Giant Cell Tumor

What is a giant cell tumor?

A giant cell tumor (GCT) is a noncancerous (benign) tumor that usually forms at the end of your long bones. Also called osteoclastomas, these rare bone tumors are most common in people ages 20 to 40 years old. They usually form at the bottom of your thigh (femur) or the top of your shin (tibia), near your knee. Less often, they form near your hip, shoulder, wrist or tailbone.

Giant cell tumors are rare overall, affecting only 1.7 per 1 million people. Still, GCTs account for 15% to 21% of all benign tumors that start in your bones.

GCTs that grow in soft tissues around joints (instead of bone) are called tenosynovial giant cell tumors.

Although giant cell tumors aren’t cancerous, they can grow fast and damage surrounding tissues. Often, they recur (come back) after treatment. This is why you should see a healthcare provider at the first sign of a giant cell tumor.

What are the symptoms of a giant cell tumor?

Pain is the most common sign of a giant cell tumor in your bone. The pain may be mild at first, but it usually worsens as the tumor grows. You may also have:

• A noticeable bump or lump
• Limited movement at the joint near the tumor
• Joint pain, especially with movement
• Swelling
• Fractures, as the GCT weakens the bone around it

What causes a giant cell tumor?

Medical researchers don’t know what causes giant cell tumors. But they’ve found common gene changes (mutations) in some people with this condition. It’s likely not inherited or related to your environment or habits.

Risk factors

If you have a condition called hyperparathyroidism, you may be more likely to get many GCTs throughout your body. In rare cases, giant cell tumors form in people who have Paget’s disease of the bone.

What are the complications of this condition?

Although they’re benign, in rare instances, giant cell tumors can spread to your lungs. Unlike cancers that spread, giant cell tumors aren’t usually fatal.

Even more unusual, giant cell tumors can sometimes become malignant (cancer). This happens with only 4% of giant cell tumors. Your healthcare provider will monitor your condition to catch any changes in the tumor that may pose risks to your health.

How is a giant cell tumor diagnosed?

A healthcare provider will do a biopsy to diagnose a GCT. They’ll take a small tissue sample from the tumor that a pathologist will examine under a microscope for signs of a GCT. The pathologist will look for the “giant cells” that give the condition its name.

Your provider may also do imaging tests to see the tumor inside your body, including:

• X-rays
• CT scan
• MRI
• Bone scans
• PET scans

How is a giant cell tumor of bone treated?

Usually, healthcare providers treat giant cell tumors with surgery. A healthcare provider scrapes the tumor away from your bone (curettage). Then, they fill the bone with a bone graft to strengthen it. With large tumors, your healthcare provider may have to remove the entire bone segment. Afterward, they may reconstruct it with a prosthesis.

If your healthcare provider can’t safely remove the entire tumor with surgery, you may have nonsurgical treatments, such as:

• Denosumab (Xgeva^®). This medicine is a monoclonal antibody that shrinks tumors and strengthens the surrounding bone.
• Embolization. This procedure blocks the blood vessels that send blood to the tumor so the tumor starts to die.
• Ablation therapy. This procedure uses microwave energy to destroy the tumor.
• Radiation therapy. This treatment uses high-powered X-rays to shrink the tumor and kill the cancer cells.

How soon after treatment will I feel better?

Your recovery time depends on your treatment. Following surgery, you may need to wear bandages for several weeks while the wound heals. In the meantime, you may need to use crutches. If you need a prosthetic device, recovery will likely involve working with a physical therapist to help you get used to it.

Your healthcare provider will describe your recovery timeline and answer any questions you may have about how you should prepare.

How can I prevent a giant cell tumor?

Experts don’t know what causes giant cell tumors, so there’s no way to prevent them. Still, you can improve your outlook by seeking care early on. If you notice pain, swelling or a lump around one of your bones or joints, see a healthcare provider immediately. GCTs are often easier to treat when they’re found early.

What is the outlook for giant cell tumors?

Giant cell tumors are rarely life-threatening. But they can damage your bones and tissues. If you have any signs of a giant cell tumor, it’s important to see a healthcare provider right away. It’s a good idea to see an orthopaedic oncologist, who specializes in bone cancer.

Working with a specialist who removes all signs of the tumor reduces the chances that it will grow back.

What can I expect if I have a giant cell tumor of bone?

After treatment, you’ll have regular follow-up appointments with your healthcare provider to check for signs that the GCT has grown back. These tumors often return after treatment. Most GCTs that come back do so within the first two to five years after surgery. Still, you may need life-long follow-up appointments.

Ask your healthcare provider how often you’ll need check-ups.

When should I see my healthcare provider?

Contact your healthcare provider if you’re noticing signs that a giant cell tumor has returned. Look for symptoms like new bone or joint pain and swelling. Your healthcare provider will monitor you for new tumors, but you should still reach out if you notice changes in between appointments.

What questions should I ask my healthcare provider?

You might want to ask your healthcare provider:

• How aggressive (fast-growing) is the tumor?
• What are my treatment options?
• What are the benefits and risks associated with treatment?
• What are the chances that the giant cell tumor will come back after treatment?
• How often will I need follow-up appointments?