What is a giant cell tumor?
A giant cell tumor is a benign solitary tumor that usually grows in the ends of long bones, and contains unusually large cells that are called giant cells. They most commonly occur in the femur (thighbone), tibia (shinbone), and distal radius (wrist), and sometimes occurs in the lower end of the spinal cord.
A giant cell tumor can be quite destructive locally, and has potential to break through the bone's outer layer (cortex), cause a fracture, known as a pathological fracture, and extend into the surrounding soft tissues.
A giant cell tumor is considered benign, yet giant cell tumors can spread to the lungs. Don't worry too much, though — this rarely happens.
When it does occur, the prognosis for your child is still good; occasionally the tumor regresses without intervention.
How we care for giant cell tumors
Working together with clinicians and researchers at the Dana-Farber Cancer Institute and Harvard Medical School, the Head, Neck, and Skull Base Surgery Program is dedicated to advancing the understanding, diagnosis, treatment, cure, and prevention of giant cell tumors and related conditions.
Giant Cell Tumor | Symptoms & Causes
What causes a giant cell tumor, and whom does it affect?
We don't fully know. Scientists do know that giant cells form when there is a proliferation of mononuclear cells that fuse together. It is unusual for this to happen in children prior before the growth of bones reaches full potential, although it occasionally does.
Giant cell tumor usually occurs in adults who are between the ages of 20 and 40. It seems to affect more women than men.
What are the symptoms of a giant cell tumor?
Symptoms vary, but here's a list of the most common ones:
- decreased joint range of motion
- a tender hard mass may be felt
- muscle atrophy
- elevated temperature of the overlying skin
The symptoms of a giant cell tumor may resemble other medical conditions or problems. Always talk to your doctor for a diagnosis.
Giant Cell Tumor | Diagnosis & Treatments
How is a giant cell tumor diagnosed?
In addition to a taking a complete medical history and performing a full physical examination, your child's doctor may use one or more of the following tests to diagnose giant cell tumor:
- X-ray: X-rays are very useful in the diagnosis of bone tumors. They are the first diagnostic study, and they often give your doctor information regarding the need for further testing.
- Magnetic resonance imaging (MRI):This test outlines the extent of the tumor within the bone and joint and the relationship of the tumor to the muscles, nerves, and blood vessels.
- Computerized tomography scan (also called a CT or CAT scan): A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays. It is used primarily to assess the chest and lung for metastatic (spreading) tumors.
- Bone scans: A nuclear imaging method used to detect bone and metastatic tumors. Bone scans can determine if there are abnormalities in other bones. This test does not distinguish between tumor, infection, or fractures.
- Complete blood count (CBC): A measurement of size, number, and maturity of different blood cells in a specific volume of blood.
How is a giant cell tumor treated?
Treatment of a giant cell tumor may involve one or a combination of the following surgical procedures performed by a pediatric orthopedic surgeon:
- Curettage: This is the most common form of treating a giant cell tumor. Curettage is an operation during which the tumor is scraped out of the bone. For this procedure, surgeons make an incision in the bone to create a window to expose the entire tumor. The tumor is then completely removed.
- Cryotherapy: This may be used to supplement curettage. Surgeons fill the cavity that remains after curettage with liquid nitrogen to freeze the area. It's then thawed out and may be frozen again. The freeze and thaw cycle, which would help prevent any missed remnants of the tumor from growing, is repeated once or twice.
- Bone grafting or cement packing: Sometimes the remaining cavity is packed with donor bone tissue (allograft), bone chips taken from another bone (autograft), or other materials, including bone cement (the same material used in total joint replacements), depending on the preference of the surgeon.
- En bloc resection: For more aggressive tumors, the operation will likely involve en bloc resection, which is the surgical removal of bone containing the tumor, rather than curettage.
- Internal fixation, with pins, may be required to restore the structural integrity of the bone.
If significant bone loss results, allograft transplants or metallic replacements are used to reconstruct the bone. Although common in the past, this aggressive procedure is not commonly used as the initial treatment today.
What's my child's long-term outlook?
Generally speaking, these tumors can be treated successfully and the long-term prognosis is good. These tumors can, however, recur. Prompt medical attention and aggressive therapy are important for the best prognosis.
Continual follow-up care is essential for a child diagnosed with a giant cell tumor. It's rare to see the tumors spread to the lung, but your child will be monitored periodically with chest x-rays and sometimes CT scans to look for the occurrence of lung lesions.