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Symptoms and Signs of Ganglion Cyst

Doctor's Notes on Ganglion Cyst

A ganglion cyst is a sac-like swelling that arises from the synovium, the tissue that lines a joint or surrounds a tendon. Ganglion cysts can be caused by inflammation of the synovium due to local trauma or injury. They may also arise as early signs of arthritis. Ganglion cysts are most common around the joints of the wrists and ankles.

Signs and symptoms associated with a ganglion cyst include painless, localized swellings of the involved area. There are usually no visible signs of inflammation like redness or warmth. A ganglion cyst behind the knee that can become large is known as a Baker's cyst. This type of ganglion can cause a sense of fullness or tightness in the knee joint.

Medical Author:
Medically Reviewed on 3/25/2019

Ganglion Cyst Symptoms

  • The ganglion cyst usually appears as a bump (mass) that changes size.
  • It is usually soft, anywhere from 1-3 cm in diameter (about .4-1.2 inches) and doesn't move.
  • The swelling may appear over time or appear suddenly, may get smaller in size, and may even go away, only to come back at another time.
  • Most ganglion cysts cause some degree of pain, usually following acute or repetitive trauma, but many are without symptoms, except for their appearance.
  • The pain is usually nonstop, aching, and made worse by joint motion.
  • When the cyst is connected to a tendon, one may feel a sense of weakness in the affected finger.

Ganglion Cyst Causes

The cause of ganglion cysts is not known. One theory suggests that trauma causes the tissue of the joint to break down forming small cysts, which then join into a larger, more obvious mass. The most likely theory involves a flaw in the joint capsule or tendon covering (sheath) that allows the joint connective tissue to bulge out. Chronic damage may cause cells to produce mucin and fluid.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.