Brain cyst guide


Icon editWhat is a brain cyst?

A brain cyst is a spherical growth located in the brain. The globe is usually filled with cerebrospinal fluid. However, some cysts may contain blood, pus, hair follicles, or skin cells. Generally, cystic formations are not considered tumours and are usually not cancerous.

What is a brain cyst?Cysts can be of various types and are classified according to the site of origin and the material they contain. The most common are listed below:

  • Arachnoid cysts make up about 1% of all intracranial formations and look like sacs filled with cerebrospinal fluid. Most arachnoid cysts are congenital but may occur after head trauma, meningitis, or brain surgery.
  • Colloidal cysts are gel-filled cysts. Often begins to form during pregnancies. Usually, these cysts remain the same size for a long time until adulthood, when, due to their size, they begin to block the outflow of cerebrospinal fluid, which causes severe headaches.
  • Dermoid cysts are a rare type. They are formed when a few skin cells get trapped while the brain and spinal cord are developing in the fetus. These cysts may even contain sweat glands or hair follicle cells and often appear in children.
  • Epidermoid cysts are so-called epidermoid tumours. It is formed from a piece of tissue captured during the brain and spinal cord formation. They are growing very slowly and usually first appear in adults.
  • Pineal cysts occur in the middle of the brain and rarely cause problems. However, if it becomes large, it can sometimes affect vision. This kind of cyst appears at any age.
  • Brain abscess occurs anywhere in the brain in the form of single or multiple cysts. They are usually caused by bacterial infections, parasites, or fungi.
  • Neoplastic cysts appear due to a benign or malignant tumour. If a brain tumour starts outside the brain, it is called metastatic.

Risk factors for most cystic formations in the brain are unknown. It is believed that most neoplasms are caused by intrauterine malformations and may be hereditary. Cysts can also be caused by traumatic brain injury. Hormonal changes may be the cause of the development of a pineal cyst. The reason for such change are injuries, various diseases, infections and other diseases.

Icon microscopeDiagnostic tests

Symptoms usually depend on where in the brain the cyst grows. Some cysts are "silent" (cause no symptoms) until they become sizable. In some cases, the patient may have problems related to the area of ​​the brain where the cyst is enlarging. In other cases, symptoms may be related to a blockage in the normal flow of cerebrospinal fluid, which cause increased brain pressure (intracranial pressure). For each person, symptoms may be different, but often, they include:

  • Headache (general);
  • Nausea and vomiting;
  • Vertigo or dizziness;
  • hearing or vision problems;
  • Difficulties with balance and walking;
  • facial pain;
  • Seizures (rare).

Very often, cystic formations are discovered by chance during an examination made for another reason. Neurological or neurosurgical examinations begin with a history and physical assessment. The neurologist may also ask about the family's medical history. Next, a physician may perform imaging tests to check the brain. Contrast dye is often used to show more detail in images. Tests may include:

  • CT scan is an imaging test which uses x-rays and a computer to produce detailed images of the body. Usually, a scan of the brain and spinal cord is done.
  • MRI scan uses large magnets and a computer to create body images. For example, an MRI of the brain and spinal cord may be done to get more information about the cyst and nearby tissues. A doctor may repeat the scan later to see if the cyst is growing.

Icon doctorTreatment methods

Most cystic formations can be observed clinically without any treatment. However, there are cases when the cyst grows, and its treatment becomes critical. Since a cystic mass is usually a sac filled with fluid, the treatment goal is to remove the liquid and the membrane. The important is to remove the walls of the cyst, to prevent further filling in. This procedure reduces pressure and relieves symptoms.

Treatment is regulated by the location, size, and type of cyst. For instance, people with a small brain cyst that does not change or cause pressure on the brain may not need surgery. Instead, neurosurgeons can monitor the enlargement of the mass with routine imaging techniques.

Surgery is recommended for patients to alleviate symptoms and prevent neurological damage. Surgical removal is usually performed with a craniotomy.

  • Craniotomy for fenestration - in this procedure, the surgeon opens the skull to get to the cyst and opens it.
  • Drainage during this procedure, the neurosurgeon pierces the cyst with a small needle to drain the fluid. This approach is simple and fast, but the likelihood of the cyst returning is high.

Icon plusNew treatment options

Based on the type, size and location of the cyst, new procedures and methods are being developed and proposed:

  • Endoscopic techniques contain cyst drainage or the opening of a "window" in it. Endoscopic procedures use a little, thin tube with a camera and tiny instruments. In addition, these minimally invasive methods use smaller incisions. As a result, the patient will need less time to recover than with traditional surgery.
  • Shunting - a peritoneal shunt is inserted into the cyst. A shunt is a medical device that consists of catheters (thin tubes) and a valve. Fluid drains through the tubes into the abdominal cavity (belly).

Icon chartStatistics and prognosis

Generally, most brain cysts are benign and do not require surgical removal. However, the neurosurgeon will select and offer the best option if a surgical approach is needed for specific indicators.

Many brain growths are congenital, but sometimes they can indicate an underlying medical condition such as cancer or infection. However, most people with cysts have a good prognosis with complete surgical removal. And AiroMedical specialists will help you choose the best treatment tactics.

The National Institutes of Health (NIH) laboratories conduct a lot of research on brain abnormalities and nervous system disorders. In particular, the causes of arachnoid cysts and their impact on the human condition, including on children, are being investigated.

Observation has shown that approximately 1% of children with blunt head trauma develop arachnoid cysts. In 35%, the cyst causes signs of altered mental status (drowsiness, slow response, repetitive questions); 50% have headaches; 24% note the presence of vomiting; 37% have a history of loss of consciousness.

Statistics and prognosis

If not treated, arachnoid cysts can cause irreversible severe neurological damage when the cyst expands or bleeds damaging the brain or spinal cord. Symptoms usually disappear or improve with treatment.


  1. John Wiley & Sons: Children With Arachnoid Cysts Who Sustain Blunt Head Trauma: Injury Mechanisms and Outcomes
  2. HealthJade: Arachnoid cyst
  3. WebMD: What Are Arachnoid Cysts?
  4. Canadian Cancer Society: Brain and spinal cord cysts
  5. Healthline Media UK: What to know about cysts
  6. American Brain Tumor Association: Cysts
  7. National Institutes of Health (NIH): Arachnoid Cysts