A myxoid cyst is a small, benign lump that occurs on fingers or toes, near a nail. It’s also called a digital mucous cyst or mucous pseudocyst. Myxoid cysts are usually symptom-free.
Most myxoid cysts occur in people between the ages of 40 and 70, but they may be found in all ages. Twice as many women as men are affected.
Myxoid means mucus-resembling. It comes from the Greek words for mucus (myxo) and resemblance (eidos). Cyst comes from the Greek word for bladder or pouch (kystis).
The exact cause of myxoid cysts isn’t known, but there are two basic explanations.
- The cyst forms when the synovial tissue around the finger or toe joint degenerates. This is associated with osteoarthritis and other degenerative joint diseases. Sometimes a small bony growth formed from degenerating joint cartilage (an osteophyte) may be involved.
- The cyst forms when the fibroblast cells in the connective tissue produce too much mucin (an ingredient of mucus). This type of cyst doesn’t involve joint degeneration.
Myxoid cysts are:
- small round or oval bumps
- up to 1 centimeter (cm) in size (0.39 inch)
- firm or fluid-filled
- not usually painful, but the nearby joint may have arthritis pain
- skin-colored, or translucent with a reddish or bluish tinge and often looks like a “pearl”
When a cyst grows over part of the nail it can cause a groove to develop in the nail or it can split the nail. Sometimes it may cause nail loss.
Myxoid cysts that grow under the nail are rare. These can be painful, depending on how much the cyst changes the nail shape.
When you injure a myxoid cyst, it may leak a sticky fluid. You should see your doctor if a cyst shows signs of infection.
Most myxoid cysts aren’t painful. Unless you’re unhappy with the way your cyst looks or it gets in your way, no treatment is necessary. You may just want to keep an eye on the cyst. But be aware that a myxoid cyst rarely shrinks and resolves on its own.
Many possible treatments are available for myxoid cysts, and their pros and cons are well-researched.
In many cases the cyst grows back after treatment. Recurrence rates for different treatments have been studied. Also, some treatment methods may:
- leave scars
- involve pain or swelling
- decrease joint range of motion
If you’re interested in removing your cyst, discuss with your doctor or specialist which treatment might be best for you. Here are treatment possibilities:
- Infrared coagulation.This procedure uses heat to burn off the cyst base. A 2014 review of the literature showed the recurrence rate with this method to be 14 percent to 22 percent.
- Cryotherapy.The cyst is drained and then liquid nitrogen is used to alternately freeze and thaw the cyst. The objective is to block any more fluid from reaching the cyst. The recurrence rate with this procedure is 14 percent to 44 percent. Cryotherapy may be painful in some cases.
- Carbon dioxide laser.The laser is used to burn off (ablate) the cyst base after it’s been drained. There’s a 33 percent recurrence rate with this procedure.
- Intralesional photodynamic therapy.This treatment drains the cyst and injects a substance into the cyst that makes it light-sensitive. Then laser light is used to burn off the cyst base. A small 2017 study (10 people) had a 100 percent success rate with this method. There was no cyst recurrence after 18 months.
- Repeated needling.This procedure uses a sterile needle or knife blade to puncture and drain the myxoid cyst. It may need to be done two to five times. The cyst recurrence rate is 28 percent to 50 percent.
- Injection with a steroid or a chemical that shrinks the fluid (sclerosing agent).A variety of chemicals may be used, such as iodine, alcohol, or polidocanol. This method has the highest recurrence rate: 30 percent to 70 percent.
Surgical treatments have a high success rate, ranging from 88 percent to 100 percent. For this reason, your doctor may recommend surgery as a first-line treatment.
Surgery cuts the cyst away and covers the area with a skin flap that closes as it heals. The size of the flap is determined by the size of the cyst. The joint involved is sometimes scraped and osteophytes (bony outgrowths from the joint cartilage) are removed.
Sometimes, the surgeon may inject dye into the joint to find (and seal) the point of fluid leakage. In some cases, the flap may be stitched, and you may be given a splint to wear after surgery.
In surgery and in nonsurgical methods, scarring that cuts the connection between the cyst area and the joint prevents more fluid from leaking to the cyst. Based on his treatment of 53 people with myxoid cysts, one researcher has argued that the scarring can be accomplished without the need for cyst removal and a skin flap.
You can try treating your cyst at home by using firm compression every day for a few weeks.
Don’t puncture or try to drain the cyst at home because of infection risk.
There’s anecdotal evidence that soaking, massaging, and applying topical steroids to myxoid cysts may help.
Myxoid cysts aren’t cancerous. They’re not contagious, and they’re usually symptom-free. They’re often associated with osteoarthritis in fingers or toes.
Many treatments are available, both nonsurgical and surgical. Recurrence rates are high. Surgical removal has the most successful outcome, with the least recurrence.
If your cyst is painful or unsightly, discuss potential treatments and outcomes with your doctor. See your doctor right away if your myxoid cyst has signs of infection.