What is a Brain Cyst?
A brain cyst is a fluid-filled sac that forms in the brain. They can be malignant (cancerous) or benign (noncancerous). Unlike tumors, most brain cysts are benign, but they can still cause symptoms if they grow large enough to put pressure on surrounding brain structures, leading to neurological issues. They can be congenital (present at birth) or develop later in life.
Types of Brain Cysts
The common types of brain cysts are:
- Arachnoid Cyst – The most common type, filled with cerebrospinal fluid (CSF). Usually congenital and found between the brain and arachnoid membrane.
- Colloid Cyst – Found in the third ventricle, can obstruct cerebrospinal fluid (CSF) flow, leading to hydrocephalus.
- Dermoid & Epidermoid Cysts – Slow-growing cysts that contain skin, hair, or other tissue.
- Pineal Cyst – Develops in the pineal gland, often asymptomatic and found incidentally during scans done for another reason.
Causes of Brain Cysts
Brain cysts can be caused by various factors, including congenital defects during fetal development, brain injury or trauma, infections like meningitis, blockage of cerebrospinal fluid (CSF) flow, or the presence of brain tumors that lead to fluid accumulation. Some cysts may form due to genetic conditions or abnormal tissue growth in the brain. In most cases, the exact cause of a brain cyst is unknown.
Symptoms of Brain Cysts
Symptoms of brain cysts are typically noted when the cyst grows and presses on brain tissue. These may include:
- Headaches
- Nausea & vomiting
- Balance and coordination issues
- Vision or hearing problems
- Cognitive or memory problems
- Seizures
- Weakness or numbness
- Behavioral changes
- Developmental delays
- Hemiparesis (weakness or paralysis on one side of the body)
Diagnosis of Brain Cysts
The diagnosis of a brain cyst typically begins with a neurological evaluation based on symptoms such as headaches, seizures, or vision problems. Imaging studies are the primary method for detecting and assessing brain cysts. A CT (Computed Tomography) scan provides detailed images of the brain’s structure, while an MRI (Magnetic Resonance Imaging) scan offers a more precise view of soft tissues and fluid-filled spaces, helping to differentiate between cysts and other abnormalities like tumors. In some cases, contrast-enhanced imaging is used to determine if the cyst has solid components or connections to blood vessels. If the cyst is suspected to be related to an infection or tumor, additional tests such as blood work, cerebrospinal fluid (CSF) analysis, or a biopsy may be required. Regular imaging follow-ups are often recommended for asymptomatic cysts to monitor their growth and impact on brain function.
Treatment for Brain Cysts
Treatment for brain cysts depends on the type, size, and whether they are causing symptoms. For asymptomatic cysts, observation with regular MRI or CT scans is often sufficient to monitor for any changes. If the cyst is large or symptomatic, treatments may include surgical drainage using a needle or catheter to remove the fluid, though there is a risk of recurrence. Endoscopic fenestration is a minimally invasive procedure where an opening is made to allow fluid to drain into surrounding areas of the brain, reducing pressure. In some cases, surgical removal of the cyst through a craniotomy may be necessary to prevent further complications, especially if the cyst is causing significant neurological symptoms. For cysts causing fluid buildup, a shunt may be placed to divert excess fluid to another part of the body, such as the abdomen, to relieve pressure on the brain. The choice of treatment depends on the cyst's characteristics and the patient’s overall health.
