Brain Cyst

What is a brain cyst?

A brain cyst or cystic brain lesion is a fluid-filled sac in the brain. They can be noncancer (benign) or cancer (malignant). Benign means that the growth doesn't spread to other parts of the body. A cyst may contain blood, pus, or other material. In the brain, cysts sometimes contain cerebrospinal fluid (CSF). CSF is a clear liquid that bathes and cushions the brain and spinal cord. Some brain cysts begin before birth. 

Even if a brain cyst isn't cancer, it can still cause problems. The cyst may press against brain tissue and cause symptoms, such as headache, vision problems, or nausea. If this happens, you may need surgery to remove the cyst. In some cases, if the cyst is small and not growing and isn't likely to cause symptoms, your healthcare provider may advise watching it instead of surgery. 

There are different types of brain cysts: 

  • Epidermoid cyst. This is also called an epidermoid tumor. Like a dermoid cyst, it forms from a bit of tissue that gets trapped when the brain and spinal cord form. Epidermoid cysts don't contain sweat glands or hair follicle cells. They grow very slowly. These cysts often first appear when a person is an adult.
  • Pineal cyst. This happens on the pineal gland in the middle of the brain. This type of cyst often only shows up during imaging scans done for another reason. Pineal cysts seldom cause problems. If they do grow large, they can sometimes affect vision. They can appear in people of any age.
  • Brain abscess. This happens anywhere in the brain as a single cyst or multiple cysts. Abscesses are often caused by a bacterial infection. They are sometimes caused by a parasite or a fungus.
  • Neoplastic cyst. This is due to a benign or malignant tumor. When a brain tumor starts outside the brain, it is called metastatic.

What causes a brain cyst?

Brain cysts are caused by the building up of fluid in an area of the brain. Brain cysts can form during the first few weeks when a baby is growing in the uterus. Some cysts might form because of a head injury or other trauma to the brain. In other cases, there may be links between a brain cyst and a noncancer tumor or a cancer tumor.

What are the symptoms of a brain cyst?


Symptoms may be different for each person, but can include: 

  • Headache (common)
  • Nausea and vomiting
  • Vertigo or dizziness
  • Hearing or vision problems
  • Trouble with balance and walking
  • Facial pain
  • Seizures (not common)

How is a brain cyst diagnosed?


The process to diagnose a cyst starts with a health history and a physical exam. Your healthcare provider will ask about your symptoms and past health conditions. They may also ask about your family’s health history. The physical exam may include a nervous system exam. Imaging tests may be done to look at the brain. Contrast dye may be used to help show more detail in the images. The tests may include: 



How is a brain cyst treated?

If a brain cyst is causing problems, your healthcare provider may advise removing it with surgery. If the cyst is not causing symptoms and it isn't growing, your healthcare provider may choose to watch it closely with repeated brain scans. Treatment can vary by the type of cyst. For example:

  • If you have an arachnoid cyst, your healthcare provider may puncture the cyst sac and drain the fluid. The fluid drains into the CSF or is pulled out with a needle. If your provider drains the cyst without removing part of the sac or placing a permanent draining tube, the sac may fill with fluid again.
  • If you have a dermoid or epidermoid cyst, your healthcare provider will likely remove it. The complete cyst with its sac will likely be removed. If the cyst isn't fully removed, it may regrow and cause symptoms again after a few years.
  • Pineal cysts often cause no problems. It's often possible to manage these by watching for any changes.

Key points about a brain cyst

  • Brain cysts are fluid-filled sacs that may form in the brain. They can be noncancer (benign) or cancer (malignant).
  • A brain cyst that doesn't cause symptoms will sometimes show up during an imaging scan done for another reason.
  • Even when brain cysts aren't cancer, they may press against brain tissue and cause symptoms. Sometimes a cyst may block the normal flow of CSF. This can cause problems.
  • Your neurologist or neurosurgeon may advise surgically removing the cyst. If the cyst is small and not likely to cause symptoms, your healthcare provider may instead advise watching it to see if it remains stable.

Next steps


  • Before your visit, write down questions you want answered.
  • Ask if your condition can be treated in other ways.
Medical Reviewer: Joseph Campellone MD
Medical Reviewer: Marianne Fraser MSN RN
Medical Reviewer: Raymond Kent Turley BSN MSN RN
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