What is TGCT?

Tenosynovial giant cell tumor (TGCT) is a type of typically benign tumor occurring in or around a joint. It can reduce movement in the affected joint and cause pain or stiffness.

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TGCT is classified into 2 types: localized and diffuse. A study in one country was used to provide estimates of how many people are diagnosed with TGCT worldwide each year. The estimates, by type, are 39 people per million for localized TGCT and 4 people per million for diffuse TGCT. However, it is unknown how many people are living with this rare disease.
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It is important to know which type of TGCT you have because it can make a difference in how it
affects you.
Click on a joint to learn more:
X DIFFUSE
  • Can spread throughout the entire joint.
  • Usually affects larger joints, like knees or hips
  • May be painful and can limit movement. Can be difficult to remove completely with surgery and often grows back. This may result in multiple surgeries that can cause scar tissue to build up or damage cartilage around the joint, leading to osteoarthritis.
  • May lead to the need for joint replacement surgery in severe cases.
 
 
X DIFFUSE
  • Can spread throughout the entire joint.
  • Usually affects larger joints, like knees or hips
  • May be painful and can limit movement. Can be difficult to remove completely with surgery and often grows back. This may result in multiple surgeries that can cause scar tissue to build up or damage cartilage around the joint, leading to osteoarthritis.
  • May lead to the need for joint replacement surgery in severe cases.
 
 
X DIFFUSE
  • Can spread throughout the entire joint.
  • Usually affects larger joints, like knees or hips
  • May be painful and can limit movement. Can be difficult to remove completely with surgery and often grows back. This may result in multiple surgeries that can cause scar tissue to build up or damage cartilage around the joint, leading to osteoarthritis.
  • May lead to the need for joint replacement surgery in severe cases.
 
 
X LOCALIZED
  • Is the more common form of TGCT.
  • Is limited (localized) to a specific portion of the joint.
  • Usually affects smaller joints, like those of the hands and feet.
  • May cause swelling and pain.
  • Usually can be removed with surgery, though tumors may grow back.
  • May require additional surgery to remove new growth.
 
 
X LOCALIZED
  • Is the more common form of TGCT.
  • Is limited (localized) to a specific portion of the joint.
  • Usually affects smaller joints, like those of the hands and feet.
  • May cause swelling and pain.
  • Usually can be removed with surgery, though tumors may grow back.
  • May require additional surgery to remove new growth.
 
 
X LOCALIZED
  • Is the more common form of TGCT.
  • Is limited (localized) to a specific portion of the joint.
  • Usually affects smaller joints, like those of the hands and feet.
  • May cause swelling and pain.
  • Usually can be removed with surgery, though tumors may grow back.
  • May require additional surgery to remove new growth.
 
 
X DIFFUSE
  • Can spread throughout the entire joint.
  • Usually affects larger joints, like knees or hips
  • May be painful and can limit movement. Can be difficult to remove completely with surgery and often grows back. This may result in multiple surgeries that can cause scar tissue to build up or damage cartilage around the joint, leading to osteoarthritis.
  • May lead to the need for joint replacement surgery in severe cases.
 
 
X LOCALIZED
  • Is the more common form of TGCT.
  • Is limited (localized) to a specific portion of the joint.
  • Usually affects smaller joints, like those of the hands and feet.
  • May cause swelling and pain.
  • Usually can be removed with surgery, though tumors may grow back.
  • May require additional surgery to remove new growth.
 
 
X DIFFUSE
  • Can spread throughout the entire joint.
  • Usually affects larger joints, like knees or hips
  • May be painful and can limit movement. Can be difficult to remove completely with surgery and often grows back. This may result in multiple surgeries that can cause scar tissue to build up or damage cartilage around the joint, leading to osteoarthritis.
  • May lead to the need for joint replacement surgery in severe cases.
 
 

The circles represent common locations of localized and diffuse TGCT. Larger circles indicate that more patients get TGCT in those particular joints. Typically, only one joint is affected at a time.

LOCALIZED TGCT
IS SOMETIMES CALLED:
  • Giant cell tumor of the tendon sheath (GCT-TS)
  • Nodular tenosynovitis
  • L-TGCT
Localized (GCT-TS)
80%-90%
OF TGCT CASES
DIFFUSE TGCT
IS SOMETIMES CALLED:
  • Pigmented villonodular synovitis (PVNS)
  • D-TGCT
Diffuse (PVNS)
10%-20%
OF TGCT CASES

What causes TGCT?

Scientists believe that TGCT tumors start with cells that line the joints. A small number of these cells can have a defect that causes them to make too much of a protein called colony-stimulating factor 1 (CSF-1).

Extra CSF-1 is thought to work 2 different ways. It acts like a magnet to attract inflammatory cells to the joint lining, which causes swelling. It also causes tumor cells to multiply.

TGCT developing in a knee

Learn more about TURALIO, the only FDA-approved oral treatment option for TGCT.

Learn more about the first and only treatment of its kind