Registry Data Provide Insight Into Ultra-Rare Pediatric Tenosynovial Giant Cell Tumors

The double challenge of nonspecific symptoms and limited treatment options often leaves children with TGCT facing delayed diagnosis and high disease burden.

Two large studies of patients with tenosynovial giant cell tumors (TGCT), based on data collected by the international TGCT Support Registry and recently published in Future Oncology and Orphanet Journal of Rare Diseases, offer clinicians new insights into patients with this rare and impactful condition.

TGCT, an aggressive but benign tumor condition that primarily affects the joints and bursae, has predominantly been considered an adult disease. After publishing registry-based insights into adult disease in Future Oncology, the research team leveraged the data to better understand the pediatric experience of the disease, from diagnosis — which takes more than 12 months after symptom presentation for nearly two-thirds (62.3%) of pediatric patients — to its impact on quality of life and common treatment pathways.

Thomas Scharschmidt, MD

“This is an underappreciated diagnosis in pediatrics, so we wanted to define the problem in kids and learn how it is treated,” says Thomas J. Scharschmidt, MD, director of the Pediatric Orthopedic Oncology Program at Nationwide Children’s Hospital and a contributing author to both publications. “This is the largest and first database study, to our knowledge, exploring TGCT in the pediatric population, and it gave us rich information.”

The pediatric study included 122 patients and revealed that the most common symptoms of TGCT were swelling, pain and limited range of motion in the affected joint or joints. These nonspecific symptoms often resulted in diagnoses of Baker’s cysts, sports injuries and juvenile rheumatoid arthritis prior to TGCT.

Most patients are diagnosed and managed by orthopedic surgeons rather than orthopedic oncologists, but rheumatologists, primary care physicians and other health care providers often encounter patients on the diagnostic journey. Once patients have the right diagnosis, treatment is usually swift; the majority receive therapy or surgery within 3 months, while less serious cases may be monitored without treatment.

“We need to increase awareness and keep this in mind as we do our differential diagnosis,” says Dr. Scharschmidt. “If a child has no good reason for a painful, swollen joint, they need appropriate imaging early on; an MRI can get them started down the pathway to revealing this underlying problem.”

The knee was the most common site of tumors in both localized and diffuse TGCT cases. Surgery to remove the tumor was the most frequently employed treatment, with patients undergoing an average of 3.4 and 1.8 surgeries for diffuse and localized TGCT, respectively, due to recurrent disease. About 17% of patients were prescribed systemic therapy off-label.

“We are learning from the adult population that treating with FDA-approved systemic agents may lead to better quality of life, but these aren’t available on-label for pediatric patients,” says Dr. Scharschmidt, who first began studying the adult TGCT population during his time at The Arthur G. James Cancer Hospital and Richard J. Solove Research Institute at The Ohio State University Medical Center.

Encountering the condition among children at Nationwide Children’s orthopedic oncology program made him eager to contribute to advancing the understanding of the condition in pediatrics. There are currently two FDA-approved therapies available for adults, and he is hopeful that the study results and increased awareness will make clinical trials in pediatric TGCT more feasible.

TGCT significantly interferes with activities, schooling and quality of life for young patients, largely due to the pain and limitations in range of motion caused by the tumor and its symptoms. Pediatric patients report having to miss fun activities and adjust their expectations for sports, schooling, careers and social experiences due to their symptoms.

“It can have a significant effect on quality of life and activities of daily living, making the disease burden relatively high,” says Dr. Scharschmidt. Disease recurs in more than 50% of patients after surgery, demanding long-term follow-up imaging for at least a few years. “Patients should be treated at centers with a high volume of TGCT cases — we’re learning their outcomes are better when physicians frequently treat this condition.”

References:

1. Stern S, McKenzie PF, Bernthal N, O’Neill S, Palmerini E, Randall RL, Tap W, Scharschmidt T, Rothschild S. Localized and diffuse tenosynovial giant cell tumor: real-world results from a patient observational registry. Future Oncol. 2025 May;21(12):1501-1510.
2. Stern S, McKenzie PF, Baldi GG, Scharschmidt TJ, Palmerini E, Rothschild S. Pediatric patients with tenosynovial giant cell tumor: real-world evidence from an observational registry. Orphanet J Rare Dis. Published online January 30, 2026.

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