A cyst is a sac-shaped structure in the body. Cysts usually are filled with fluid, which may be blood, clear fluid, or pus.

A cyst can be normal, abnormal, or, in rare cases, cancerous. In some cases, a cyst may be drained either with a needle or by cutting it open, or it may be removed entirely.

Current as of: March 12, 2014

Author: Healthwise Staff

Medical Review: Patrice Burgess, MD - Family Medicine & Kirtly Jones, MD - Obstetrics and Gynecology