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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Oncology

Understanding Tenosynovial Giant Cell Tumor (TGCT): Basics and Terminology

At a Glance

Tenosynovial Giant Cell Tumor (TGCT) is a rare, non-cancerous, but locally aggressive joint tumor. Formerly known as PVNS or GCTTS, it comes in two main types: localized and diffuse. It does not spread to other organs but can damage nearby bone and cartilage if left untreated.

Receiving a diagnosis of a “tumor” is inherently frightening, especially when that tumor is rare and goes by several different names. If you have been searching for answers online, you may have encountered a confusing array of terms like Pigmented Villonodular Synovitis (PVNS) or Giant Cell Tumor of the Tendon Sheath (GCTTS).

It is important to know that the medical community has moved toward a unified name for these conditions: Tenosynovial Giant Cell Tumor (TGCT) [1]. This shift was formalized by the World Health Organization (WHO) to clear up confusion and ensure that patients and doctors are using the same language to describe this disease family [1].

Three Stabilizing Facts

When processing this diagnosis, it can help to anchor yourself in these three clinical realities:

  1. It is Rare: TGCT is not a common condition. The “localized” version affects about 30 people per million each year, while the “diffuse” version is even rarer, affecting about 8 people per million [2][3].
  2. It is Benign: In medical terms, benign means the tumor is not a typical cancer that spreads (metastasizes) to distant organs like the lungs or brain [1][4].
  3. It is Locally Aggressive: While it doesn’t spread throughout the body, TGCT is “locally aggressive,” meaning it can grow into the spaces around a joint, potentially damaging nearby bone, tendons, or cartilage if left unchecked [5][6].

Why the Name Changed

Historically, doctors named these tumors based on where they were found or what they looked like under a microscope.

  • PVNS usually referred to the “diffuse” type found in large joints like the knee or hip.
  • GCTTS usually referred to the “localized” type often found in the fingers or toes.

Today, the WHO 5th Edition classification prefers the umbrella term TGCT for both [1]. This is because research has shown that all these variations share the same underlying cause: a genetic “glitch” that causes an overproduction of a protein called CSF1 (Colony Stimulating Factor 1) [7][8]. This protein acts like a magnet, attracting certain inflammatory cells that clump together to form the tumor [7][9].

Localized vs. Diffuse: The Two Main Types

Your treatment and outlook will depend heavily on which type of TGCT you have. You can learn more about this in the Localized vs. Diffuse TGCT section.

Feature Localized TGCT (L-TGCT) Diffuse TGCT (D-TGCT)
Appearance A solitary, well-defined nodule [10]. An infiltrative growth that spreads through the joint lining [2].
Location Mostly small joints (fingers, toes) [10]. Mostly large joints (knee, hip, shoulder) [10][2].
Recurrence Averages around 10%, with studies showing a range of 5% to 15% [2][11]. Higher risk of coming back, ranging from 30% to 50% or more depending on complexity [6][12].

Understanding “Locally Aggressive”

The term “locally aggressive” describes how the tumor behaves within its home joint. Because TGCT grows from the synovium (the lining of the joint) or tendon sheaths (the protective sleeves around tendons), it can wrap around vital structures [13].

Doctors use MRI (Magnetic Resonance Imaging) as the “gold standard” to see exactly how aggressive a tumor is [5][14]. They look for osseous erosions, which are small “pits” or holes the tumor has worn into the bone [15]. Identifying these early helps your care team plan a strategy to protect your joint function and reduce the risk of the tumor returning [16][6].

While the term “tumor” is heavy, understanding that TGCT is a manageable, non-spreading condition is the first step in taking control of your care.

Common questions in this guide

What is the difference between TGCT, PVNS, and GCTTS?
They are different names for the same condition. The medical community now uses Tenosynovial Giant Cell Tumor (TGCT) as the official umbrella term, replacing older names like Pigmented Villonodular Synovitis (PVNS) and Giant Cell Tumor of the Tendon Sheath (GCTTS).
Is Tenosynovial Giant Cell Tumor considered cancer?
No, TGCT is a benign condition, meaning it is not a typical cancer that spreads to distant organs. However, it is considered locally aggressive because it can damage the cartilage, bone, and tendons in the specific joint where it grows.
What is the difference between localized and diffuse TGCT?
Localized TGCT usually appears as a single nodule in smaller joints like fingers or toes and has a lower chance of returning. Diffuse TGCT spreads more widely throughout the joint lining, usually in larger joints like knees or hips, and has a higher risk of recurrence.
How does a doctor determine how aggressive my TGCT is?
Doctors use an MRI scan as the gold standard to evaluate how aggressive the tumor is. They specifically look for osseous erosions, which are small pits or holes the tumor has worn into the nearby bone, to help plan your treatment.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my imaging, do I have the localized or the diffuse type of TGCT?
  2. 2.Does my MRI show any evidence of osseous erosions or damage to the bone near the tumor?
  3. 3.What is the estimated risk of recurrence for my specific type of TGCT after surgery?
  4. 4.Since this is a rare condition, how many patients with TGCT have you personally treated?

Questions For You

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References

References (16)
  1. 1

    Tenosynovial Giant-Cell Tumors of the Foot and Ankle: A Critical Analysis Review.

    Fraser EJ, Sullivan M, Maclean F, Nesbitt A

    JBJS reviews 2017; (5(1)) doi:10.2106/JBJS.RVW.16.00025.

    PMID: 28135228
  2. 2

    Higher incidence rates than previously known in tenosynovial giant cell tumors.

    Mastboom MJL, Verspoor FGM, Verschoor AJ, et al.

    Acta orthopaedica 2017; (88(6)):688-694 doi:10.1080/17453674.2017.1361126.

    PMID: 28787222
  3. 3

    Tenosynovial Giant Cell Tumor: Incidence, Prevalence, Patient Characteristics, and Recurrence. A Registry-based Cohort Study in Denmark.

    Ehrenstein V, Andersen SL, Qazi I, et al.

    The Journal of rheumatology 2017; (44(10)):1476-1483 doi:10.3899/jrheum.160816.

    PMID: 28765257
  4. 4

    Locally Aggressive Connective Tissue Tumors.

    Gounder MM, Thomas DM, Tap WD

    Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2018; (36(2)):202-209 doi:10.1200/JCO.2017.75.8482.

    PMID: 29220303
  5. 5

    Giant cell tumor of the tendon sheath: Magnetic resonance imaging findings in 38 patients.

    Wang C, Song RR, Kuang PD, et al.

    Oncology letters 2017; (13(6)):4459-4462 doi:10.3892/ol.2017.6011.

    PMID: 28599446
  6. 6

    Surgical management of 144 diffuse-type TGCT patients in a single institution: A 20-year cohort study.

    Spierenburg G, van der Heijden L, Mastboom MJL, et al.

    Journal of surgical oncology 2022; (126(6)):1087-1095 doi:10.1002/jso.26991.

    PMID: 35736790
  7. 7

    Tenosynovial giant cell tumor.

    Kager M, Kager R, Fałek P, et al.

    Folia medica Cracoviensia 2022; (62(2)):93-107 doi:10.24425/fmc.2022.141702.

    PMID: 36256897
  8. 8

    Medical Management of Tenosynovial Giant Cell Tumor.

    Palmerini E, Trent JC, Hornicek FJ

    Current oncology reports 2025; (27(7)):844-855 doi:10.1007/s11912-025-01679-x.

    PMID: 40392406
  9. 9

    Identification of potential diagnostic biomarkers for tenosynovial giant cell tumour by integrating microarray and single-cell RNA sequencing data.

    Chen C, Zheng L, Zeng G, et al.

    Journal of orthopaedic surgery and research 2023; (18(1)):905 doi:10.1186/s13018-023-04279-2.

    PMID: 38017559
  10. 10

    MRI of diffuse-type tenosynovial giant cell tumour in the knee: a guide for diagnosis and treatment response assessment.

    Spierenburg G, Suevos Ballesteros C, Stoel BC, et al.

    Insights into imaging 2023; (14(1)):22 doi:10.1186/s13244-023-01367-z.

    PMID: 36725759
  11. 11

    Recurrence of pigmented villonodular synovitis of the knee: A case report with review of literature on the risk factors causing recurrence.

    Fang Y, Zhang Q

    Medicine 2020; (99(16)):e19856 doi:10.1097/MD.0000000000019856.

    PMID: 32312009
  12. 12

    Tenosynovial giant cell tumours of the foot and ankle: a retrospective single centre experience with surgical treatment of 34 cases.

    Scheele C, Harrasser N, Beischl S, et al.

    BMC cancer 2025; (25(1)):530 doi:10.1186/s12885-025-13921-7.

    PMID: 40122811
  13. 13

    Tenosynovial Giant Cell Tumours: A Clinicopathologic Study of a Case-Series.

    Djiwa T, Bombone M, Sama B, et al.

    Sage open pathology 2025; (18()):30502098251341137 doi:10.1177/30502098251341137.

    PMID: 40519327
  14. 14

    Pigmented villonodular synovitis of the hip joint: Three cases demonstrating characteristic MRI features.

    Sullivan CJ, Eustace SJ, Kavanagh EC

    Radiology case reports 2020; (15(8)):1335-1338 doi:10.1016/j.radcr.2020.05.067.

    PMID: 32617126
  15. 15

    The Impact of Osseous Erosions on Intraarticular Tenosynovial Giant Cell Tumors of the Knee and Local Recurrence.

    Olson J, LiBrizzi CL, Gross J, et al.

    Orthopedics 2025; (48(6)):e238-e244 doi:10.3928/01477447-20251103-01.

    PMID: 41337552
  16. 16

    Diffuse-Type Tenosynovial Giant Cell Tumor: What Are the Important Findings on the Initial and Follow-Up MRI?

    Choi WS, Lee SK, Kim JY, Kim Y

    Cancers 2024; (16(2)) doi:10.3390/cancers16020402.

    PMID: 38254890

This page provides basic educational information about Tenosynovial Giant Cell Tumor (TGCT) terminology and types. It is not a substitute for professional medical advice, diagnosis, or treatment from your orthopedic specialist.

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