What is a cyst?
A cyst is a sac or pocket in your body filled with fluid, semi-solid material or air. Cysts are common and can form in any part of the body. They can be microscopic or grow to the size of tennis balls or even melons.
Cysts are different from abscesses or boils, which are filled with pus. Most cysts are not cancerous.
Types of cysts
There are hundreds of types of cysts. Different types of cyst form in different parts of the body.
Some of the common types are:
- acne cysts
- Bartholin’s cysts (on the vulva)
- breast cysts
- chalazion cysts (on the eyelids)
- ovarian cysts
- pancreatic cysts
- pilonidal cysts (near your tail bone)
What causes a cyst?
Cysts are caused by blockages that lead to a buildup of fluid or air. The blockages can be due to infection, genetic conditions, inflammatory conditions, parasites or tumours. Some people get cysts around body hairs or piercings for earrings.
Your symptoms will depend on what type of cyst you have and where it is. Most cysts don’t have symptoms, but you may become aware of a lump or bump, especially if the cyst is on or below your skin or it’s painful.
Some cysts cause pain, especially if they grow and cause pressure.
You should see a doctor if you think you have a cyst, because some cysts need treatment and a small proportion of them are cancerous.
Depending on the type of cyst and where it is, your doctor may suggest imaging tests such as an x-ray or ultrasound or a biopsy (taking a small piece of tissue from the body so that it can be tested) to help diagnose it.
The treatment your doctor suggests will depend on the type of cyst, where it is situated in the body, and how painful or uncomfortable it is. Many cysts disappear without needing treatment.
Depending on where it is situated, your doctor may be able to drain a large, painful or uncomfortable cyst with a needle. Very large cysts, or cysts that could be cancerous, may need to be surgically removed.
In some cases, such as polycystic ovarian syndrome, the underlying medical condition that has caused the cysts needs to be treated.
Do not try treating a cyst yourself by squeezing and bursting it.
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Last reviewed: April 2019