Lumps and Bumps of the Upper Extremity
⌚️ read time: 5 minutes
If you’ve ever woken up to find a large soft bump on the back of your wrist, chances are you’ve had a ganglion cyst.
While most common on the back of the wrist, these occur with striking frequency throughout the wrist, hand, and fingers. So whether you’ve already experienced one of these cysts, or you’re unwittingly in line to get one in the future, let’s do a quick tour of all you need to know about ganglions.
Ganglion cysts are usually painless - but not always
A ganglion cyst, in its most basic form, is a fluid-filled cyst that comes from a joint (see drawings below). They can occur anywhere in the body but they are extremely common in the wrist and hand.
It is still a little bit unclear why each cyst develops. We think they may occur from a small injury, a genetic predisposition, or some accumulation of injury over time.
By the way, these are ridiculously common. I bet I see 3-4 each day in my clinic!
Either way, a small pouch of fluid pushes its way out of the joint (figure below). Over time, the joint will continue to generate more and more fluid, and the cyst will grow and grow. If this goes on long enough, the cyst can get large enough to push all the way up to your skin — and that’s typically when you notice it.
Now you essentially have a water balloon in your hand or wrist that is anchored at the joint. A small one-way valve develops at the entrance to the cyst that allows joint fluid (into the cyst), but not out (back into the joint).
Remember this valve for later when we talk treatment options.
The good news?
Ganglion cysts are usually painless — and certainly not dangerous. They do not cause long-term damage. It is not a cancer and will not spread.
However, if they are in just the wrong spot, they can cause discomfort or limitations as they get pinched or rub against nearby structures.
We gather clues for a diagnosis, but there is always some uncertainty
With any mass or growth in the body, it is important to remember the only way to truly know what it is (ie, diagnosis) is to remove it surgically and have a pathologist look at it under the microscope.
Anything short of that is just collecting clues to guess the most likely diagnosis.
In the case of a ganglion cyst, we rely on five main clues.
Location
Ganglions are most common over the back of the wrist and, somewhat less commonly, on the palm side of the wrist. They also often happen around the knuckles of the fingers.
Growth
It is common for ganglions to randomly grow and shrink day to day or week to week. This particular detail is a classic finding in a ganglion cyst that does not occur in other masses.
Appearance
If they are very large, we can do something called transillumination. I literally shine my phone light through the mass. If it appears to transmit the light and glow, that indicates a likely ganglion cyst.
Feel
The larger ganglion cysts have a classic feel to them. They are soft and somewhat ‘bouncy’ when you push on them. They oftentimes will easily slide around a bit. Basically like a water balloon.
MRI
If the diagnosis is unclear, we may get an MRI. This gives us clues as to how the growth looks and where it is coming from. But again, even an MRI does not confirm the diagnosis. This is why, for most of these cysts, an MRI is not worth it.
Your chosen treatment must align with your goals and symptoms
Always keep this in mind. Because these cysts are not dangerous, you really do not have to do anything. Remember this when choosing your treatment!
If the cyst does not bother you that much, then don’t have surgery!
If your cyst is very painful, please realize that is outside the normal bounds for this type of cyst.
It may be that it is in just the wrong spot, causing you notable pain. But remember it could also be that something else is going on with your wrist (tendinitis, sprain, you name it) that is causing wrist pain — and the cyst is just a coincidence.
Alternatively, your growth may not be a ganglion cyst at all but instead is a different type of painful mass altogether.
I can drain these cysts - but I typically don’t recommend it
Most patients who see me for this cyst will naturally assume that I can or will drain it. While this is technically true, I’m rarely recommending this as a course of treatment these days.
Our best available studies show that draining a ganglion cyst is highly unlikely to be successful. This has been shown to work in only 20-30% of cysts!
And this of course makes sense when you remember the anatomy. The problem that created the cyst is the little valve at the joint allowing fluid into the ‘balloon.’ If all we are doing is using a needle to ‘pop’ the balloon and drain out the fluid, as soon as that small needle hole heals over, the balloon will just re-fill with more fluid.
Moreover, joint fluid is thick and requires a large needle to drain. Which means that drainage is not comfortable and does carry a small risk of infection.
Can you see why I don’t routinely recommend it?
The pros/cons just don’t add up.
PS - Many of my patients know the old folk medicine trick of ‘smashing ganglion cysts with a Bible.’ Presumably, this is how these cysts were treated in medieval times when the Bible just happened to be the heaviest, flattest thing around with which to smash!
To be clear, this is a highly ineffective method of treatment that has a recurrence rate as poor as needle drainage.
Surgery is your surest bet. But cysts can still come back.
If you grow tired of the cyst or it bothers you too much, surgery is your most reliable option. However, it is crucial to understand that even with perfect surgery, about 5 to 10% of ganglion cysts can still come back after surgery.
Remember, ganglions are extremely common at baseline, and while surgery treats the cause of one cyst, the factors that came together to cause it in the first place can easily recur.
In surgery, I will move the cyst out of the way and work my way all the way down to the joint level. There is usually a small stalk (where the valve is) through which the cyst is exiting from the joint (see drawings above). This stalk needs to be excised in its entirety in order to best prevent cyst recurrence.
After a few stitches and a few weeks of healing, you should be right back at it!
Takeaways:
Ganglion cysts are very common growths seen in the hands and wrists
While a diagnosis cannot technically be made without surgically removing the cyst, there are lots of clues that make us nearly 100% confident in a diagnosis without surgery
These cysts are not dangerous - it is perfectly reasonable to just live with them
Cyst drainage can be painful and only works 20-30% of the time. Surgery is successful in preventing regrowth of the cyst in 90-95% of cases.
Whether you’ve had one of these cysts in the past, or you’ve seen them in relatives or friends, I hope you now have a better understanding of these extremely common lumps.
If there’s anything about these cysts you’d like to learn more about, please reach out at rulesofthumb@nickgolinvauxmd.com!
