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tgct awareness

FREQUENTLY ASKED QUESTIONS

About TGCT

TGCT stands for tenosynovial giant cell tumor. It is a rare, non-malignant tumor affecting joints and sometimes the surrounding area.1 Non⁠-⁠malignant means it is not cancerous. It is a type of tumor that usually grows slowly and doesn’t spread to other parts of the body.1–⁠3

TGCT can cause pain, swelling and limited movement in the affected joint. If left untreated, it can cause permanent damage.1,4 Approximately 1 in 23,000 people in Europe will be diagnosed with TGCT every year.5,6

TGCT is sometimes called by other names, such as pigmented villonodular synovitis (PVNS) or giant cell tumor of tendon sheath (GCTTS).1

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The most common place for TGCT to develop is in the knee, however tumors can occur in other joints depending on what type of TGCT it is.7

There are two types of TGCT: diffuse-type (D-TGCT) and nodular-type (N-TGCT). Nodular TGCT is the most common type. Nodular tumors are often found in smaller joints like fingers or wrists, and they don’t usually cause a lot of pain or joint dysfunction.8

Diffuse TGCT, on the other hand, is less common. These tumors are often found in large joints, like hips or ankles. Diffuse tumors can extend beyond the joint, with a greater risk of causing damage to nearby bones, cartilage and tendons in some cases.8

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TGCT develops when some of the cells in our joints change due to a genetic mutation. The mutation causes these cells to produce too much of a protein called colony stimulating factor-1 (CSF1).9

Over time, this protein causes a build-up of inflammatory cells (usually involved in the immune reponse) within the affected joint. This can cause swelling and eventually lead to tumor formation.9

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Diagnosis and treatment of TGCT

TGCT is diagnosed in three key steps:

  • Clinical assessment: You and your doctor will have a conversation about the symptoms you are experiencing to understand if this might be TGCT. The symptoms of TGCT can look like other conditions, which is why you need the next step to double check – imaging1,7
  • Imaging: An MRI (a type of scan in the hospital) will be used to look at the tumor inside your body (using a special fluid called contrast), to see if it looks like TGCT and what type it might be.1 However, a third and final step is needed to finally confirm if it is TGCT
  • Biopsy: A biopsy involves taking a sample of tissue from the tumor so it can be examined in a lab by experts. If surgery is already planned, a sample of tissue can be taken at the same time to send for testing in the lab. Otherwise, the biopsy will occur in a separate procedure1,10,11
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The standard treatment for TGCT is surgery. The aim of surgery is to remove as much of the tumor as possible to reduce the risk of it coming back.1,8

However, some people might not be able to have surgery for various reasons, for example, where the tumor is located might make it difficult to remove. Ongoing research continues to look at different options for people with TGCT who cannot have surgery.1

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While surgery aims to remove as much of the tumor as possible, there is still a risk it can come back (known as recurrence).8 Diffuse TGCT typically has a higher risk of recurrence (72% chance it might come back)7 vs nodular type (up to 15% chance).12–14

Unlike nodular TGCT, which is generally contained within the joint, diffuse tumors can sometimes grow in and around the joint. Due to this growth pattern, it can make it tricky to remove all of the tumor. Incomplete removal of the tumor can result in recurrence.8

People with diffuse TGCT may need repeated surgeries to try and remove the tumor completely.7 However, repeated surgeries can cause further joint issues.15

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Living with TGCT

Certain foods or dietary changes can help reduce inflammation, which might be beneficial for conditions like TGCT which cause inflammation in the affected areas.16 Currently however, there is no published research to support the benefit of specific changes to diet for TGCT.17

In terms of treating joint pain and swelling, there may be a few things to try, such as placing an ice pack on the joint area or taking pain killers (with advice from your doctor or nurse).18

The information provided here is intended to support your understanding of managing TGCT and should not replace professional medical advice. Always consult your healthcare provider with any questions you may have regarding a medical condition.

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It can be difficult to stay physically active if you have TGCT,7,11 particularly if the tumor is in your knee, hip or ankle. However, regular physical exercise is still important to maintain a healthy lifestyle.19

Certain types of exercise can help to restore strength and range of motion in joints, including after surgery.20 You might work with a physiotherapist who will create a physical exercise plan tailored for you.

If you have any questions or concerns about physical exercise, speak to your healthcare team.

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There are several patient organizations you can visit online for more information and resources for people affected by TGCT. Click here to find out more.

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CSF1, colony stimulating factor 1; D-TGCT, diffuse-type TGCT; GCTTS, giant cell tumor of tendon sheath; MRI, magnetic resonance imaging; N-TGCT, nodular-type TGCT; PVNS, pigmented villonodular synovitis; TGCT, tenosynovial giant cell tumor.

References:

  1. Stacchiotti S, et al. Cancer Treat Rev. 2023;112:102491.
  2. National Cancer Institute. Definition of non-malignant. Available at: https://www.cancer.gov/publications/dictionaries/cancer-terms/def/nonmalignant. Accessed: October 2026.
  3. Stefanou N, et al. Cureus. 2025;17(9):e92785.
  4. Ansel S, et al. J Med Case Rep. 2023;17(1):419.
  5. Mastboom MJL, et al. Acta Orthop. 2017;88(6):688–94.
  6. Worldometer. Europe Population (Live). Available at: https://www.worldometers.info/world-population/europe-population/. Accessed: October 2026.
  7. Stern S, et al. Future Oncol. 2025;21(12):1501–1510.
  8. Choi WS, et al. Cancers (Basel). 2024;16(2):402.
  9. Tap WD, Healey JH. Tumour Biol. 2022;44(1):239–248.
  10. NHS. Biopsy. Available at: https://www.nhs.uk/tests-and-treatments/biopsy/. Accessed: October 2026.
  11. Bernthal NM, et al. Orphanet J Rare Dis. 2021;16(1):191.
  12. Siegel M, et al. PLoS One. 2021;16(12):e0260795.
  13. Palmerini E, et al. Eur J Cancer. 2015;51(2):210–7.
  14. Ehrenstein V, et al. J Rheumatol. 2017;44(10):1476–83.
  15. Lopez-Bastida J, et al. Orphanet J Rare Dis. 2021;16(1):294.
  16. Gioia C, et al. Nutrients. 2020;12(5):1456.
  17. TGCT Support. About TGCT. Available at: https://www.tgctsupport.org/about-tgct.html. Accessed: October 2026.
  18. NHS. Joint pain. Available at: https://www.nhs.uk/symptoms/joint-pain/. Accessed: October 2026.
  19. NHS. Physical exercise. Available at: https://www.nhs.uk/live-well/exercise/exercise-health-benefits/. Accessed: October 2026.
  20. Dutta S, et al. Cureus. 2024;16(2):e54877.

DCPH-P03641 | October 2026