A cyst is a closed sac having a distinct membrane and developing abnormally in a cavity or structure of the body.
Cysts may occur as a result of a developmental error in the embryo during pregnancy or they may be caused by infections. Cysts may also arise spontaneously with no apparent cause.
Cysts may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst.
Cysts can occur anywhere in the body.
Common types of cyst
- Bronchial cyst (in the airways)
- Dentigerous Cyst (associated with the crowns of non-erupted teeth)
- Ganglion cyst (hand/foot joints and tendons)
- Glial Cyst (in the brain)
- Gartner's Cyst (in vagina and will never show up on an embryology exam)
- Keratocyst (in the jaws, these can appear solitary or associated with the Gorlin-Goltz or Nevoid basal cell carcinoma syndrome. The latest World Health Organization classification considers Keratocysts as tumours rather than cysts)
- Nabothian cyst (cervix)
- Ovarian cyst (ovaries, functional and pathological)
- Paratubal cyst (fallopian tube)
- Pilonidal cyst (skin infection near tailbone)
- Renal cyst (kidneys)
- Radicular cyst (associated with the roots of non-vital teeth)
- Sebaceous cyst (sac below skin)
- Tarlov cyst (spine)
- Vocal fold cyst