A ganglion is a fluid-filled lump which can occur near joints or tendons. It is not a cancer. It is most commonly found on the wrist or hands. It is usually harmless but can be unsightly. Often, no treatment is needed. If required, a ganglion can be removed by a small operation.
What is a ganglion?
A ganglion is a small swelling that contains a thick jelly-like material. It looks and feels like a smooth lump under the skin. It is not fully understood how it occurs. In some cases they occur after an injury but in most there is no obvious cause.
A ganglion is usually attached to a joint or tendon, and the fluid inside is a thicker version of the fluid which 'lubricates' the joint and tendon sheaths (synovial fluid).
The most common site for a ganglion to be found is on the back of the wrist. It can also occur on the other side of the wrist, on the hand, and on the top of the foot. Other sites of the body are affected less commonly.
What are the symptoms of a ganglion?
The main symptom is one of swelling. Ganglions (sometimes called ganglia) usually are very smooth and round. Their size can vary from being very small (pea-sized) to being larger (plum-sized). Larger ganglions can sometimes be unsightly. They can sometimes be painful, particularly if they lie next to a nerve. They never spread to other areas of the body.
Although they are present all the time for most people, they can be present intermittently. In many people, they disappear completely over time without any treatment.
Usually no tests are required and your doctor can tell if the lump is a ganglion just by examining you. Very occasionally if the diagnosis is not clear, a scan such as an ultrasound scan or MRI scan may be needed.
What is the treatment?
If a ganglion does not cause symptoms it is best just to leave it alone. However, many people prefer to be rid of them, especially if they are causing pain or discomfort.
Many people have heard of the traditional cure. That is, to smash them with a heavy book (tradition holds it to be the family bible). This bursts the cyst under the skin. The fluid is then absorbed into the bloodstream. In some people (who are brave enough) this works well, but there is a high chance of it coming back (recurring), as the walls of the cyst can reform. It can be an instant cure for some but there is a risk of damage to other parts of the hand.
In some cases it is possible to suck out (aspirate) the fluid with a needle and syringe. If the jelly-like fluid is very thick this may not work. Also, if it does work, there is a chance that the cyst will recur, as the wall of the cyst is not removed, and the fluid may form again to refill the ganglion. However, in some people it cures the problem. As it is quite easy for a doctor to do, this is often attempted first.
Surgical removal of the ganglion is the most successful cure. This is a relatively minor operation. This is the treatment that is most likely to be permanent. However, in some cases after a ganglion is removed, one recurs again at the same site.
Further reading and references
; British The British Society for Surgery of the Hand (BSSH)
; Dorsal wrist ganglion: Current review of literature. J Clin Orthop Trauma. 2014 Jun5(2):59-64. doi: 10.1016/j.jcot.2014.01.006. Epub 2014 Jun 3.
; Primary Care Dermatology Society, August 2013
; Ganglion cysts of the wrist: pathophysiology, clinical picture, and management. Curr Rev Musculoskelet Med. 2008 Dec1(3-4):205-11. doi: 10.1007/s12178-008-9033-4. Epub 2008 Aug 26.
; British Society for Surgery of the hand