What is a Mucous Cyst?

A mucous cyst is a fluid filled sac that can presents on the back of the finger joints, it most commonly occurs at the distal most joint, the DIP joint, close to the nail. It usually occurs in patients over the age of 50, more commonly in women, and is associated with arthritis of the finger joints. It can also cause deformity of the nail due to direct pressure on the growing portion of the nail, which is very close to the DIP Joint

Its correct name is in fact a digital ganglion, but it is commonly referred to as a mucous cyst, even though it doesn’t contain mucus!

How is it treated?

Minor, small lesions that do not cause any symptoms are usually left alone, as they can regress and disappear. Larger cysts are usually removed with a minor operation. This can be done under local anaesthetic. There is usually a small bony outgrowth (osteophyte) under the cyst, which also requires removal.

Occasionally the skin is very fragile and thinned due to the cyst, and a small rotational skin flap is required to cover the area after excision. This adds a little more time to the surgery, but can still be performed under local anaesthetic.

Puncture of the cyst with a needle is discouraged, as this can cause infection, which if it extends into the finger joint, can be serious.

What are the complications?

The surgery is extremely safe and the success rate is over 90%. The complications are rare but include stiffness, infection, an abnormal pain response, and recurrence of the cyst. Frequently recurrent cysts occasionally occur, and sometimes the best way of fully treating these is to remove the cyst and fuse the joint.

What is the recovery period?

The operation requires the finger to be rested in a dressing for several days. Sutures are removed at 10-14 days. Most patients are back to full activity by 3 to 4 weeks.