Have you ever spotted a small, round bump near the end of your finger, maybe right next to your fingernail? It could be a myxoid cyst, also called a mucous cyst or digital mucous cyst. These bumps are filled with fluid and often show up near the last joint of a finger or toe.
Myxoid cysts are a type of ganglion cysts, but they tend to show up in different places and for different reasons. They are most common in older adults. They are usually harmless but they can sometimes be painful or change how your nail looks and grows.
What is a myxoid cyst?
A myxoid cyst is a smooth, firm, slightly see-through bump. Myxoid cysts are filled with a jelly-like fluid. If the skin over the cyst breaks, this fluid may leak out. Myxoid cysts are not cancerous.
Why do myxoid cysts form?
Myxoid cysts develop mostly because of wear and tear in the joint, especially from osteoarthritis. Arthritis in the knuckle closest to the joint can trigger inflammation, which causes your joint to make more fluid.
“Many people are surprised to learn that they have arthritis and that the cyst is simply extra fluid from the joint,” said Sharon Stanley, MD, a hand surgeon with Banner - University Medicine.
The joint space there is very small. “So this fluid can leak into the tissue around it and create a small bubble or sac under your skin,” Dr. Stanley said.
Many of these cysts have a narrow stalk, or root, that connects them directly to the joint. Because of this connection, these cysts might return if the surface bump is treated without dealing with the root.
What do myxoid cysts look and feel like?
Myxoid cysts are usually small, about the size of a pea, and usually under a half inch. But they can grow larger over time.
If you have a myxoid cyst you might notice:
- A smooth bump near your nail or finger joint
- Clear or jelly-like fluid that leaks out if the cyst bursts
- Nail changes like a groove or dent in the nail directly above the cyst (due to pressure from the cyst on the nailbed beneath the skin surface)
- Skin thinning or redness over the bump
- Tenderness or mild pressure when you move the joint, especially as the cyst grows, although they are often painless
How do myxoid cysts compare to ganglion cysts?
Myxoid cysts are a type of ganglion cyst. Both are fluid-filled sacs caused by inflammation. But they differ in several ways:
- Location: Myxoid cysts usually form near your fingernails or toe joints. Ganglion cysts are commonly found on your wrists, hands, feet or ankles.
- Cause: Myxoid cysts are often related to joint wear and arthritis. Ganglion cysts are generally caused when a joint or tendon gets irritated.
- Appearance: Myxoid cysts are usually small and close to the skin surface. They may affect your nails. Ganglion cysts tend to be rounder and deeper under the skin.
- Structure: Myxoid cysts often have a narrow stalk that connects them to the joint. Ganglion cysts may also connect to a joint or tendon, but the connection is often deeper within the tissue.
Want to learn more about ganglion cysts? Check out our full guide.
When should you see a health care provider?
You do not always need to treat a myxoid cyst, especially if it is small and does not bother you. But it is a good idea to talk to a health care provider if:
- The cyst is painful or swollen
- The area looks red or infected
- Your nail is changing shape
- You are having trouble moving your finger
- The cyst keeps coming back
A health care provider can also help rule out other possible causes of finger bumps, like warts, skin growths or even skin cancer. They can also check for bone spurs.
Don’t be surprised if you hear a health care provider using different phrasing. “Hand surgeons nearly universally call myxoid cysts mucous cysts,” Dr. Stanley said.
What are the treatment options for myxoid cysts?
Depending on the cyst's size and your symptoms, your health care provider may recommend these treatment options:
Home care
- Keep the area clean and protected
- Avoid trying to pop the cyst, since popping it can lead to an infection
- Watch for any changes in size, color or pain level
- Apply ice
- Use compression
- Take anti-inflammatory medications like ibuprofen
- Wrap the fingertip with a bandage if you want to help protect it from getting bumped
In-office treatments
- A health care provider might drain the fluid from the cyst. “This process is called aspiration and involves sticking a needle into the cyst and sucking out the fluid, using numbing medication,” Dr. Stanley said.
- They may use steroid injections to help reduce swelling.
- Sometimes, applying pressure to the cyst can help flatten it.
Surgery
If the cyst is large, painful or keeps coming back, a hand surgeon can remove both the bump and its root or stalk to reduce the risk of it returning. The surgeon may also remove any bone spurs and smooth out nearby joint surfaces if there’s arthritis.
Both the cyst and bone spurs may return even after surgery. And if the joint is very painful because of severe arthritis, just removing the cyst and cleaning the joint may not make the pain better.
If the pain gets too severe, health care providers might recommend joint fusion. This procedure involves fusing the two finger bones into one, so the last knuckle can no longer bend.
“This helps reduce pain because it is the motion that causes discomfort. Many people at this stage already have limited motion because of bone spurs and deformities,” Dr. Stanley said.
Can you prevent myxoid cysts?
While there is no guaranteed way to prevent myxoid cysts, you may be able to lower your chances of getting them or reduce their impact. Since they are often due to arthritis or inflammation, it may help to:
- Rest the joints
- Avoid overusing the joints
- Take anti-inflammatory medication
- Ice the area
- Use protective gear when you work with your hands
- Watch for early signs and get care if you notice new bumps or nail changes
The bottom line
At Banner Health, you can get help from our team of experts, including dermatologists, orthopedic specialists and hand surgeons. They manage cysts and other joint-related issues with a team approach to diagnosis, treatment and follow-up.
Our team can provide personalized care focused on bringing back your comfort and function. If you need answers or peace of mind, schedule a visit with an expert at Banner Health. Get the right care for your hands and joints so they feel better and work well.
