Ganglia (ganglion cysts) are gelatinous swellings on the hands and wrists.
Ganglia typically occur in people between the ages of 20 and 50. Women are affected 3 times more often than are men. The most usual place for ganglia to develop is the back (dorsal aspect) of the wrist. Ganglia also develop on the front of the wrist (palmar aspect) and on the back of the finger, a few millimeters behind the cuticle (where they are also called mucous cysts).
Why ganglia develop on the wrist is not known, although they may be related to a previous injury. Ganglia on the back of the finger usually are related to arthritis of the last joint of the finger. However, in most cases, having a ganglion cyst does not mean that arthritis will develop.
Ganglia are firm, round or elliptical sac-like swellings that rise from the skin surface. They contain a clear, gelatinous, and usually sticky material. They are usually painless but occasionally cause discomfort. A doctor can readily make the diagnosis by examining the hand.
Did You Know...
• Hitting a ganglion cyst with a book is not recommended.
Treatment
Some ganglia disappear without treatment, so treatment may not be necessary. However, if they are unsightly, cause discomfort, or continue to increase in size, the gelatinous material inside them can (in 50% of people) be removed successfully by a doctor using a needle and a syringe. Sometimes a corticosteroid suspension is injected afterward to further ease any discomfort. The traditional method of removing a ganglion—placing the hand on a firm surface (such as a table) and hitting the ganglion with a large book—is not advisable. This method may cause injury and is unreliable. In about 50% of people, surgical removal may be necessary. After surgical removal, ganglia recur in about 5 to 15% of people.
Resource: Merck Manual Home Edition