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A mucous cyst is a type of ganglion, a small, harmless sac filled with a clear, sticky fluid. The fluid is a mix of chemicals normally found in the body. A mucous cyst is a ganglion of the DIP joint. The cyst is attached to the joint by a stalk of tissue. Typically only one cyst appears, though an occult (concealed) cyst may also be found closer to the joint. They are associated with osteoarthritis(OA) and usually develop in patients 50 to 70 years old. These cysts appear between the last joint of the finger and the bottom of the fingernail. Unless a mucous cyst is painful or in danger of rupturing it can be left alone without causing harm to the patient. But even surgically removing a mucous cyst may not alleviate pain if the underlying cause of the pain is OA.

Mucous cysts are typically found in patients with OA. Doctors do not know why mucous cysts develop. Doctors also don't understand exactly how these cysts form. One theory suggests that mucous cysts are formed when connective tissue degenerates (wears away). Collagen is a protein found in connective tissue. The leftover collagen is thought to collect in pools, and the pools form cysts. Fluid seems to move from the joint into the cyst, but not the other way.

What Can You Do?
Observation is often sufficient treatment for mucous cysts. Mucous cysts are not typically harmful and usually do not grow worse without treatment.

What Can a Doctor Do?
Surgery is recommended if you feel significant pain or if the cyst and skin appear ready to rupture.
Needle puncture is one option. In this procedure, the cyst is punctured and aspirated. (Aspiration means drawing the fluid out with suction.) However, this procedure has less than a 50 percent success rate.

Another option involves excision (removal) of the cyst and its connection to the DIP joint. Patients should be aware that removing a mucous cyst may not eliminate pain if the pain is from the underlying OA.In this procedure, the cyst, stalk, and any bone spurs on the DIP joint are removed. If the skin on the finger is too closely attached to the cyst, a bit of the skin may need to be removed from the finger. If that's the case, a small skin graft is added to the spot.
Surgery can usually be performed using regional anesthesia, meaning only the arm or finger is numbed with lidocaine. Dr. Kilaru will discuss your options with you.

How Successful it Treatment?
If you have surgery to remove a mucous cyst and a skin graft is used, you will wear a cast or splint for two weeks. Otherwise, the fingers can be moved sooner. You will be shown specific exercises to help you regain full motion in the finger. Exercises should be continued until you can move the finger normally without pain.

What Happens if You Don't Have Treatment?
Your doctor may simply have you observe for any changes in the cyst. During this period of observation, let your doctor know of any significant increases or decreases in the size of the cyst.