# Pediatric patients with tenosynovial giant cell tumor: real-world evidence from an observational registry

## TL;DR

This study examines the real-world impact of tenosynovial giant cell tumor in children, revealing higher misdiagnosis rates and significant disease burden compared to adults.

## Contribution

The study provides the first real-world evidence on pediatric tenosynovial giant cell tumor patients from a large observational registry.

## Key findings

- Pediatric patients were more likely to be misdiagnosed and had longer delays in diagnosis compared to adults.
- Diffuse TGCT in children required more surgeries and had higher recurrence rates than localized TGCT.
- Systemic therapies were rarely used in pediatric patients despite similar consultation rates with medical oncologists as adults.

## Abstract

Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive tumor originating in the synovial lining of the joint, bursa, and tendon sheath. TGCT typically affects individuals between 20 and 50 years of age and pediatric cases are considered ultra-rare. Research and clinical trials thus far have been largely focused on the adult TGCT population. Therefore, data are needed to understand the impact of TGCT on pediatric patients’ quality of life and any differences between adults. Here we report the result of the pediatric TGCT population enrolled in an observational patient registry.

A total of 122 pediatric patients (9.5%) were included in this exploratory, cross-sectional analysis of a longitudinal 1,278-patient registry from October 06, 2022 to November 26, 2024. Among pediatric patients, 73.0% had diffuse TGCT (D-TGCT; n = 89), 16.4% had localized TGCT (L-TGCT; n = 20), and 10.6% had unspecified TGCT (n = 13). Pediatric patients had a median age at diagnosis of 14.5 years.

More than half of pediatric patients were initially misdiagnosed and were more likely to be misdiagnosed than adults (62.3% vs. 49.9%, p < 0.01) and received joint aspirations significantly more frequently than adult patients (47.5% [n = 58] vs. 22.5% [n = 112], p < 0.05). Most pediatric patients were diagnosed by orthopedic surgeons (n = 79, 64.8%), and 52.5% of pediatric patients were diagnosed ≥ 1 years after symptom onset. Pediatric patients with D-TGCT underwent an average of 3.4 surgeries, compared to 1.8 surgeries for those with L-TGCT. Recurrence rates were similar among adults and pediatric patients with 66.3% of pediatric patients with D-TGCT having ≥ 1 post-operative recurrence compared to 15.0% of L-TGCT pediatric patients, respectively. Despite no approved systemic therapies for pediatric use, pediatric and adult patients consulted medical oncologists in similar rates and systemic therapies were prescribed similarly but infrequently overall (n = 21, 17.2% in pediatric patients and n = 95, 19.1% in adults).

Pediatric patients had significant disease burden, as compared to adults with TGCT, which severely affected their quality of life. The reliance on surgical treatment and underuse of multidisciplinary care emphasizes the unmet need for provider education and treatment advancements tailored to this population.

This study was an analysis of an observational patient registry and therefore was not registered as a clinical trial; no trial registration number is available. The study protocol was approved by Advarra (protocol reference number: Pro00077310). Patient enrollment for this analysis occurred from October 6, 2022, to November 26, 2024.

The online version contains supplementary material available at 10.1186/s13023-026-04231-7.