Ganglion Cyst: a complete guide

Where does the jelly inside the cyst actually come from?

A ganglion is not a growth that appeared on its own.

It is an outpouching of a joint or a tendon sheath, and it is filled with the same raw material that lubricates them, concentrated and thickened. The fluid inside is mostly water and long sugar molecules, the ones that make joint fluid slippery. Sitting in a sac, the water is slowly squeezed out through the wall, and what stays behind gets thicker. That is why the jelly drawn out of a cyst looks like clear syrup rather than like the thin fluid inside a joint.

The sac itself is unusual. It has no true lining of the kind that glands and blood vessels have. Trace it back and you find a narrow stalk running from the sac down to the joint capsule or the tendon sheath it came from.

That stalk behaves like a one way valve. When you load the wrist, pressure inside the joint rises and a little fluid is pushed up the stalk into the sac. Getting back down again is harder. Fluid accumulates, the sac stretches, and the lump becomes obvious. Rest for a few days and some of it drains back or is absorbed, and the lump softens.

This explains almost everything patients notice. The lump grows during a week of heavy work or gardening and shrinks on holiday. It seems to appear overnight when in fact it has been filling for months.

Why does it come back after it has been drained?

Aspiration takes the jelly out through a needle.

It does not take out the sac, and it does not touch the stalk. The pump underneath is still running. So the sac, now empty and collapsed, is still connected to a joint that pushes fluid into it every time the wrist is loaded.

Sometimes that is enough. The collapsed walls can stick together, the stalk can scar shut, and the cyst never returns. Often it does not work out that way, and the lump refills over weeks to months.

Two practical points follow. First, aspiration is still a reasonable thing to do. It is quick, it can be done in the office, it settles the ache and the pressure, it confirms the diagnosis by showing the typical thick clear jelly, and some cysts do not come back. Being told the honest chance of return before the needle goes in is what makes it a fair choice rather than a disappointment.

Second, the same logic explains why surgery aims at the stalk rather than the lump. Removing the sac alone leaves the door open. Following the stalk down to its origin, and taking a small cuff of the joint capsule with it, is what makes return less likely. Even then, no operation removes the possibility completely, because the joint lining that produced the first cyst is still there.

Why is hitting it with a book such a bad idea?

The old remedy is to strike the cyst with something heavy, traditionally a Bible or a large dictionary.

A hard blow can burst the sac, the jelly spreads into the surrounding tissue, and the lump flattens. What has happened is that the contents were pushed out. The stalk is untouched, so the cyst commonly refills.

The problem is what else is under the blow. A dorsal wrist ganglion sits on top of the wrist bones and directly over the ligaments between them. Tendons that straighten the fingers and thumb run across the same area, and small sensory nerve branches run just under the skin. On the palm side, the radial artery is close by. A blow hard enough to burst a tough collagen sac is hard enough to bruise or tear those structures, and there are reports of broken bones from exactly this.

Bursting a lump at home also means nobody has looked at it. A flattened, bruised, partly emptied lump is harder to assess, not easier.

If a cyst is uncomfortable enough to make the book seem tempting, that is a good reason to have it looked at. There is an office procedure that does the same job deliberately, with a needle, under clean conditions, by someone who knows where the artery and the nerves run.

Why is a cyst on the palm side of the wrist a different conversation?

A cyst on the back of the wrist sits over ligament and bone.

A cyst on the palm side of the wrist, at the base of the thumb near the crease, sits next to the radial artery. That single fact changes the advice.

The radial artery is the one you feel when you take a pulse at the wrist. A volar ganglion often grows around it or is stuck to its wall, because the artery runs right past the joints these cysts come from. Putting a needle into a lump in that spot risks putting it into the artery, so aspiration there is usually avoided. The palmar cutaneous branch of the median nerve, a small nerve carrying feeling to part of the palm, crosses the same area and can be caught in scar.

If surgery is considered, the artery has to be dissected free of the cyst rather than simply cut around. Before that, the blood supply to the hand is checked, usually with a simple bedside test in which the two arteries at the wrist are pressed in turn and the hand is watched for color returning.

The result is that a volar wrist cyst gets a more cautious conversation than a dorsal one. Watching is weighted more heavily. Surgery is discussed as a slightly bigger undertaking, with the artery as the reason, and with the honest point that cysts in this position tend to return more often than those on the back of the wrist.

How do I choose between watching, draining, and surgery?

Start with what the cyst is doing to you, not with how it looks.

Ganglions do not turn into anything else and they do not spread. According to general guidance from the American Academy of Orthopaedic Surgeons, many need no treatment at all. Doing nothing is a real option, not a delay tactic, and a good number shrink or disappear over months.

Watching suits a cyst that is painless, does not restrict the wrist, and does not worry you once it has been assessed.

Aspiration suits a cyst that aches or presses, when you want the pressure gone soon and can accept that it may refill. It is quick, needs no time off, and can be repeated. It is not usually offered for volar wrist cysts, or for mucous cysts at the fingertip, where drainage carries a risk of carrying infection into the joint.

Surgery is considered when the cyst keeps coming back after aspiration, when it is large enough to limit movement, when it presses on a nerve and causes tingling or weakness, or when the diagnosis is uncertain and the tissue needs looking at. What you are trading is a lower chance of return against a scar, a few weeks of tenderness, some risk of stiffness, and a small risk to the nerves and vessels nearby.

Two things should not drive the decision on their own: the size of the lump, and the fear that it is cancer. A page cannot tell you what your lump is, and that is what an assessment is for.

What actually happens during a ganglion excision?

Removal is usually done as a day case.

Most dorsal cysts are removed through a short incision over the lump, sometimes placed along a skin crease so the scar settles well.

The sac is freed from the tendons and small nerve branches around it, which is slow work because those branches are fine and worth protecting. The stalk is then followed down to where it joins the joint. For the common dorsal cyst that origin is at the scapholunate ligament, the short band tying two wrist bones together. A small cuff of joint capsule is removed with the stalk, which is the step that lowers the chance of return, and the ligament itself is carefully left alone. The capsule is not closed tightly afterward, because a tight closure stiffens the wrist.

The arthroscopic version does the same job through small openings, using a camera inside the joint to find and remove the stalk from the inside. It leaves smaller scars and may be gentler on the tissue outside the joint. Whether it lowers the chance of return compared with open surgery is not settled, and both approaches are in normal use.

Risks are the ones you would expect around a joint that has to keep moving: a tender or thickened scar, some loss of the last few degrees of bending, numbness in a patch of skin from a small nerve branch, infection, and the cyst returning anyway. Serious problems are uncommon. Stiffness is the one most worth working to prevent.

What do the weeks after treatment actually feel like?

After aspiration there is little to describe.

The wrist is sore for a day or two, a small dressing comes off the next day, and the hand is used normally.

After open removal, the wrist is bandaged and often splinted for a few days for comfort. Fingers move from the start. The dressing comes down within about a week, and stitches commonly come out at ten to fourteen days. The main work of the first month is regaining wrist motion, because a wrist held still after surgery on the joint capsule stiffens quickly. Gentle bending and straightening several times a day is the treatment for that, and hand therapy is added when motion is slow to return.

Expect the area to feel tight, and expect the scar to be firm, raised, and sensitive for longer than you think reasonable. Scar tenderness commonly takes a couple of months to settle, and the skin over the back of the wrist is thin, so the scar can stay visible. Desk work is commonly resumed within a week or so and gripping work in two to four weeks, depending on the job and the hand.

Grip strength returns last, often over a couple of months. Aching in the wrist for a while after the cyst has gone is common and usually settles. These are ranges, not promises.

When is a lump on the hand not a ganglion cyst?

Most lumps in the hand and wrist are benign, and ganglions are the most common of all.

That is a reason to stay calm and still have the lump assessed, because a few behave differently and the treatment is not the same.

Some pointers separate them. A ganglion changes size, often over weeks. It is smooth, round, and usually movable, and it often glows when a small light is held against it, because light passes through fluid. A firm, rubbery lump on the palm side of a finger that does not change size at all may be a giant cell tumor of the tendon sheath, which is benign but tends to return after removal.

The features that prompt a closer look are steady growth over weeks, a hard lump fixed to the tissue underneath, pain at night, a lump that does not transilluminate, changes in the overlying skin, or numbness and weakness in the hand. Cancer in the hand is uncommon, but uncommon is not never, which is why a lump is assessed rather than guessed at. The hand and wrist lumps page sets out the range.

One more variety belongs here. A small cyst at the end joint of a finger, beside the nail, is a mucous cyst, and it grows out of an arthritic joint rather than a normal one. Treating it means treating the arthritis and the bone spur underneath, not just the bump.