A multidisciplinary approach to giant cell tumors of tendon sheath and synovium--a critical appraisal of literature and treatment proposal

Giant Cell Tumor in Tarsal Midfoot Bones: A Case Report

Diffuse tenosynovial giant cell tumor (D-TGCT), previously known as pigmented villonodular synovitis (PVNS), is a benign, aggressive, and distracting proliferative synovial lesion. D-TGCT is commonly seen in large joints such as the knee and hip. We present the case of a 57-year-old female who initially presented with swelling on the left midfoot that increased over four years. Clinically, a ganglion was suspected on the left midfoot and an MRI showed a heterogeneous lobulated soft tissue mass on the superior aspect of the tarsal midfoot measuring 5.8 x 2.4 x 4.2 cm. The mass causing remodeling and bony erosion was more appreciated at the medial aspect of the talus bone and extended to the sinus tarsi and talocalcaneal joint space. Surgical excision of the mass was performed, and pathology reports found lobulated soft tissue lesions composed of mononuclear cells, multinucleated giant cells, sheets of foamy macrophages, inflammatory cells, and hemosiderin-laden macrophages. This case represents D-TGCT without atypia or malignancy based on the findings.

Real-world drug utilization and treatment patterns in patients with tenosynovial giant cell tumors in the USA

Aim: Real-world treatment patterns in tenosynovial giant cell tumor (TGCT) patients remain unknown. Pexidartinib is the only US FDA-approved treatment for TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Objective: To characterize drug utilization and treatment patterns in TGCT patients. Methods: In a retrospective observational study using IQVIA's linked prescription and medical claims databases (2018-2021), TGCT patients were stratified by their earliest systemic therapy claim (pexidartinib [N = 82] or non-FDA-approved systemic therapy [N = 263]). Results: TGCT patients treated with pexidartinib versus non-FDA-approved systemic therapies were predominantly female (61 vs 50.6%) and their median age was 47 and 54 years, respectively. Pexidartinib-treated patients had the highest 12-month probability of remaining on treatment (54%); 34.1% of pexidartinib users had dose reduction after their first claim. Conclusion: This study provides new insights into the unmet need, utilization and treatment patterns of systemic therapies for the treatment of TGCT patients.

Tenosynovial giant cell tumours: experience at an Australian tertiary referral centre for musculoskeletal tumours with minimum two-year follow-up

Aims

Tenosynovial giant cell tumour (TGCT) is a rare benign tumour of the musculoskeletal system. Surgical management is fraught with challenges due to high recurrence rates. The aim of this study was to describe surgical treatment and evaluate surgical outcomes of TGCT at an Australian tertiary referral centre for musculoskeletal tumours and to identify factors affecting recurrence rates.

Methods

A prospective database of all patients with TGCT surgically managed by two orthopaedic oncology surgeons was reviewed. All cases irrespective of previous treatment were included and patients without follow-up were excluded. Pertinent tumour characteristics and surgical outcomes were collected for analysis.

Results

There were 111 total cases included in the study; 71 (64%) were female, the mean age was 36 years (SD 13.6), and the knee (n = 64; 57.7%) was the most commonly affected joint. In all, 60 patients (54.1%) had diffuse-type (D-TGCT) disease, and 94 patients (84.7%) presented therapy-naïve as "primary cases" (PC). The overall recurrence rate was 46.8% for TGCT. There was a statistically significant difference in recurrence rates between D-TGCT and localized disease (75.0% vs 13.7%, relative risk (RR) 3.40, 95% confidence interval (CI) 2.17 to 5.34; p < 0.001), and for those who were referred in the "revision cases" (RC) group compared to the PC group (82.4% vs 48.9%, RR 1.68, 95% CI 1.24 to 2.28; p = 0.011). Age, sex, tumour volume, and mean duration of symptoms were not associated with recurrence (p > 0.05).

Conclusion

Recurrence rates remain high even at a tertiary referral hospital. Highest rates are seen in D-TGCT and "revision cases". Due to the risks of recurrence, the complexity of surgery, and the need for adjuvant therapy, this paper further supports the management of TGCT in a tertiary referral multi-disciplinary orthopaedic oncology service.

Prediction of local recurrence in tenosynovial giant cell tumor of the knee: Based on preoperative MRI evaluation into disease subtypes and severity

OBJECTIVE

Tenosynovial giant cell tumors (TSGCTs) of the knee differ in their clinical outcome according to disease subtypes and severity. The aim of this study was to determine the predictive MRI features related to local recurrence in TSGCT of the knee regarding disease subtypes and severity.

METHODS

This retrospective study included 20 patients with pathology-proven TSGCT of the knee who underwent preoperative MRI and surgery from Jan. 2007 to Jan. 2022. The anatomical point of the lesion was determined with a knee mapping. And then MRI features related to disease subtype including nodularity (single vs. multinodular); margin (circumscribed vs. infiltrative); peripheral hypointenseity (present vs. absent); internal hypointensity reflecting hemosiderin deposition (speckled vs. granular) were assessed. Third, MRI features related to disease severity including involvement of bone, cartilage, and tendon were evaluated. MRI features for predicting local recurrence of TSGCT were tested using chi-square test and logistic regression analysis.

RESULTS

Ten patients with diffuse-type TSGCT (D-TSGCT) and 10 patients with localized-type TSGCT (L-TSGCT) were included. There were six cases of local recurrence and all of them were D-TSGCT and none for L-TSGCT with statistical difference (P = 0.015). D-TSGCT that was direct risk factor for local recurrence showed more multinodular (80.0% vs. 10.0%; P = 0.007), infiltrative margin (90.0% vs. 10.0%; P = 0.002), and absent peripheral hypointensity (100.0% vs. 20.0%; P = 0.001) than L-TSGCT. Multivariate analysis showed infiltrative margin (odds ratio [OR], 81.0; P = 0.003) was independent MRI factor for D-TSGCT. Disease severity for risk of local recurrence included cartilage (66.7% vs. 7.1%; P = 0.024) and tendon (100.0% vs. 28.6%; P = 0.015) involvement compared to no local recurrence. Multivariate analysis showed tendon involvement (OR, 12.5; P = 0.042) was predictive MRI parameter for local recurrence. By combining tumor margin and tendon involvement, local recurrence was predicted sensitively on preoperative MRI (sensitivity, 100%; specificity, 50%; accuracy, 65%).

CONCLUSION

D-TSGCTs was associated with local recurrence and showed multinodularity infiltrative margin, and absent peripheral hypointensity. Disease severity including cartilage and tendon involvement was associated with local recurrence. Preoperative MRI evaluation by combining disease subtypes and severity can predict local recurrence sensitively.

Tenosynovial Giant Cell Tumor Observational Platform Project (TOPP) Registry: A 2-Year Analysis of Patient-Reported Outcomes and Treatment Strategies

BACKGROUND

The Tenosynovial giant cell tumor Observational Platform Project (TOPP) registry is an international prospective study that -previously described the impact of diffuse-type tenosynovial giant cell tumour (D-TGCT) on patient-reported outcomes (PROs) from a baseline snapshot. This analysis describes the impact of D-TGCT at 2-year follow-up based on treatment strategies.

MATERIAL AND METHODS

TOPP was conducted at 12 sites (EU: 10; US: 2). Captured PRO measurements assessed at baseline, 1-year, and 2-year follow-ups were Brief Pain Inventory (BPI), Pain Interference, BPI Pain Severity, Worst Pain, EQ-5D-5L, Worst Stiffness, and -Patient-Reported Outcomes Measurement Information System. Treatment interventions were no current/planned treatment (Off-Treatment) and systemic treatment/surgery (On-Treatment).

RESULTS

A total of 176 patients (mean age: 43.5 years) were included in the full analysis set. For patients without active treatment strategy -(Off-Treatment) at baseline (n = 79), BPI Pain Interference (1.00 vs. 2.86) and BPI Pain Severity scores (1.50 vs. 3.00) were numerically favorable in patients remaining Off-Treatment compared with those who switched to an active treatment strategy at year 1. From 1-year to 2-year -follow-ups, patients who remained Off-Treatment had better BPI Pain Interference (0.57 vs. 2.57) and Worst Pain (2.0 vs. 4.5) scores compared with patients who switched to an alternative treatment strategy. In addition, EQ-5D VAS scores (80.0 vs. 65.0) were higher in patients who remained -Off-Treatment between 1-year and 2-year follow-ups compared with patients who changed treatment strategy. For patients receiving systemic treatment at baseline, numerically favorable scores were seen in patients remaining on systemic therapy at 1-year follow-up: BPI Pain Interference (2.79 vs. 5.93), BPI Pain Severity (3.63 vs. 6.38), Worst Pain (4.5 vs. 7.5), and Worst Stiffness (4.0 vs. 7.5). From 1-year to 2-year follow-up, EQ-5D VAS scores (77.5 vs. 65.0) were higher in patients who changed from systemic treatment to a different treatment strategy.

CONCLUSION

These findings highlight the impact D-TGCT has on patient quality of life, and how treatment strategies may be influenced by these outcome measures. (ClinicalTrials.gov number: NCT02948088).

Understanding the Effect of Osteoarthritis on Surgical Treatment Patterns, Healthcare Resource Utilization, and Costs Among Patients With Tenosynovial Giant Cell Tumors

BACKGROUND

Tenosynovial giant cell tumor (TGCT) may be misdiagnosed as osteoarthritis (OA), or the chronic course of TGCT may lead to development of secondary OA. However, little is known about the effect of comorbid OA on long-term surgical patterns and costs among TGCT patients.

METHODS

This cohort study used claims data from the Merative MarketScan Research Databases. The study included adults diagnosed with TGCT from January 1, 2014, to June 30, 2019, who have at least 3 years of continuous enrollment before and after the first TGCT diagnosis (date of the first TGCT diagnosis = index date) and no other cancer diagnosis during the study period. Patients were stratified by the presence of an OA diagnosis relative to the index date. Outcomes included surgical procedure patterns, healthcare resource utilization, and costs in the 3-year pre- and postindex periods. Multivariable models were used to assess the effect of OA on the study outcomes, controlling for baseline characteristics.

RESULTS

The study included 2856 TGCT patients: 1153 (40%) had no OA before or after index (OA[-/-]), 207 (7%) had OA before index but not after (OA[+/-]), 644 (23%) had OA after index but not before (OA[-/+]), and 852 (30%) had OA before and after index (OA[+/+]). The mean age was 51.6 years, and 61.7% were female. During the postperiod, joint surgery was more common among OA(-/+) and OA(+/+) patients compared with OA(-/-) and OA(+/-) patients (55.7% vs 33.2%). The mean all-cause total costs in the 3-year postperiod were $19,476 per patient per year. Compared with OA(-/-) patients, OA(-/+) and OA(+/+) patients had a higher risk of undergoing recurrent surgery and higher total healthcare costs postindex.

DISCUSSION

Higher rates of surgery and increased healthcare cost observed in TGCT patients with postindex OA underscore the need for effective treatment options to reduce joint damage, especially among patients with comorbid OA.

Giant cell tumor of tendon sheath: A report of 216 cases

BACKGROUND

In this article on giant cell tumor of tendon sheath (GCTTS), we intend to summarize and analyze the clinical and pathological features of GCTTS hoping to improve clinical management and patient treatment.

METHODS

The study retrospectively reviewed 216 patients of GCTTS, registered at the Affiliated Hospital of Southwest Medical University from January 2010 to December 2020. These cases were diagnosed by surgical excision. The clinicopathological features and the prognosis were reviewed in the light of the current literature.

RESULTS

Of these 216 GCTTS patients, 72 were males (33.3%) and 144 females (66.7%), with a ratio male-to-female of 1:2. The patients' age ranged from 5 to 82, the average being 41.5 years at diagnosis. A total of 96 cases (44.4%) occurred in the hand region, followed by 35 cases (16.2%) in the knee, 32 cases (14.8%) in the foot, 25 cases (11.6%) in the ankle, 12 cases (5.6%) in the wrist, 12 cases (5.6%) in the leg, 2 cases (0.9%) in the head, 1 case (0.5%) in the forearm, and 1 case (0.5%) inside and outside the spinal channel. Histopathology mainly revealed large synovial-like monocytes, small monocytes, and osteoclast-like giant cells.

CONCLUSION

Our results confirm that GCTTS predominantly occurs in the hands of young women. Complete surgical resection with long-term follow-up is the preferred management.

A case report of arthroscopic treatment of a retro-patellar GCTTS causing anterior knee pain

INTRODUCTION AND IMPORTANCE

Giant cell tumor of tendon sheath (GCTTS) is a common soft tissue tumor in hands and feet; however, it is rare in knee joints.

CASE PRESENTATION

We present a case of a 52-year-old female who had a retropatellar tendon giant cell tumor (GCT) in the right knee, causing vague anterior knee pain.

CLINICAL DISCUSSION

Anterior knee pain is a challenging complaint in orthopedics due to the multiple causative reasons, the combination of several complex etiologies, and the lack of clear guidelines for an effective treatment.

CONCLUSION

This case report aims to shed light on unlikely pathologies in complex cases. GCTTS is a rare lesion to affect the retropatellar region. However, we must keep it in mind when dealing with challenging anterior vague knee pain complaints. A comprehensive examination is essential; surgical experience and extended follow-up are mandatory for avoiding complications.

Surgical treatment of spinal tenosynovial giant cell tumor: Experience from a single center and literature review

Introduction

Spinal tenosynovial giant cell tumor (TGCT) is a rare benign primary spinal tumor with aggressive behavior. The treatment strategy and prognosis of spinal TGCT remain unclear. This retrospective study aimed to evaluate the effectiveness of surgical treatment of spinal TGCT.

Methods

We enrolled 18 patients with spinal TGCT who underwent surgical treatment in our hospital between January 2002 and January 2021. Additionally, we reviewed 72 cases of spinal TGCT with surgical treatment reported in the previous literature. Therefore, a total of 90 cases of spinal TGCT were evaluated for their clinical characteristics, surgical details, radiotherapy, and prognosis.

Results

In terms of the extent of resection, 73 cases (81.1%) underwent gross total resection (GTR), and 17 cases (18.9%) underwent subtotal resection (STR). Regarding the technique of GTR, 12 cases (16.7%) underwent en bloc resection, while 60 cases (83.3%) underwent piecemeal resection. During a median follow-up duration of 36 months (range: 3-528 months), 17.8% (16/90) cases experienced local recurrence/progression. The local recurrence/progression rate in cases that underwent GTR was 8.2% (6/73), which was significantly lower than that in cases with STR (58.8%, 10/17) (p<0.001). The local recurrence/progression rate of en bloc resection was 8.3% (1/12), and that of piecemeal resection was 8.3% (5/60). Twelve cases underwent perioperative adjuvant radiotherapy, and one (8.3%, 1/12) of them showed disease progression during follow-up. Six recurrent/progressive lesions were given radiotherapy and all of them remained stable in the subsequent follow-up. Eight recurrent/progressive lesions were only treated with re-operation without radiotherapy, and half of them (50.0%, 4/8) demonstrated repeated recurrence/progression in the subsequent follow-up.

Conclusion

Surgical treatment could be effective for spinal TGCT cases, and GTR is the preferred surgical strategy. Piecemeal resection may be appropriate for spinal TGCT cases with an acceptable local recurrence/progression rate. Perioperative adjuvant radiotherapy may reduce the risk of postoperative local recurrence/progression, and radiotherapy plays an important role in the treatment of recurrent/unresectable spinal TGCT lesions.

Radiosynoviorthesis: almost seventy years of experience but still somewhat fameless

Radiosynoviorthesis (RSO) or radiation synovectomy has been practiced for more than half a century, but in many parts of the world, it is still relatively unknown and not used to its full potential in the standard care for chronic, persistent or recurrent synovitis. The working mechanism of RSO is simple yet elegant. Radiopharmaceutical particles are, after injection in the affected synovial joint, gobbled up by phagocytizing subsynovial inflammatory cells. As a consequence, the synovium will be irradiated locally resulting in synovial cell necrosis and inhibition of cell proliferation, which eventually leads to a decrease in the inflammatory response in the joint cavity. In this review RSO is once again brought to the attention and common indications for RSO are discussed. Also, appropriate activities of the administrated radiopharmaceuticals and coadministrated glucocorticoids are provided. Furthermore, a detailed database-assisted chronological overview of published literature of RSO in inflammatory and non-inflammatory diseases, like rheumatoid arthritis, psoriatic arthritis, osteoarthritis and osteochrondomatosis, hemophilic hemarthrosis and pigmented villonodular synovitis (PVNS) is provided. Based upon the published literature an indication of level of evidence of RSO is discussed. There is evidence that RSO is effective in persistent synovitis in patients with a variety of causes for synovitis, although the effectiveness seems to decrease over time. In these patients, RSO may not be used to its full potential in many parts of the world. Results in of RSO in hemophilia patients with hemarthrosis are favourable, however the evidence for the effectiveness of RSO in these patients is less firm and mainly based on case series. The evidence for the efficacy of RSO as adjuvant therapy in PVNS is, at best, of very low quality.

Long-term follow-up of nilotinib in patients with advanced tenosynovial giant cell tumours: Long-term follow-up of nilotinib in TGCT

BACKGROUND

Diffuse-type tenosynovial giant cell tumour (D-TGCT) is a non-malignant but locally aggressive tumour driven by overexpression of colony-stimulating factor-1 (CSF1). CSF1R inhibitors are potential therapeutic strategies for patients not amenable to surgery. We report here the long-term outcome of nilotinib in patients with advanced D-TGCT treated within a phase II prospective international study (ClinicalTrials.gov: NCT01261429).

METHODS

Patients were enrolled between December 2010-September 2012 at 11 cancer centres. Eligible patients had histologically confirmed D-TGCT, not amenable to surgery. Patients received nilotinib until evidence of progression, toxicity or a maximum of one year. Long-term data were retrospectively collected after the completion of the phase II trial. Patients with nilotinib treatment ≥12 weeks and follow-up ≥12 months were included for long-term analysis.

RESULTS

Forty-eight of 56 enrolled patients were included. Median treatment duration was 11 months; 31 (65%) patients completed the treatment protocol. After 102 months of follow-up (median; range 12-129), 25 patients (52%) had progression. The median progression-free survival (PFS) was 77 months. The five-year PFS rate was 53%. Fifteen patients (n = 15/46; 33%) experienced clinical worsening after 11 months (median). Twenty-seven patients (58%) received additional treatment, after which eleven patients (n = 11/27; 41%) had a second relapse. Nine patients required a subsequent treatment, primarily other CSF1R inhibitors (n = 6/9; 67%). No unfavourable long-term effects were observed.

CONCLUSION

This long-term analysis of nilotinib for advanced D-TGCT showed that about half of the patients had progression and underwent additional treatment after 8.5 years follow-up. Contrarily, several patients had ongoing disease control after limited treatment duration, demonstrating the mixed effect of nilotinib.

Tenosynovial giant cell tumors (TGCT): molecular biology, drug targets and non-surgical pharmacological approaches

INTRODUCTION

Tenosynovial giant cell tumor (TGCT) is a mono-articular, benign or locally aggressive and often debilitating neoplasm. Systemic therapies are becoming part of the multimodal armamentarium when surgery alone will not confer improvements. Since TGCT is characterized by colony-stimulating factor-1 (CSF1) rearrangements, the most studied molecular pathway is the CSF1 and CSF1 receptor (CSF1R) axis. Inhibiting CSF1-CSF1R interaction often yields considerable radiological and clinical responses; however, adverse events may cause treatment discontinuation because of an unfavorable risk-benefit ratio in benign disease. Only Pexidartinib is approved by the US FDA; however, the European Medicines Agency has not approved it due to uncertainties on the risk-benefit ratio. Thus, there is a need for safer and effective therapies.

AREAS COVERED

Light is shed on disease mechanisms and potential drug targets. The safety and efficacy of different systemic therapies are evaluated.

EXPERT OPINION

The CSF1-CSF1R axis is the principal drug target; however, the effect of CSF1R inhibition on angiogenesis and the role of macrophages, which are essential in the postoperative course, needs further elucidation. Systemic therapies have a promising role in treating mainly diffuse-type, TGCT patients who are not expected to clinically improve from surgery. Future drug development should focus on targeting neoplastic TGCT cells.

Tenosynovial giant cell tumor, localized type, with recurrence, and lung metastases: A case report

Tenosynovial Giant Cell Tumors (TSGCT) are the second most frequent benign soft tissue tumor in the hand and wrist after ganglion cysts. The tumor arises from joint synovia and tendon sheaths. It is divided into 2 categories: localized and diffuse type. The well-circumscribed localized type usually responds nicely to single excision surgery. The diffuse type, on the other hand, has a proclivity for becoming an aggressive lesion. We reported a case of a 56-year-old woman who was experiencing shortness of breath as a result of lung metastases. A TSGCT, localized type, was found after radiology, and histology examination of the re-excised surgical lesion was done. This rare case demonstrates the possibility of lung metastases from tenosynovial giant cell tumor, localized type.

Surgical Treatment Patterns, Healthcare Resource Utilization, and Economic Burden in Patients with Tenosynovial Giant Cell Tumor Who Underwent Joint Surgery in the United States

Background: Tenosynovial giant cell tumors (TGCT) are rare and locally aggressive neoplasms in synovium, bursae, and tendon sheaths, which cause pain, joint dysfunction, and damage to the affected joints. Objective: To evaluate the surgical patterns and economic burden among patients with TGCT who underwent joint surgery in the United States. Methods: Patients newly diagnosed with TGCT, aged 18-64 years, who underwent joint surgery post-TGCT diagnosis were identified from the OptumHealth Care Solutions, Inc database (Q1/1999-Q1/2017). Patients were required to be continuously enrolled for ≥1 year before and ≥3 years after the first TGCT diagnosis (index date). Surgical patterns were assessed post-index. Healthcare resource utilization and associated healthcare costs, and indirect costs related to work loss in year 1, year 2, and year 3 post-index, were compared with those at baseline. Results: Of 835 eligible TGCT patients, 462 (55%) patients who had ≥1 joint surgery post-index were included. During a median follow-up of 5.7 years, 78% of patients underwent their first joint surgery in year 1 and 41% had ≥1 repeat surgery. Magnetic resonance imaging utilization was highest during baseline (46%) and declined afterward (28%, 17%, and 19% in years 1, 2, and 3, respectively). Opioids and nonsteroidal anti-inflammatory drugs (NSAIDs), and physical therapy, occupational therapy, and rehabilitation services, were commonly used during baseline (45%, 40%, and 30%, respectively). More patients used opioids in year 1 vs baseline (78% vs 45%; P<0.0001), while its utilization return to baseline levels in year 2 (41%) and year 3 (42%). A similar pattern was observed for NSAIDs and physical/occupational therapy/rehabilitation services. Healthcare resource utilization and associated healthcare costs surged in year 1 and returned to baseline or lower in years 2 and 3. A similar pattern was observed for indirect costs associated with work loss. Discussion: The high proportion of patients undergoing repeat surgeries and prevalent use of opioids, NSAIDs, and physical/occupational therapy/rehabilitation services suggests an unmet medical need after surgical treatment. Conclusions: Surgical resection alone might be inadequate to control TGCT. New treatment options may complement surgery and alleviate the clinical and economic burden experienced by patients with TGCT who had received prior surgery.

Update on Tenosynovial Giant Cell Tumor, an Inflammatory Arthritis With Neoplastic Features

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to joint destruction and bone erosion. Even if many treatments were developed with success in the last decades, some patients fail to respond, and disease chronicity is still a burden. Mechanisms involved in such resistance may include molecular changes in stromal cells. Other explanations can come from observations of tenosynovial giant cell tumor (TGCT), first considered as an inflammatory arthritis, but with unusual neoplastic features. TGCT leads to synovium hypertrophy and hyperplasia with hemosiderin deposition. It affects young adults, resulting in secondary osteoarthritis and increased morbidity. TGCT shows clinical, histological and genetic similarities with RA but affecting a single joint. However, the monoclonality of some synoviocytes, the presence of translocations and rare metastases also suggest a neoplastic disease, with some features common with sarcoma. TGCT is more probably in an intermediate situation between an inflammatory and a neoplastic process, with a main involvement of the proinflammatory cytokine CSF-1/CSF1R signaling axis. The key treatment option is surgery. New treatments, derived from the RA and sarcoma fields, are emerging. The tyrosine kinase inhibitor pexidartinib was recently FDA-approved as the first drug for severe TGCT where surgery is not an option. Options directly targeting the excessive proliferation of synoviocytes are at a preclinical stage.

Turalio risk evaluation and mitigation strategy for treatment of tenosynovial giant cell tumor: framework and experience

For drugs with enhanced serious safety risks, Risk Evaluation and Mitigation Strategy (REMS) may be required. Pexidartinib is approved for treatment of adult symptomatic tenosynovial giant cell tumor (TGCT) associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Its approval was conditional on its prescription via a mandatory REMS due to serious and potentially fatal liver injury seen in clinical trials. Turalio^® REMS aims to mitigate this risk by ensuring provider education on pexidartinib use and required REMS components, prescriber adherence to baseline and periodic monitoring, and enrolling patients in a registry to further assess safe use and acute, chronic and irreversible hepatotoxicity. Through Turalio REMS, benefits of treating patients with pexidartinib may be preserved.

A New Simple and Practical Clinical Classification for Tenosynovial Giant Cell Tumors of the Knee

Objective

To propose a simple and practical clinical classification for tenosynovial giant cell tumor (TGCT) of the knee.

Methods

A retrospective study was conducted to verify the value and significance of this clinical classification. TGCT growth patterns, knee joint capsule, and bone erosion were applied to establish this novel clinical classification. Seventy‐eight patients who underwent surgery for TGCT from 2008 to 2016 were identified. This novel clinical classification was retrospectively applied to patients' existing classification, and patients with different TGCT types were statistically compared to verify the significance of the clinical classification.

Results

The clinical classification included three types and four subtypes. Type 1: localized TGCT, Subtype 1a: localized intra‐articular TGCT, Subtype 1b: localized extra‐articular TGCT. Type 2: diffuse TGCT, Subtype 2a: diffuse intra‐articular TGCT with bone normal, Subtype 2b: diffuse intra‐articular TGCT with bone destruction. Type 3: diffuse TGCT across the knee joint capsule. The mean follow‐up time for the 78 patients was 59.6 months. Twenty‐one patients were in Subtype 1a, four were Subtype 1b, 38 were Subtype 2a, seven were Subtype 2b, and eight were Type 3. Oncological results and surgical complications differed significantly (P = 0.000, P = 0.000). The mean Musculoskeletal Tumor Society functional scores differed significantly at 27.8 for Type 1 patients, 22.9 for Type 2 patients, and 17.0 for Type 3 patients (P = 0.000).

Conclusions

This clinical classification can be easily used to evaluate TGCT of all knees prior to surgery or other treatments and can help determine surgical options.

Arthroscopic Versus Open Management of Diffuse-Type Tenosynovial Giant Cell Tumor of the Knee: A Meta-analysis of Retrospective Cohort Studies

Whether arthroscopic or open surgical management for diffuse-type tenosynovial giant cell tumor (D-TGCT) of the knee is associated with a lower rate of recurrence is unknown.

Giant Cell Tumor of Tendon Sheath in Knee Capsule

A giant cell tumor of the tendon sheath (GCTTS) is a benign, soft tissue (synovial membrane) tumor that frequently involves the fingers. However, the localized form of the GCTTS can be rarely seen in large joints such as knees, ankles, and shoulders. GCTTS may occur due to questionable etiology that includes inflammation, trauma, or chromosomal abnormalities. This is a case of a 30-year-old female, who presented with a painful mass in her right knee. Examination revealed a palpable, tender, slightly mobile mass lateral to the patella. MRI demonstrated a cystic lesion that underwent excision. Data from the reported cases imply that local recurrence was observed in 10%-20% of patients due to incomplete primary resection. Physicians should consider the likelihood of a GCTTS when an intra-articular knee prominence is found. Early diagnosis and appropriate treatment can help with rapid clinical improvement.

Atypical Tenosynovial Giant Cell Tumor of the Foot and Ankle: A Case Report

Tenosynovial giant cell tumor, also known as giant cell tumor of the tendon sheath (GCT-TS), is a solitary, nodular, firm, benign, soft-tissue tumor that arises from the synovial lining of a tendon. The etiology is unknown. It is a rare soft-tissue tumor, with an overall incidence of one in 50,000 individuals, and usually affects people aged between 30 and 50 years. Magnetic resonance imaging tends to be the imaging modality of choice, used for surgical preparation. Widely accepted treatment involves local excision with or without radiotherapy. The author presents a case study involving a patient with an abnormally large, longstanding GCT-TS, diagnosed with clinical examination and imaging modalities, surgically excised, and further confirmed by pathology reports. Topic of discussion includes a review of GCT-TS.

The diffuse-type tenosynovial giant cell tumor (dt-TGCT) patient journey: a prospective multicenter study

Background

Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive neoplasm arising from the synovium of joints, bursae, and tendon sheaths affecting small and large joints. It represents a wide spectrum ranging from minimally symptomatic to massively debilitating. Most findings to date are mainly from small, retrospective case series, and thus the morbidity and actual impact of this rare disease remain to be elucidated. This study prospectively explores the management of TGCT in tertiary sarcoma centers.

Methods

The TGCT Observational Platform Project registry was a multinational, multicenter, prospective observational study involving 12 tertiary sarcoma centers in 7 European countries, and 2 US sites. This study enrolled for 2 years all consecutive ≥ 18 years old patients, with histologically diagnosed primary or recurrent cases of diffuse-type TGCT. Patient demographic and clinical characteristics were collected at baseline and every 6 months for 24 months. Quality of life questionnaires (PROMIS-PF and EQ-5D) were also administered at the same time-points. Here we report baseline patient characteristics.

Results

166 patients were enrolled between November 2016 and March 2019. Baseline characteristics were: mean age 44 years (mean age at disease onset: 39 years), 139/166 (83.7%) had prior treatment, 71/166 patients (42.8%) had ≥ 1 recurrence after treatment of their primary tumor, 76/136 (55.9%) visited a medical specialist ≥ 5 times, 66/116 (56.9%) missed work in the 24 months prior to baseline, and 17/166 (11.6%) changed employment status or retired prematurely due to disease burden. Prior treatment consisted of surgery (i.e., arthroscopic, open synovectomy) (128/166; 77.1%) and systemic treatments (52/166; 31.3%) with imatinib (19/52; 36.5%) or pexidartinib (27/52; 51.9%). Treatment strategies at baseline visits consisted mainly of watchful waiting (81/166; 48.8%), surgery (41/166; 24.7%), or targeted systemic therapy (37/166; 22.3%). Patients indicated for treatment reported more impairment compared to patients indicated for watchful waiting: worst stiffness NRS 5.16/3.44, worst pain NRS 6.13/5.03, PROMIS-PF 39.48/43.85, and EQ-5D VAS 66.54/71.85.

Conclusion

This study confirms that diffuse-type TGCT can highly impact quality of life. A prospective observational registry in rare disease is feasible and can be a tool to collect curated-population reflective data in orphan diseases.

Name of registry: Tenosynovial Giant Cell Tumors (TGCT) Observational Platform Project (TOPP).

Trial registration number: NCT02948088.

Date of registration: 10 October 2016.

URL of Trial registry record: https://clinicaltrials.gov/ct2/show/NCT02948088?term=NCT02948088&draw=2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01820-6.

Management of tenosynovial giant cell tumour of the foot and ankle

AIMS

Tenosynovial giant cell tumour (TGCT) is one of the most common soft-tissue tumours of the foot and ankle and can behave in a locally aggressive manner. Tumour control can be difficult, despite the various methods of treatment available. Since treatment guidelines are lacking, the aim of this study was to review the multidisciplinary management by presenting the largest series of TGCT of the foot and ankle to date from two specialized sarcoma centres.

METHODS

The Oxford Tumour Registry and the Leiden University Medical Centre Sarcoma Registry were retrospectively reviewed for patients with histologically proven foot and ankle TGCT diagnosed between January 2002 and August 2019.

RESULTS

A total of 84 patients were included. There were 39 men and 45 women with a mean age at primary treatment of 38.3 years (9 to 72). The median follow-up was 46.5 months (interquartile range (IQR) 21.3 to 82.3). Localized-type TGCT (n = 15) predominantly affected forefoot, whereas diffuse-type TGCT (Dt-TGCT) (n = 9) tended to panarticular involvement. TGCT was not included in the radiological differential diagnosis in 20% (n = 15/75). Most patients had open rather than arthroscopic surgery (76 vs 17). The highest recurrence rates were seen with Dt-TGCT (61%; n = 23/38), panarticular involvement (83%; n = 5/8), and after arthroscopy (47%; n = 8/17). Three (4%) fusions were carried out for osteochondral destruction by Dt-TGCT. There were 14 (16%) patients with Dt-TGCT who underwent systemic treatment, mostly in refractory cases (79%; n = 11). TGCT initially decreased or stabilized in 12 patients (86%), but progressed in five (36%) during follow-up; all five underwent subsequent surgery. Side effects were reported in 12 patients (86%).

CONCLUSION

We recommend open surgical excision as the primary treatment for TGCT of the foot and ankle, particularly in patients with Dt-TGCT with extra-articular involvement. Severe osteochondral destruction may justify salvage procedures, although these are not often undertaken. Systemic treatment is indicated for unresectable or refractory cases. However, side effects are commonly experienced, and relapses may occur once treatment has ceased. Cite this article: Bone Joint J 2021;103-B(4):788-794.

Tenosynovial giant cell tumor of the distal tibiofibular joint

Tenosynovial giant cell tumors are extremely rare tumors with highly nonspecific symptoms. This benign but aggressive disease has a slow course of progression; however, it can ultimately lead to irreversible damage to a joint. Here we describe a case of a 45-year-old female with a diagnosis of tenosynovial giant cell tumors of the distal tibiofibular joint, the second case described in the literature for such location. Appropriate imaging studies and ultimately histologic studies are necessary for the correct diagnosis. Some locations are particularly unusual for these tumors making a high level of suspicion as well as treatment by an oncology orthopedic surgery specialist at a high-volume center paramount.

Patient-Derived Tumor Xenografts Plus Ex Vivo Models Enable Drug Validation for Tenosynovial Giant Cell Tumors

INTRODUCTION

Tenosynovial giant cell tumor (TGCT) is a locally aggressive tumor with colony-stimulating factor 1 receptor (CSF1R) signal expression. However, there is a lack of better in vivo and ex vivo models for TGCT. This study aims to establish a favorable preclinical translational platform, which would enable the validation of efficient and personalized therapeutic candidates for TGCT.

PATIENTS AND METHODS

Histological analyses were performed for the included patients. Fresh TGCT tumors were collected and sliced into 1.0-3.0 mm³ sections using a sterilized razor blade. The tumor grafts were surgically implanted into subrenal capsules of athymic mice to establish patient-derived tumor xenograft (PDTX) mouse models. Histological and response patterns to CSF1R inhibitors evaluations were analyzed. In addition, ex vivo cultures of patient-derived explants (PDEs) with endpoint analysis were used to validate TGCT graft response patterns to CSF1R inhibitors.

RESULTS

The TGCT tumor grafts that were implanted into athymic mice subrenal capsules maintained their original morphological and histological features. The "take" rate of this model was 95% (19/20). Administration of CSF1R inhibitors (PLX3397, and a novel candidate, WXFL11420306) to TGCT-PDTX mice was shown to reduce tumor size while inducing intratumoral apoptosis. In addition, the CSF1R inhibitors suppressed circulating nonspecific monocyte levels and CD163-positive cells within tumors. These response patterns of engrafts to PDTX were validated by ex vivo PDE cultures.

CONCLUSIONS

Subrenal capsule supports the growth of TGCT tumor grafts, maintaining their original morphology and histology. This TGCT-PDTX model plus ex vivo explant cultures is a potential preclinical translational platform for locally aggressive tumors, such as TGCT.

Endoscopic resection of a localized tenosynovial giant cell tumor causing posterior ankle impingement in a 15-year-old athlete: A case report

Tenosynovial giant cell tumor (TGCT) is a systematically benign but locally aggressive lesion arising from the synovium, tendon sheath or joint bursae. Even in athletes, soft tissue tumors may be the underlying reason or a component of posterior ankle impingement, although the most common mechanism is forceful and repetitive plantar flexion. In this article, we present a case of localized TGCT in a 15-year-old female patient presenting with symptoms of posterior ankle impingement. The preferred technique for treatment was complete local resection via posterior ankle endoscopy. The patient returned to sports at three months and no recurrence was observed on the last follow-up at the first postoperative year. Although rare, soft tissue tumors should be taken into consideration in posterior ankle impingement in athletes. Such benign soft tissue tumors in the posterior ankle can be treated safely and effectively via two-portal posterior endoscopic approach.

The effect of Imatinib Mesylate in diffuse-type Tenosynovial Giant Cell Tumours on MR imaging and PET-CT

INTRODUCTION

Recurrence rates remain high after surgical treatment of diffuse-type Tenosynovial Giant Cell Tumour (TGCT). Imatinib Mesylate (IM) blocks Colony Stimulating Factor1 Receptor (CSF1R), the driver mechanism in TGCT. The aim of this study was to determine if IM reduces the tumour metabolic activity evaluated by PET-CT and to compare this response with the response seen on MR imaging.

MATERIALS AND METHODS

25 Consecutive patients treated with IM (off label use) for locally advanced (N = 12) or recurrent (N = 13) diffuse-type TGCT were included, 15 male and median age at diagnosis 39 (IQR 31-47) years. The knee was most frequently affected (n = 16; 64%). The effect of IM was assessed pre- and post-IM treatment by comparing MR scans and PET-CT. MR scans were assessed by Tumour Volume Score (TVS), an estimation of the tumour volume as a percentage of the total synovial cavity. PET-CT scans were evaluated based on maximum standardized uptake value (SUV-max). Partial response was defined as more than 50% tumour reduction with TVS and a decrease of at least 30% on SUV-max.

RESULTS

Median duration of IM treatment was 7.0 (IQR 4.2-11.5) months. Twenty patients (80%) discontinued IM treatment for poor response or intended surgery. Twenty patients experienced an adverse event grade 1-2, three patients grade 3 (creatinine increment, neutropenic sepsis, liver dysfunction). MR assessment of all joints showed 32% (6/19) partial response and 63% (12/19) stable disease, with a mean difference of 12% (P = 0.467; CI -22.4-46.0) TVS between pre- and post-IM and a significant mean difference of 23% (P = 0.021; CI 4.2-21.6) in all knee lesions. PET-CT, all joints, showed a significantly decreased mean difference of 5.3 (P = 0.004; CI 1.9-8.7) SUV-max between pre- and post-IM treatment (58% (11/19) partial response, 37% (7/19) stable disease). No correlation between MR imaging and PET-CT could be appreciated in 15 patients with complete radiological data.

CONCLUSION

This study confirms the moderate radiological response of IM in diffuse-type TGCT. PET-CT is a valuable additional diagnostic tool to quantify response to tyrosine kinase inhibitor treatment. Its value should be assessed further to validate its efficacy in the objective measurement of biological response in targeted systemic treatment of TGCT.

Unusual Occurrence of Tenosynovial Giant Cell Tumor in Hoffa's Fat Pad: A Potential Differential Diagnosis for Nontraumatic Knee Swelling and Pain

A tenosynovial giant cell tumor (TGCT) is a benign lesion whose presence in Hoffa's pad has rarely been reported. This unique case report discusses a 33-year-old female patient who presented with swelling and pain in her left knee. Clinical and MRI findings were used to make the diagnosis, which was confirmed on a histopathological basis. The patient had a large tumor (5 × 3 × 3 cm) in Hoffa's fat pad, which was diagnosed as TGCT and managed with open resection due to its size. At follow-up after 20 months, the patient was asymptomatic, and there was no local recurrence of the tumor.

Surgical Treatment of Localized-Type Tenosynovial Giant Cell Tumors of Large Joints: A Study Based on a Multicenter-Pooled Database of 31 International Sarcoma Centers

BACKGROUND

Localized-type tenosynovial giant cell tumor (TGCT) is a rare, neoplastic disease with only limited data supporting treatment protocols. We describe treatment protocols and evaluate their oncological outcome, complications, and functional results in a large multicenter cohort of patients. A secondary study aim was to identify factors associated with local recurrence after surgical treatment.

METHODS

Patients with histologically proven localized TGCT of a large joint were included if they had been treated between 1990 and 2017 in 1 of 31 tertiary sarcoma centers. Of 941 patients with localized TGCT, 62% were female. The median age at initial treatment was 39 years, and the median duration of follow-up was 34 months. Sixty-seven percent of the tumors affected the knee, and the primary treatment at the tertiary center was 1-stage open resection in 73% of the patients. Proposed factors for predicting a first local recurrence after treatment in the tertiary center were tested in a univariate analysis, and those that demonstrated significance were subsequently included in a multivariate analysis.

RESULTS

The localized TGCT recurred in 12% of all cases, with local-recurrence-free rates at 3, 5, and 10 years of 88%, 83%, and 79%, respectively. The strongest factor for predicting recurrent disease was a prior recurrence (p < 0.001). Surgical treatment decreased pain and swelling in 71% and 85% of the patients, respectively, and such treatment was associated with complications in 4% of the patients. Univariate and multivariate analyses of the patients who had not undergone therapy previously yielded positive associations between local recurrence and a tumor size of ≥5 cm versus <5 cm (hazard ratio [HR] = 2.50; 95% confidence interval [CI] = 1.32 to 4.74; p = 0.005). Arthroscopy (versus open surgery) was significantly associated with tumor recurrence in the univariate analysis (p = 0.04) but not in the multivariate analysis (p = 0.056).

CONCLUSIONS

Factors associated with recurrence after resection of localized-type TGCT were larger tumor size and initial treatment with arthroscopy. Relatively low complication rates and good functional outcomes warrant an open approach with complete resection when possible to reduce recurrence rates in high-risk patients.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Soft tissue sarcomas of the upper extremities: Maximizing treatment opportunities and outcomes

Soft tissue sarcomas (STS) are rare tumors; they do not even equate to 1% of all malignant tumor cases. One-fifth of all STS occur in the upper extremities, where epithelioid sarcoma, synovial sarcoma, clear cell sarcoma and malignant fibrohistiocytoma are the most frequent subtypes. Surgical resection is the cornerstone of treatment. However, accomplishment of optimal oncological and functional results of STS of the upper extremities may represent a challenge for hand surgeons, due to the complex anatomy. In several cases, preoperative therapies are needed to facilitate tumor resection and improve the oncological outcome. Oligometastatic disease may also be a challenging scenario as curative strategies can be applied. Radiotherapy and chemotherapy are commonly used for this purpose albeit with conflicting evidence. Novel drug combinations have also been approved in the metastatic setting, further improving the quality of life and survival of eligible patients. Thus, prior to any approach, every case should be individually discussed in sarcoma centers with specialized multidisciplinary tumor boards. The aim of the present review was to gather the multidisciplinary experiences of the available therapeutic strategies for STS of the upper extremities.

Surgical outcomes of patients with diffuse-type tenosynovial giant-cell tumours: an international, retrospective, cohort study

BACKGROUND

Diffuse-type tenosynovial giant-cell tumour is a rare, locally aggressive, and difficult-to-treat soft tissue tumour. Clinical and surgical outcomes depend on multiple factors, including preoperative diagnostic assessment, the localisation and extent of disease, and possibly the choice of treatment modalities by orthopaedic surgeons. We did a retrospective cohort study to characterise global surgical treatment protocols, and assess surgical outcomes, complications, and functional results in patients with diffuse-type tenosynovial giant-cell tumours.

METHODS

In this international, multicentre, retrospective cohort study, we included consecutive patients treated in 31 sarcoma reference centres between Jan 1, 1990, and Dec 31, 2017. Eligible patients were of any age and had histologically proven diffuse-type tenosynovial giant-cell tumour of large joints. Patient data were retrieved from the local databases of participating centres. Patients with localised-type tenosynovial giant-cell tumour were excluded. In the analysis, we only included patients with complete core criteria data regarding admission status, date of treatment, type of treatment at participating centre, and first local recurrence after treatment. We used a non-parametric method to estimate recurrence-free survival at 3, 5, and 10 years after initial surgical resection in a tertiary centre. We used a multivariate Cox regression model to estimate the effect of risk factors. We also present subgroup analyses of disease status at presentation (primary vs recurrent disease) and recurrence-free survival by surgery type (open surgery vs arthroscopic synovectomy), and prespecified risk factors were tested in a univariate and multivariable analyses, with an endpoint of first local recurrence after treatment in a tertiary centre.

FINDINGS

Data collection for these analyses occurred between January, 2016, and May, 2018. We received the records of 1192 patients, of which 966 (81%) were surgically treated and had complete information on core criteria. 445 patients were admitted with therapy-naive disease of the knee and were primarily treated in a tertiary centre. Since patients with wait and see treatment do not have a starting date of treatment, these patients were excluded in the calculation of median follow-up time for all patients. For this calculation we used time of surgery as a starting date. 758 (64%) of 1192 patients had knee involvement and 628 (54%) of 1163 patients with complete data on type of surgery had one-staged open synovectomy. At a median follow-up of 54 months (IQR 27-97), recurrent disease developed in 425 (44%) of all 966 surgically treated cases, and recurrence-free survival was 62% (95% CI 59-65) at 3 years, 55% (51-58) at 5 years, and 40% (35-45) at 10 years. Surgical complications were reported in 105 (12%) of 906 patients who had complete data on surgical complications. Pain improved after surgical treatment in 255 (59%) of 434 patients and swelling improved in 328 (72%) of 453 patients who had complete data.

INTERPRETATION

This study of patients with diffuse-type tenosynovial giant-cell tumour provides a comprehensive and up-to-date disease overview, assessing the clinical profile and management of the disease in multiple specialised referral centres. Surgical treatment of diffuse-type tenosynovial giant cell tumours is not a definitive treatment for every patient because it involves a high risk for local recurrent disease and a relatively high risk for postoperative complications. After surgical treatment in treatment-naive patients, risk factors for recurrent disease in individual patients were not identified in what we believe is the largest cohort to date.

FUNDING

Daiichi Sankyo.

Tenosynovial giant cell tumours of the hand: A multicentre case-control study

Many factors have been proposed to contribute to the risk of recurrent tenosynovial giant cell tumours (TSGCT); however, we remain unable to predict those at risk, which formed the rationale for this multicentre retrospective case-control study of 28 patients with recurrence. We included cases of recurrence in a 1:1 ratio matched for age and sex with controls over 10 years. Using Cox regression, we present hazard ratios (HRs) for recurrence with 95% confidence intervals (CIs). Out of 285 cases, 28 individuals developed recurrence after a median of 2.4 years. Recurrent TSGCT had a higher mitotic count/mm² in the primary tumour (median increase of 3 [IQR 1, 7]). Mitotic count in the primary tumour was associated with the risk of recurrence (adjusted HR 1.1 [95% CI 1.1, 1.2]) meaning that for every additional mitosis, the risk of recurrence increased by 10% per annum. We recommend a prospective cohort study to validate our findings.

Does CSF1 overexpression or rearrangement influence biological behaviour in tenosynovial giant cell tumours of the knee?

Aims

Localised‐ and diffuse‐type tenosynovial giant cell tumours (TGCT) are regarded as different clinical and radiological TGCT types. However, genetically and histopathologically they seem indistinguishable. We aimed to correlate CSF1 expression and CSF1 rearrangement with the biological behaviour of different TGCT‐types with clinical outcome (recurrence).

Methods and results

Along a continuum of extremes, therapy‐naive knee TGCT patients with >3‐year follow‐up, mean age 43 (range = 6–71) years and 56% females were selected. Nine localised (two recurrences), 16 diffuse‐type (nine recurrences) and four synovitis as control were included. Rearrangement of the CSF1 locus was evaluated with split‐apart fluorescence in‐situ hybridisation (FISH) probes. Regions were selected to score after identifying CSF1‐expressing regions, using mRNA ISH with the help of digital correlative microscopy. CSF1 rearrangement was considered positive in samples containing >2 split signals/100 nuclei. Irrespective of TGCT‐subtype, all cases showed CSF1 expression and in 76% CSF1 rearrangement was detected. Quantification of CSF1‐expressing cells was not informative, due to the extensive intratumour heterogeneity. Of the four synovitis cases, two also showed CSF1 expression without CSF1 rearrangement. No correlation between CSF1 expression or rearrangement with clinical subtype and local recurrence was detected. Both localised and diffuse TGCT cases showed a scattered distribution in the tissue of CSF1‐expressing cells.

Conclusion

In diagnosing TGCT,CSF1 mRNA‐ISH, in combination with CSF1 split‐apart FISH using digital correlative microscopy, is an auxiliary diagnostic tool to identify rarely occurring neoplastic cells. This combined approach allowed us to detect CSF1 rearrangement in 76% of the TGCT cases. Neither CSF1 expression nor presence of CSF1 rearrangement could be associated with the difference in biological behaviour of TGCT.

Tenosynovial Giant Cell Tumors in Children: A Similar Entity Compared With Adults

BACKGROUND

Tenosynovial giant cell tumor (TGCT) is a rare, benign, monoarticular entity. Many case-series in adults are described, whereas TGCT is only incidentally reported in children. Therefore, its incidence rate and natural history in children are unknown.

QUESTIONS/PURPOSES

(1) How many cases have been reported of this condition, and what were their characteristics? (2) What is the standardized pediatric incidence rate for TGCT? (3) Is there a clinical difference in TGCT between children and adults? (4) What is the risk of recurrence after open resection in children compared with adults?

METHODS

Data were derived from three sources: (1) a systematic review on TGCT in children, seeking sources published between 1990 and 2016, included 17 heterogeneous, small case-series; (2) the nationwide TGCT incidence study: the Dutch pediatric incidence rate was extracted from this nationwide study by including patients younger than 18 years of age. This registry-based study, in which eligible patients with TGCT were clinically verified, calculated Dutch incidence rates for localized and diffuse-type TGCT in a 5-year timeframe. Standardized pediatric incidence rates were obtained by using the direct method; (3) from our nationwide bone and soft tissue tumor data registry, a clinical data set was derived. Fifty-seven children with histologically proven TGCT of large joints, diagnosed and treated between 1995 and 2015, in all four tertiary sarcoma centers in The Netherlands, were included. These clinically collected data were compared with a retrospective database of 423 adults with TGCT. Chi-square test and independent t-test were used to compare children and adults for TGCT type, sex, localization, symptoms before diagnosis, first treatment, recurrent disease, followup status, duration of symptoms, and time to followup. The Kaplan-Meier method was used to evaluate recurrence-free survival at 2.5 years.

RESULTS

TGCT is seldom reported because only 76 pediatric patients (39 female), 29 localized, 38 diffuse, and nine unknown type, were identified from our systematic review. The standardized pediatric TGCT incidence rate of large joints was 2.42 and 1.09 per million person-years in localized and diffuse types, respectively. From our clinical data set, symptoms both in children and adults were swelling, pain, and limited ROM with a median time before diagnosis of 12 months (range, 1-72 months). With the numbers available, we did not observe differences in presentation between children and adults in terms of sex, symptoms before diagnosis, first treatment, recurrent disease, followup status, or median time to followup. The 2.5-year recurrence-free TGCT survival rate after open resection was not different with the numbers available between children and adults: 85% (95% confidence interval [CI], 67%-100%) versus 89% (95% CI, 83%-96%) in localized, respectively (p = 0.527) and 53% (95% CI, 35%-79%) versus 56% (95% CI, 49%-64%) in diffuse type, respectively (p = 0.691).

CONCLUSIONS

Although the incidence of pediatric TGCT is low, it should be considered in the differential diagnosis in children with chronic monoarticular joint effusions. Recurrent disease after surgical treatment of this orphan disease seems comparable between children and adults. With targeted therapies being developed, future research should define the most effective treatment strategies for this heterogeneous disease.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Severity classification of Tenosynovial Giant Cell Tumours on MR imaging

AIM

Current development of novel systemic agents requires identification and monitoring of extensive Tenosynovial Giant Cell Tumours (TGCT). This study defines TGCT extension on MR imaging to classify severity.

METHODS

In part one, six MR parameters were defined by field-experts to assess disease extension on MR images: type of TGCT, articular involvement, cartilage-covered bone invasion, and involvement of muscular/tendinous tissue, ligaments or neurovascular structures. Inter- and intra-rater agreement were calculated using 118 TGCT MR scans. In part two, the previously defined MR parameters were evaluated in 174 consecutive, not previously used, MR-scans. TGCT severity classification was established based on highest to lowest Hazard Ratios (HR) on first recurrence.

RESULTS

In part one, all MR parameters showed good inter- and intra-rater agreement (Kappa≥0.66). In part two, cartilage-covered bone invasion and neurovascular involvement were rarely appreciated (<13%) and therefore excluded for additional analyses. Univariate analyses for recurrent disease yielded positive associations for type of TGCT HR12.84(95%CI4.60-35.81), articular involvement HR6.00(95%CI2.14-16.80), muscular/tendinous tissue involvement HR3.50(95%CI1.75-7.01) and ligament-involvement HR4.59(95%CI2.23-9.46). With these, a TGCT severity classification was constructed with four distinct severity-stages. Recurrence free survival at 4 years (log rank p < 0.0001) was 94% in mild localized (n56, 1 recurrence), 88% in severe localized (n31, 3 recurrences), 59% in moderate diffuse (n32, 12 recurrences) and 36% in severe diffuse (n55, 33 recurrences).

CONCLUSION

The proposed TGCT severity classification informs physicians and patients on disease extent and risk for recurrence after surgical treatment. Definition of the most severe subgroup attributes to a universal identification of eligible patients for systemic therapy or trials for novel agents.

The Patient Perspective on the Impact of Tenosynovial Giant Cell Tumors on Daily Living: Crowdsourcing Study on Physical Function and Quality of Life

Background

Tenosynovial giant cell tumor (TGCT) is a rare, benign lesion affecting the synovial lining of joints, bursae, and tendon sheaths. It is generally characterized as a locally aggressive and often recurring tumor. A distinction is made between localized- and diffuse-type. The impact of TGCT on daily living is currently ill-described.

Objective

The aim of this crowdsourcing study was to evaluate the impact of TGCT on physical function, daily activities, societal participation (work, sports, and hobbies), and overall quality of life from a patient perspective. The secondary aim was to define risk factors for deteriorated outcome in TGCT.

Methods

Members of the largest known TGCT Facebook community, PVNS is Pants!!, were invited to an e-survey, partially consisting of validated questionnaires, for 6 months. To confirm disease presence and TGCT-type, patients were requested to share histological or radiological proof of TGCT. Unpaired t tests and chi-square tests were used to compare groups with and without proof and to define risk factors for deteriorated outcome.

Results

Three hundred thirty-seven questionnaires, originating from 30 countries, were completed. Median age at diagnosis was 33 (interquartile range [IQR]=25-42) years, majority was female (79.8% [269/337]), diffuse TGCT (70.3% [237/337]), and affected lower extremities (knee 70.9% [239/337] and hip 9.5% [32/337]). In 299 lower-extremity TGCT patients (32.4% [97/299]) with disease confirmation, recurrence rate was 36% and 69.5% in localized and diffuse type, respectively. For both types, pain and swelling decreased after treatment; in contrast, stiffness and range of motion worsened. Patients were limited in their employment (localized 13% [8/61]; diffuse 11.0% [21/191]) and sport-activities (localized 58% [40/69]; diffuse 63.9% [147/230]). Compared with general US population, all patients showed lower Patient-Reported Outcomes Measurements Information System-Physical Function (PROMIS-PF), Short Form-12 (SF-12), and EuroQoL 5 Dimensions 5 Levels (EQ5D-5L) scores, considered clinically relevant, according to estimated minimal important difference (MID). Diffuse versus localized type scored almost 0.5 standard deviation lower for PROMIS-PF (P<.001) and demonstrated a utility score of 5% lower for EQ-5D-5L (P=.03). In localized TGCT, recurrent disease and ≥2 surgeries negatively influenced scores of Visual Analog Scale (VAS)-pain/stiffness, SF-12, and EQ-5D-5L (P<.05). In diffuse type, recurrence resulted in lower score for VAS, PROMIS-PF, SF-12, and EQ-5D-5L (P<.05). In both types, patients with treatment ≤1year had significantly lower SF-12.

Conclusions

TGCT has a major impact on daily living in a relatively young and working population. Patients with diffuse type, recurrent disease, and ≥2 surgeries represent lowest functional and quality of life outcomes. Physicians should be aware that TGCT patients frequently continue to experience declined health-related quality of life and physical function and often remain limited in daily life, even after treatment(s).

Higher incidence rates than previously known in tenosynovial giant cell tumors

Background and purpose - Tenosynovial giant cell tumors (TGCT) are rare, benign tumors, arising in synovial lining of joints, tendon sheaths, or bursae. 2 types are distinguished: localized, either digits or extremity, and diffuse lesions. Current TGCT incidence is based on 1 single US-county study in 1980, with an incidence of 9 and 2 per million person-years in localized (including digits) and diffuse TGCT, respectively. We aim to determine nationwide and worldwide incidence rates (IR) in TGCT affecting digits, localized-extremity TGCT and diffuse-type TGCT. Material and methods - Over a 5-year period, the Dutch Pathology Registry (PALGA) identified 4,503 pathology reports on TGCT. Reports affecting digits were solely used for IR calculations. Reports affecting extremities were clinically evaluated. Dutch IRs were converted to world population IRs. Results - 2,815 (68%) digits, 933 (23%) localized-extremity and 390 (9%) diffuse-type TGCT were identified. Dutch IR in digits, localized-extremity, and diffuse-type TGCT was 34, 11 and 5 per million person-years, respectively. All 3 groups showed a female predilection and highest number of new cases in age category 40-59 years. The knee joint was most often affected: localized-extremity (46%) and diffuse-type (64%) TGCT, mostly treated with open resection: localized (65%) and diffuse (49%). Reoperation rate due to local recurrence for localized-extremity was 9%, and diffuse TGCT 23%. Interpretation - This first nationwide study and detailed analyses of IRs in TGCT estimated a worldwide IR in digits, localized-extremity and diffuse TGCT of 29, 10, and 4 per million person-years, respectively. Recurrence rate in diffuse type is 2.6 times higher, compared with localized extremity. TGCT is still considered a rare disease; however, it is more common than previously understood.

Giant Cell Tumor of the Patellar Tendon Sheath: A Rare Case of Anterior Knee Pain

Giant cell tumor of the tendon sheath (GCTTS) is a benign, proliferative lesion of the synovium of the joint, the bursa, and the tendon sheath. We report a case of intra-articular, localized GCTTS arising from the patellar tendon, which is a rare cause of anterior knee pain. The diagnosis may be delayed due to non-specific symptoms and normal plain radiographic findings. Magnetic resonance imaging (MRI) is diagnostic to detect the lesion, but several other clinical entities and lesions should be evaluated in the differential diagnosis. The treatment of choice is a total excision of the lesion without leaving residual tumor tissue, in order to reduce the risk of recurrence. We present a patient with GCTTS of the patellar tendon and discuss its clinical and radiographic characteristics, differential diagnosis, pathology, and treatment.

Limb Amputation after Multiple Treatments of Tenosynovial Giant Cell Tumour: Series of 4 Dutch Cases

In Tenosynovial Giant Cell Tumours (TGCT), previously named Pigmented Villonodular Synovitis (PVNS), a distinction is made between a single nodule (localized-type) and multiple nodules (diffuse-type). Diffuse-type is considered locally aggressive. Onset and extermination of this orphan disease remain unclear. Surgical resection is the most commonly performed treatment. Unfortunately, recurrences often occur (up to 92%), necessitating reoperations and adjuvant treatments. Once all treatments fail or if severe complications occur, limb amputation may become unavoidable. We describe four cases of above-knee amputation after TGCT diagnosis.

Pigmented villonodular synovitis: a crowdsourcing study of two hundred and seventy two patients

PURPOSE

We aimed to ascertain the feasibility of crowdsourcing via Facebook for medical research purposes; by investigating surgical, oncological and functional outcome and quality-of-life (QOL) in patients with pigmented villonodular synovitis (PVNS) enrolled in a Facebook community (1112 members).

METHODS

Patients completed online open surveys on demographics, surgery and clinical outcomes (group 1); and patient-reported outcome measures (PROMs) including knee-injury osteoarthritis outcome score (KOOS), hip-disability osteoarthritis outcome score (HOOS), Toronto extremity salvage score (TESS) and SF-36 (group 2). Mean follow-up was 70 months (12-374). Consistency checks were performed with Cohen's kappa statistic for intra-rater agreement.

RESULTS

The first survey was completed by 272 patients (group 1) and 72 patients completed the second (group 2). In group 1, recurrence-rate was 58 % (69/118) after arthroscopic, 36 % (35/97) after open and 50 % (5/10) after combined synovectomy (p = 0.003). In group 2, recurrence-rate was 67 % (26/39) after arthroscopic and 51 % (17/33) after open synovectomy (p = 0.19). Recurrence-risk was increased for diffuse disease (OR = 16; 95%CI = 3.2-85; p < 0.001). Mean function and QOL did not differ after arthroscopic or open synovectomy: KOOS 49 vs. 58 (p = 0.24), HOOS 62 vs. 53 (p = 0.56), TESS 78 vs. 82 (p = 0.86), SF-36 61 vs. 66 (p = 0.41). Cohen's kappa statistic for intra-rater agreement was good to outstanding (κ = 0.68-0.95; p < 0.001).

CONCLUSION

Local recurrence-risk was higher for diffuse-type disease and arthroscopic synovectomy. Functional outcome and QOL were comparable for both types of surgery. Gathering data via crowdsourcing seems a promising and innovative way of evaluating rare diseases including PVNS.

Giant Cell Tumor of the Patella Tendon Sheath Presenting as a Painful Locked Knee

Patient: Male, 26

Final Diagnosis: Giant cell tumor of the patella tendon seath

Symptoms: Efusion • locking knee • pain

Medication: None

Clinical Procedure: Arthroscopy and open resection of the tumor

Specialty: Orthopedics and Traumatology

Functional outcome and quality of life after the surgical treatment for diffuse-type giant-cell tumour around the knee

We retrospectively reviewed 30 patients with a diffuse-type giant-cell tumour (Dt-GCT) (previously known as pigmented villonodular synovitis) around the knee in order to assess the influence of the type of surgery on the functional outcome and quality of life (QOL). Between 1980 and 2001, 15 of these tumours had been treated primarily at our tertiary referral centre and 15 had been referred from elsewhere with recurrent lesions.

The mean follow-up was 64 months (24 to 393). Functional outcome and QOL were assessed with range of movement and the Knee injury and Osteoarthritis Outcome Score (KOOS), the Musculoskeletal Tumour Society (MSTS) score, the Toronto Extremity Salvage Score (TESS) and the SF-36 questionnaire. There was recurrence in four of 14 patients treated initially by open synovectomy. Local control was achieved after a second operation in 13 of 14 (93%). Recurrence occurred in 15 of 16 patients treated initially by arthroscopic synovectomy. These patients underwent a mean of 1.8 arthroscopies (one to eight) before open synovectomy. This achieved local control in 8 of 15 (53%) after the first synovectomy and in 12 of 15 (80%) after two. The functional outcome and QOL of patients who had undergone primary arthroscopic synovectomy and its attendant subsequent surgical procedures were compared with those who had had a primary open synovectomy using the following measures: range of movement (114º versus 127º; p = 0.03); KOOS (48 versus 71; p = 0.003); MSTS (19 versus 24; p = 0.02); TESS (75 versus 86; p = 0.03); and SF-36 (62 versus 80; p = 0.01).

Those who had undergone open synovectomy needed fewer subsequent operations. Most patients who had been referred with a recurrence had undergone an initial arthroscopic synovectomy followed by multiple further synovectomies. At the final follow-up of eight years (2 to 32), these patients had impaired function and QOL compared with those who had undergone open synovectomy initially.

We conclude that the natural history of Dt-GCT in patients who are treated by arthroscopic synovectomy has an unfavourable outcome, and that primary open synovectomy should be undertaken to prevent recurrence or residual disease.

Cite this article: Bone Joint J 2014; 96-B:1111–18.

Update on the surgical management of temporomandibular joint-centered tendon sheath giant cell tumor with intradural extension: introducing a cost-effective method in using temporal bone for skull base reconstruction in preventing brain hernia

Tendon sheath giant cell tumor is an idiopathic proliferative and destructive disease of the synovium. It is rare and tends to arise in large joints, for example, knee and ankle, but it can also arise in temporomandibular joints (TMJs). Because of its destructive nature, immediate treatment upon diagnosis is recommended. Radical resection proved to be an excellent choice for superior local control. However, the unfavorable anatomic location of TMJ and infratemporal fossa tumor with intradural extension make such a resection impractical. Hereby, we reported a case of resection of a TMJ tendon sheath giant cell tumor with intradural extension using a transcranial approach. This involves a complex radical resection with subsequent reconstruction. Transposition of temporal bone flap is a novel state-of-the-art technique in reconstructing the middle fossa floor defect by providing a three-dimensional rigid architecture to support the brain. Temporal bone flap is a reliable plug for rigid support in preventing brain hernia and cerebrospinal fluid leak. Despite its complexity, this cost-effective technique is relatively straightforward to learn and is applicable across all socioeconomic groups.