What Are Retinacular Cysts?
Retinacular cysts are a type of small ganglion cyst found on the palm or base of the finger. The lumps develop along the tendons or joints of the wrists or hands. These noncancerous lumps are typically the size of a pea. Larger cysts can be around an inch (2.5 centimeters) in diameter. The size of a cyst can fluctuate, increasing in size when the joint is used for repetitive motions.
They can be associated with an underlying tendonitis or trigger finger. These cysts are typically painless, but can cause pain, tingling, numbness or muscle weakness if they press on a nerve. In some cases the location of the cyst may also interfere with joint movement.
Causes & Risk Factors
It is unclear what causes ganglion cysts to develop. The cyst grows out of a joint or the lining of a tendon, looking like a small bubble on a stem. They tend to occur when the tissue surrounding a tendon or joint bulges out of place. The cyst is filled with fluid similar to that in joints and around tendons.
Increased ganglion cysts risk factors include:
- Osteoarthritis - Joints closest to the fingernails, affected by osteoarthritis are at a higher risk of developing ganglion cysts near those joints.
- Age & sex - Ganglion cysts most commonly occur in women between the ages of 20 and 40, but can develop in anyone.
- Tendon & joint injuries - Tendons or joints that have sustained injury in the past are are risk of developing ganglion cysts.
Treatment Options
As retinacular cysts are benign, observation is warranted if non-painful. Painful cysts may be drained (aspiration) in the office using a small needle and local anesthetic.
Cysts that do not resolve with aspiration or that recur may be surgically removed. Surgical cyst removal is typically a quick outpatient procedure. The cyst and small square of underlying tendon sheath are removed. This can be done under local anesthetic or a light sedation. Light activity is recommended until the sutures are removed around one week. Recurrence after surgical excision is rare.