Cysts are closed capsule or sac-like structures, typically filled with liquid, semisolid or gaseous material - very much like a blister.
Cysts occur within tissue, and can affect any part of the body. They vary in size from microscopic to the size of some team-sport balls - large cysts can displace internal organs.
In anatomy, a cyst can also refer to any normal bag or sac in the body, such as the bladder. In this article, cyst refers to an abnormal sac or pocket in the body that contains either liquid, gaseous or semi-solid substances.
A cyst is not a normal part of the tissue where it is located. It has a distinct membrane and division on nearby tissue - the outer or capsular portion of a cyst is called the cyst wall. If the sac is filled with pus it is not a cyst, it is an abscess.
Contents of this article:
Fast facts on cysts
Here are some key points about cysts. More detail and supporting information is in the main article.
- Cysts are noncancerous and have a sac-like structure that can be filled with fluid, pus, or other gaseous material.
- Cysts are common and can occur anywhere on the body.
- Cysts are often caused by infection, clogging of sebaceous glands or around earrings.
- It is unusual for cysts to cause pain unless they rupture, become infected or inflamed.
- Cysts tend not to disappear on their own without treatment - they can be drained by a medical professional, treated with a cortisonemedication injection or surgically removed.
- Most cysts are benign. However, some cysts may be tumors and possibly malignant.
- Breast cysts are often painful and may be noticeable during a breast examination.
- Kidney and liver cysts may not have any symptoms and go unnoticed until a MRI, CAT scan or ultrasound detects them.
- Aspirated liquid is sometimes examined to investigate if there are any cancerous cells present.
- Some cysts arise as a result of a chronic or underlying medical issue - fibrocystic breast disease or polycystic ovary syndrome.
What causes cysts?
A parasitic cyst - such as a hydatid cyst - formed by the larva of a parasite.
Common causes of cysts include:
- Genetic conditions
- A fault in an organ of a developing embryo
- A defect in the cells
- Chronic inflammatory conditions
- Blockages of ducts in the body which cause a fluid build-up
- A parasite
- Impact injury that breaks a vessel.
Benign and malignant cysts
Most cysts are benign and are caused by plugged ducts or other natural body outlets for secretions. However, some cysts may be tumors and are formed inside tumors - these can be potentially malignant. Examples include keratocysts and dermoid cysts.
On the next page we look at the symptoms of cysts and the common types. On the final page we discuss treatments for cysts.