A ganglion cyst is a fluid-filled swelling that develops near a joint or a tendon. The cyst can range from the size of a pea to the size of a golf ball.
Ganglion cysts look and feel like a smooth, soft lump under the skin. They are made up of a thick, jelly-like fluid, called synovial fluid, which surrounds joints and tendons to lubricate and cushion them during movement.
Ganglions can occur alongside any joint in the body, but are most common on the wrist (particularly the back of the wrist), hand and fingers.
Ganglions are generally harmless, but they can sometimes be painful, especially if they are next to a nerve. If they do not cause any pain or discomfort, they can be left alone and may disappear without treatment, although this can take a number of years.
It is not clear why ganglions form, but they may be related to ageing or injury to the joint or tendon. They occur when the synovial fluid that surrounds a joint or tendon leaks out and collects beneath the skin.
Treatment is usually only recommended if the cyst causes pain or affects the range of movement in a joint.
The two main treatment options for a ganglion cyst are:
draining fluid out of the cyst with a needle and syringe (the medical term for this is aspiration)
cutting the cyst out by way of surgery
Most clinical commissioning groups (CCGs) do not fund treatment for ganglion cysts unless they cause significant pain or disrupt daily activities.
If you want to have a cyst removed for cosmetic reasons, you will probably have to pay for private treatment.
Aspiration is carried out under local anaesthetic (where the area is numbed), usually in the outpatient department of your local hospital or GP surgery.
The skin over the lump is cleaned and numbed with a small local anaesthetic injection. Your doctor will remove as much of the contents of the ganglion as possible with a needle and syringe.
The area is sometimes also injected with a dose of steroid medication to help prevent the ganglion returning, although there is no clear evidence that this reduces the risk of recurrence.
After the procedure, a plaster is placed over the small hole in your skin, which can be removed about six hours after the procedure.
Aspiration is a simple and painless procedure and you will be able to leave the hospital or surgery straight afterwards. It is often the first treatment option offered for ganglion cysts as it is less invasive than surgery.
However, around half of all ganglion cysts treated using aspiration will return at some point. If a cyst does return, surgery may be necessary.
There are two ways that surgery can be used to remove a ganglion cyst:
open surgery – where the surgeon makes a medium-sized cut, usually about 5cm (2 inches) long, over the site of the affected joint or tendon
a type of keyhole surgery where smaller incisions are made and a tiny camera, called an arthroscope is used by the surgeon to look inside the joint. Using the arthroscope as a guide, they then pass instruments through the incision to remove the cyst
Both techniques can be performed under either local or general anaesthetic, depending on where the ganglion is, which anaesthetic you would prefer and what your surgeon thinks is best.
Having a local anaesthetic means that you will be awake but will not feel any pain. Having a general anaesthetic means that you will be asleep during the operation.
Open or keyhole surgery?
Both techniques are equally effective in removing the cyst and reducing the risk of it returning.
Keyhole surgery tends to cause less pain after the operation, butwaiting times are often longer.
After the operation
The surgeon will stitch up the wound and a bandage will be placed over the area. This helps keep the area clean, reducing the risk of infection, and safe from any accidental bumps. The wound is not usually painful, but you will be given painkillers to take if you feel any discomfort after the operation.
If the cyst was removed from your wrist or hand, you may need to wear a sling for the first few days. This will help keep your arm safe from any accidental knocks and may help reduce swelling and discomfort. Move your fingers regularly to help keep the joints flexible.
Surgery to remove a ganglion cyst will leave a scar that can occasionally be thick and red. For some people, the skin around the scar remains numb after the operation.
It is likely that you will experience some bruising in the area after your operation, but this should fade quickly. There is also a small possibility of temporary stiffness, swelling or pain afterwards. This may be caused by a minor infection that can be treated using antibiotics. Lasting pain or stiffness may need further treatment with physiotherapy.
How much time you need to take off work after surgery to remove a ganglion cyst will largely depend on your job. If you job involves manual labour, you may need to take several weeks off. Most people are able to start driving again about two to four weeks after surgery.
Having a ganglion cyst removed is a minor procedure, so complications are rare and seldom serious. However, a small number of people experience permanent stiffness and pain after surgery.
If you have the operation under general anaesthetic, there is also a very small risk of complications to your heart and lungs. Pre-assessment tests before surgery should make sure that your risks are as low as possible.
There is always a chance that a ganglion cyst will come back after treatment. It's estimated that between one and four in every 10 cysts that are surgically removed will return. The cyst can be removed again with a good chance of success the second time round, although having further surgery does increase the risk of complications, such as damage to nearby nerves.
Illustration of a ganglion cyst
Will the cyst disappear if I hit it with a heavy object?
In the past, the tradition was to bash a ganglion with a heavy book to break the cyst open and release its contents. This was a drastic remedy and is no longer recommended.