Mucous Cysts on the Finger: What They Are and When to Remove Them

You’ve noticed a small, firm, translucent bump on the back of your finger near the nail. It may have appeared, gone away, and come back. Maybe it’s caused a groove or ridge in your fingernail. This is most likely a mucous cyst (also called a myxoid cyst or digital mucous cyst)—a common condition related to arthritis of the finger’s last joint.

What Is a Mucous Cyst?

A mucous cyst is a type of ganglion cyst that forms at the distal interphalangeal (DIP) joint of the finger—the last joint before the fingertip. It arises from the joint capsule and is almost always associated with underlying osteoarthritis (bone spurs) at the DIP joint. The cyst contains thick, jelly-like fluid, similar to joint fluid.

Symptoms

• A small (pea-sized), firm, translucent or skin-colored bump on the back of the finger between the DIP joint and the nail

• The cyst may fluctuate in size—enlarging and shrinking over time

• Nail deformity: a longitudinal groove or ridge in the nail, caused by the cyst pressing on the germinal matrix (nail-producing area)

• Mild tenderness or discomfort, especially with direct pressure

• Occasionally the cyst ruptures spontaneously, draining clear fluid
  

  

  
  

Why Should You See a Hand Surgeon?

While mucous cysts are benign, there are important reasons not to ignore them:

• Infection risk: The skin over the cyst is often very thin. If the cyst ruptures (or if you try to pop it), bacteria can enter the DIP joint, causing septic arthritis—a serious infection that requires emergency surgery.

• Nail deformity: Prolonged pressure on the germinal matrix can cause permanent nail changes

• Pain and interference with finger use

Important: Do NOT puncture, squeeze, or attempt to drain a mucous cyst at home. This risks joint infection.

Treatment

Observation

Small, asymptomatic cysts that are not causing nail deformity can be observed. They occasionally resolve spontaneously.

Surgical Excision

Definitive treatment involves surgically removing the cyst along with the underlying bone spurs (osteophytes) at the DIP joint that are driving cyst formation. By addressing the root cause, this approach has the lowest recurrence rate. The procedure is outpatient, performed under local anesthesia. A skin flap may be needed to close the defect if the overlying skin is thin or damaged.

Recovery

• Days 10–14: Sutures removed

• Weeks 2–4: Return to normal activities

• Months 3–6: Nail deformity gradually improves as the nail grows out without the cyst pressing on it
  

Frequently Asked Questions

Will the nail groove go away after cyst removal?

In most cases, yes. Once the cyst is no longer pressing on the germinal matrix, the new nail that grows in will be smooth. It takes 3–6 months for the old grooved nail to grow out completely.

Is this related to my finger arthritis?

Yes. Mucous cysts are almost always associated with DIP joint osteoarthritis. The bone spurs create an opening in the joint capsule through which the cyst develops.

Mucous Cyst Care in Phoenix

If you have a bump near your fingernail that’s growing, causing nail changes, or concerning you, see a hand surgeon for proper evaluation. I treat mucous cysts for patients across Phoenix, Scottsdale, Mesa, Chandler, Gilbert, and the surrounding Valley communities. ☎ Schedule Your Consultation

Call (602) 258-4788 or visit toddrichardsmd.com to book an appointment with Dr. Todd Richards. Most insurance plans accepted. Same-week appointments often available.