What Is It?
A colloid cyst is a benign brain cyst which typically occurs in the middle of the brain in an area called the 3rd ventricle, one of the fluid filled spaces within the brain. These cysts are not really tumors in the sense that they do not tend to continue to grow in size. They do not spread to other parts of the body. They consist of a thin cyst wall filled with soft material.
It is not known what causes this type of cyst. They may be congenital malformations which are present from birth.
What Types of Symptoms Are Typical?
Most commonly patients with a colloid cyst are asymptomatic and do not know they have the cyst until it is found incidentally. In other words, they receive an MRI or CT scan for another reason, revealing the cyst.
In many patients, a history of headache may present. Because there are many causes of headache, most benign, it is not always clear if these headaches are caused directly by the colloid cyst.
Because of the location of the cyst, at the front, top of the 3rd ventricle, it is in a position that can obstruct the normal flow of fluid from other fluid filled spaces in the brain, the lateral ventricles. Large cysts sometimes can be associated with obstruction which can lead to increased pressure inside the brain and enlargement of the ventricles, a condition know as hydrocephalus. If a patient presents with hydrocephalus they may complain of headache, and nausea and vomiting. If severe, it can lead to a deterioration in the level of consciousness and eventually coma.
These cysts are sometimes blamed for sudden death. While this appears to be a very rare complication of a colloid cyst, it happens very infrequently, presumably from acute obstruction and acute hydrocephalus.
How Is The Diagnosis Typically Made?
Most commonly, whether a patient presents with symptoms or is asymptomatic, the cyst is demonstrated on an imaging study of the brain, either a CT scan
or MRI scan
While most masses in the brain should be confirmed by pathology before making a definitive diagnosis, to distinguish it from other types of tumors, in the case of colloid cysts the appearance on MRI is generally very typical and there is not much question as to the correct diagnosis. If a patient does undergo surgery, pieces of the cyst will generally be sent to a pathologist to confirm that it is consistent with a colloid brain cyst and that there is no evidence of another type of tumor.
What Are Some Common Treatments?
Some patients will opt for conservative treatment without surgery and will simply follow-up with MRI's to be sure it is not growing or changing. However, some patients, particularly if they are symptomatic, will undergo surgery to remove the cyst. The goal is to drain the cyst and remove as much of the wall of the cyst as possible so that it does not recur. This type of procedure is done in several ways. Traditionally it is done with an open procedure which opens the ventricles to access the cyst. More recently some surgeons have used an endoscope to access the ventricles through only small bur holes in the skull. They then remove the cyst through the endoscope with special instruments for this purpose.
Each patient is different and therefore each should consult their own treating physicians regarding the most appropriate treatment options for their specific case.
Return to the Brain Tumor page
from the Colloid Cyst page.
Return to the Nervous System Diseases home page.
This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.