Colloid cyst; all you need to know about this benign brain tumour

A colloid cyst is a benign brain tumour, which means it’s non-cancerous. These cysts don’t spread, but they do slowly grow in size. They are small fluid-filled sacs located in or around the lateral and third ventricle of the brain.

Due to its location in the ventricles, a colloid cyst can sometimes cause a blockage of cerebral spinal fluid (CSF). CSF protects and cushions the brain and spinal cord and if the flow of CSF is interrupted because a cyst is disrupting the circulation of fluid, it can cause a person to develop hydrocephalus (excess CSF in the brain).

There is no definite cause as to why a colloid cyst develops but it’s thought to be present from foetal development and tend to grow as a person grows into adulthood. Mr Christopher Chandler talks about the symptoms of a colloid cyst and how we can treat one.

What are the symptoms of a colloid cyst?

Most of the time, colloid cysts do not present with symptoms as they grow slowly and the brain has time to get used to the cyst being there.

A colloid cyst will start to cause symptoms when it begins to block the CSF flow that circulates around the brain and spine. This leads to hydrocephalus.

Symptoms of hydrocephalus will include:

• Headaches
• Vomiting
• Visual disturbances
• Memory problems
• Loss of consciousness and coma, in extreme cases

How is a colloid cyst diagnosed?

Colloid cysts are usually diagnosed incidentally. This means that diagnosis is almost always by accident, perhaps when a patient is having a scan for different reasons like for a headache. This is because in the early stages of growth there are often no symptoms until the cyst is so big that it blocks the flow of spinal fluid.

If your doctor suspects your symptoms are being caused by something in the brain, they will recommend the patient to have an MRI scan. This scan will capture images of the brain and spinal cord and will be able to identify colloid cysts. This is the quickest way to diagnose a colloid cyst, as the doctor is able to see the imaging almost immediately after the scan is performed.

How are colloid cysts treated?

Treatment for a colloid cyst will differ from person to person as it all depends on the age of the patient, location, size and severity of the cyst and if it is causing CSF blockage.

If a colloid cyst causes no symptoms, is small and is not affecting the patient’s life, then the doctor may recommend that it be monitored and hold off on any treatment. There is not a good enough reason to operate on the patient if the cyst is not affecting the brain. The doctor will monitor the cyst with a yearly MRI scan. If the cyst is growing in size and the patient starts to present with symptoms, surgical removal may be an option. If not, the cyst will continue to be monitored.

If the cyst is interrupting the natural CSF flow of the brain and causing hydrocephalus then surgical intervention will be necessary. This will be in the form of an endoscopic craniotomy, a minimally invasive technique. The cyst will be carefully drained and then resected from the brain. If the hydrocephalus does not resolve, a shunt device may have to be inserted to drain the excess fluid from the brain.

If you are experiencing any of the symptoms mentioned above, you are advised to visit your doctor who may recommend you to see a neurosurgeon if they believe your symptoms are related to the brain.