A cyst is a closed sac having a distinct membrane and division from the nearby tissue. It may contain air, fluids, fat, or semi-solid material. Once formed, the cyst may go away by itself or may have to be removed during surgery. Many cysts in the body are benign (also known as functional cysts), which are the result of plugged ducts or other natural body outlets for secretions.

What are the types of cysts?

There are hundreds of types of cysts that can arise in the body. Here are some of the more well-known types of cysts:

-Cysts in the breast can be part of benign proliferative ("fibrocystic") disease (also known as fibrocystic breast disease).

-Cysts within the thyroid gland.

-Sebaceous cysts of the small glands in the skin.

-Epidermal cysts of the skin, sometimes known as epidermal inclusion cysts.

-Bartholin cysts, which are formed by enlargement of the small glands near the vaginal opening.

-Pilonidal cysts, which are a special kind of cyst that occurs in the cleft between the buttocks. This type of cyst often will become infected, and require incision and drainage.

What is the treatment for a cyst?

The treatment for a cyst depends upon the cause of the cyst as well as its location. Cysts that are very large and result in symptoms due to their size may need to be surgically removed. Cysts that are in an uncomfortable location for the patient may also require surgical removal. Sometimes the fluid contained within a cyst can be drained, or aspirated, by inserting a needle or catheter into the cyst cavity, resulting in collapse of the cyst. Radiologic imaging may be used for guidance in draining (aspirating) cyst contents if the cyst is not easily accessible.

Cysts that are infected or abscessed may require a procedure known as incision and drainage, where the cyst is cut open under a local anesthetic, and then the infectious material is drained out of it. The area is then cleaned, bandaged, and left open to heal on its own. Later on, the cyst may need to be surgically excised to prevent a recurrent infection.

If there is any suspicion that a cyst is cancerous, the cyst is generally removed by surgery or a biopsy is taken of the cyst wall (capsule) to rule out malignancy. In certain cases, aspirated fluid from a cyst can be examined under a microscope to determine if cancer cells are present in the cyst.