What is Tenosynovial Giant Cell Tumor?
Tenosynovial giant cell tumors are rare benign tumors that form in the joint. They involve the synovium, bursae, and tendon sheath. As these are benign they do not spread to other areas of the body.
Synovium is a thin tissue or membrane in the inner surface of the joints, bursae, and tendon sheath.
Bursae are small fluid-filled sacs or cushions around the bones, tendons, and muscles around the joints.
Tendon sheath is a layer that covers the tendons (fibrous tissue that connects the muscles to the bones).
Due to the tumor, the synovium, bursae, and tendon sheaths thicken and overgrow.
Types of Tenosynovial Giant Cell Tumor
Depending on the location and speed of growth these tumors are divided into two types:
The localized giant cell tumor is the one that grows slowly. It starts from the smaller joints such as those of hands. They are known as giant cell tumors of the tendon sheath.
Diffuse giant cell tumor affects the larger joints such as those of knee, hips, shoulder, ankle, and elbow. They are known as pigmented villonodular synovitis.
Both types of tenosynovial giant cell tumors are found inside the joints. Diffuse giant cell tumors can also be found outside the joint and in rare cases can spread to lymph nodes or lungs.
What Are The Causes Of Tenosynovial Giant Cell Tumor
Tenosynovial giant cell tumors can occur due to change in a chromosome known as translocation. During the process, the pieces of chromosomes break and change places. Now, what causes this translocation is not known.
A chromosome contains genetic code for producing proteins and due to translocation, an excess of protein known as colony-stimulating factor 1 (CSF 1) is produced.CSF1 attracts the cells that have its receptors which include the white blood cells called macrophages. These cells lump together and eventually form a tumor.
Tenosynovial giant cell tumors are common in people of 30 and 40 years of age. The diffuse type is more common in men. These are rare tumors and only 11 out of 1 million people in the USA are diagnosed with it every year.(1)
Signs and Symptoms of Tenosynovial Giant Cell Tumor
Depending on the location and severity, the signs and symptoms of tenosynovial giant cell tumors may vary.
There is swelling on the affected joint or a lump is felt at the joint. There is stiffness and the patient finds the movement of the joint difficult.
There is pain and tenderness and warmth of the skin over the joint. Pain and swelling is sometimes the first symptom to be seen.
A locking and popping sound is felt when the joint is moved.
Sometimes the symptoms of tenosynovial giant cell tumors can cause arthritis damage and degeneration of the joint and the surrounding cartilage and bone.
If not treated, tenosynovial giant cell tumors can further lead to chronic debilitating disease and significant functional impairment of the affected joint.
Diagnosis of Tenosynovial Giant Cell Tumor
The diagnosis of the tumor is made is based on the identification of the characteristic symptoms and detailed patient history. A few tests are performed to confirm the diagnosis of tenosynovial giant cell tumors and that includes:
- X-ray: Helps rule out other conditions and also shows degeneration of the surrounding bone and cartilage.
- Biopsy of the tissue from the joint: It allows the doctor to view what kind of cells make up tumors.
- Magnetic resonance imaging (MRI): It can be very effective in diagnosing the tumor.
- Synovial fluid sample: If this fluid is bloody there would be a need for further testing.
Treatment of Tenosynovial Giant Cell Tumor
Surgery is the main treatment of tenosynovial giant cell tumor. The surgery tends to be successful and has a good prognosis but there is a risk of recurrence.
The chances of recurrence of diffuse-type of giant cell tumors are more. In such cases, multiple surgeries are required. People in case of recurrence are advised drugs that are known as colony-stimulating factor 1 receptor inhibitors that can block the CSF1 receptor to stop the tumor cells from collecting.
Radiation therapy can be given after surgery to remove the parts of tumors that weren’t removable in the surgery. The radiation machine can be used straight on the affected joint.
Tenosynovial giant cell tumor is not usually cancerous but can lead to permanent joint damage and disability. Therefore if any symptom of this condition if noticed, a doctor should be consulted and treatment should be started as soon as possible.