​That bump on your wrist could be a ganglion cyst

A ganglion cyst on a wrist

What is that annoying and sometimes painful lump on your wrist? It’s more than likely a ganglion cyst.

Here is some good news: They’re typically harmless. The soft sacs of fluid often show up on the top or bottom side of the wrist closest to the thumb. Typically the cyst is about the size and shape of a pea – however, they can sometimes become larger. And they’re usually only visible when the wrist is bent.

So where do ganglion cysts come from? How common are they? And why do they sometimes impede your workout? We spoke to Jennifer Moriatis Wolf, MD, professor of orthopaedic surgery, who specializes in hand surgery, at the University of Chicago Medicine, about the condition.

The cause of ganglion cysts

Although the answer is widely debated, Wolf has her own theory on their origin.

“My thought is that it’s microtrauma or a minor trauma that causes a small either hole or damage to the ligament,” said Wolf. “The damage is enough for fluid to escape from the wrist like a spout. Then the body walls that off and creates a cyst.”

The cysts can appear in children and adults. In fact, these cysts are so common that Wolf treats them about five times a week. Typically, pain or concern is what drives a patient to the doctor.

“People want to know - is it going to go away? Is it not going to go away?” she said. “The common teaching is in adults these don’t tend to go away all that often.”

The pain someone feels is due to the cyst pressing against the nerves in the wrist. On the top of the wrist, the ganglion attaches to the scapholunate ligament, which connects the two wrist bones that are on the thumb side of the wrist. If the cyst is on the bottom side of the wrist, it can push into the radial artery, which is a major artery in the forearm.

In adults, it is common for the cyst to go up and down in size, which can create the illusion that it is gone. When the cyst is enlarged, it can be troublesome to bend or straighten the wrist.

“I have a lot of military people who come in and can’t do pushups because bending their wrist is very painful,” said Wolf. “This can obviously have a huge effect on their training.”

Diagram of a ganglion cyst

Treatment options

There are various ways to treat a ganglion cyst. To help with pain a patient can wear a splint at night. To get rid of the cyst a physician can drain it with a needle; unfortunately there is a 50 percent chance of the cyst returning with this treatment method.

“I think that happens because it’s sort of like putting a needle into a balloon that is attached to a helium tank,” said Wolf. “The helium is going to keep pumping on in. You can suck it out once, but it is going to come right back up.”

Another option is surgery. In that case, a surgeon will extract the ganglion cyst from its base and completely take it out of the wrist. The risk of extracting a ganglion from the top of the wrist is minimal. But trying to remove it from the bottom of the wrist can be a more complex procedure because of the nearby radial artery.

“Luckily, if the radial artery is stuck to the cyst and gets damaged, it can be repaired,” said Wolf. “The surgeon needs to have some comfort in dissecting around or next to major arteries in the hand.”

Is it benign or malignant?

Most people who come to the doctor about a ganglion cyst are worried whether it’s cancerous. But, according to Wolf, that’s very uncommon. However, this can’t be 100% certain unless pathology is performed at surgery.

To be more certain that the mass is a cyst, physicians can use several diagnostic techniques. The easiest option is transillumination, which is when light is shined on a part of the body to detect any abnormalities. If the light passes through, the bump is much more likely to contain fluid, and to be a cyst.

For arguments sake, if the cyst is on the thumb side of the wrist, rounded, and your finger can bounce off it, you should be in the clear.

Jennifer Moriatis Wolf, MD

Jennifer Moriatis Wolf, MD

Jennifer Moriatis Wolf, MD, is a renowned hand surgeon with expertise in the surgical and non-surgical treatment of bone, nerve, tendon and ligament injuries caused by trauma or overuse.

Learn more about Dr. Wolf