This article is about cysts in the body. For the ICAO airport code CYST, pathophysiology of cystic fibrosis pdf St.
For hard-shelled resting stages of some small organisms, see Microbial cyst. A cyst is a closed sac, having a distinct membrane and division compared with the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst.
Once formed, sometimes a cyst may resolve on its own. When a cyst fails to resolve, it may need to be removed surgically, but that would depend upon its type and location. Cancer-related cysts are formed as a defense mechanism for the body, following the development of mutations that lead to an uncontrolled cellular division. The body encapsulates those cells to try to prevent them from continuing their division and to try to contain the tumour, which becomes known as a cyst.
That said, the cancerous cells still may mutate further and gain the ability to form their own blood vessels, from which they received nourishment before being contained. Once that happens, the capsule becomes useless and the tumour may advance from benign to a cancer. Some are dysplastic or metaplastic.