumor, cyst, hemorrhage) in the brain may lead to seizures by disrupting the normal electrical discharges from tissue membrane. Lesions press upon the surrounding tissues, hence interfering with the electrical activity of the brain. They may induce abnormal firing of electric signals from a particular area thereby causing seizures. These abnormal signals are detected on EEG (Electroencephalogram).
Making a Diagnosis
Contrast MRI is done for diagnosis. MRI is considered more sensitive than CT scan for detecting intracranial masses. Enhancement refers to the increased signal by using a contrast agent e.g. gadolinium. It increases the diagnostic capability of MRI. For instance, Gadolinium is a contrast agent that does not cross the intact blood-brain barrier. But when the blood-brain barrier is absent or deficient, gadolinium enters the interstitial space to produce enhancement (increased signal) on MRI images. The enhancement shown by many lesions (e.g. tumors) help in their diagnosis. Enhancement margins also aid in judging the extent of tumor. Non-enhancing areas are those that are not ‘showing up’ prominently from rest of the brain tissue.
The final diagnosis rests on the brain biopsy. If it proves to be an ependymoma, then a myelogram may be required to rule out the spread to the spinal cord. The lesion may require surgical removal later on.
