A ganglion cyst is a common, non-cancerous lump that forms near a joint or tendon sheath. This fluid-filled sac arises most frequently around the wrist or hand, though it can appear on the foot or ankle. The sac contains a thick, clear, jelly-like substance similar to the fluid that lubricates your joints. When a cyst becomes symptomatic, draining the fluid (aspiration) is a common, minimally invasive first treatment option. While aspiration reduces the cyst’s size immediately, it is not always a permanent solution.
Identifying the Cyst
Ganglion cysts most often appear as a noticeable, smooth bump just under the skin. They are typically found on the back (dorsal) or palm side (volar) of the wrist, but they can also develop near joints in the fingers or on the top of the foot. The exact cause is not fully understood, but they are believed to form when the lining of a joint or tendon sheath bulges out. This protrusion allows synovial fluid, which lubricates the joint, to collect outside of its proper space.
A healthcare provider usually diagnoses a ganglion cyst through a physical examination. The lump may feel firm or spongy, and its size can fluctuate with activity. A classic diagnostic method involves transillumination, where light passes through the fluid, confirming it is a fluid-filled sac rather than a solid tumor. If the diagnosis is unclear or the cyst is located near a major artery, an ultrasound or magnetic resonance imaging (MRI) scan may be used to confirm its nature and map surrounding structures.
Aspiration: The Draining Procedure
Aspiration is an outpatient procedure performed to drain the fluid from the cyst. The area is first cleaned and then numbed with a local anesthetic injection. The provider inserts a sterile needle into the cyst to withdraw the thick, viscous, mucin-rich fluid. Because the fluid is dense and jelly-like, aspiration can sometimes be challenging, potentially requiring a larger gauge needle.
After the fluid is drained, some practitioners may inject a corticosteroid solution into the cyst sac. This is done to reduce inflammation and scar tissue formation, although the benefit of adding a steroid is debated among specialists. The immediate success rate for reducing cyst size is high, but the procedure carries minor risks, including localized bruising, mild pain, or infection. When the cyst is located on the volar side of the wrist, ultrasound guidance may be used to ensure the needle avoids nearby structures, such as the radial artery.
Recurrence and Conservative Management
The primary limitation of aspiration is the high rate of recurrence, which can range from 40% to over 70%. The cyst often returns because aspiration only removes the fluid, leaving the small connection, or “stalk,” linking the cyst to the joint capsule or tendon sheath intact. Fluid continues to leak through this one-way valve, causing the sac to refill over time. Recurrence typically happens within a year of the initial procedure.
Because these cysts are benign and often painless, simple observation, or “watchful waiting,” is a common initial strategy. Up to 58% of ganglion cysts may resolve spontaneously without intervention over months or years. If the cyst causes discomfort during activity, conservative measures like immobilization with a wrist brace or splint can be used. Reducing movement can decrease fluid accumulation, causing the cyst to shrink and alleviating symptoms.
When Surgery is Necessary
If a ganglion cyst causes persistent pain, limits joint function, compresses a nearby nerve causing tingling or numbness, or recurs repeatedly after aspiration, surgical excision may be recommended. This definitive procedure is called a ganglionectomy. The goal is to remove both the visible cyst sac and the deep-seated stalk (pedicle) that connects the cyst to the joint capsule.
Removing this connection point is the most important step for preventing recurrence. The procedure is typically performed on an outpatient basis, and recovery usually involves controlled movement or splinting for two to six weeks. Recurrence rates following surgical excision are significantly lower than with aspiration, generally falling in the range of 5% to 20%. While surgery has a higher success rate, it carries risks associated with any operation, such as scarring, stiffness, or injury to surrounding nerves and blood vessels.