Biological sample collection to advance research and treatment: a Fight Osteosarcoma Through European Research (FOSTER) and Euro Ewing Consortium (EEC) statement.

Osteosarcoma and Ewing sarcoma are bone tumours mostly diagnosed in children, adolescents and young adults. Despite multi-modal therapy, morbidity is high and survival rates remain low, especially in the metastatic disease setting. Trials investigating targeted therapies and immunotherapies have not been ground-breaking. Better understanding of biological subgroups, the role of the tumour immune microenvironment, factors that promote metastasis and clinical biomarkers of prognosis and drug response are required to make progress. A prerequisite to achieve desired success is a thorough, systematic and clinically linked biological analysis of patient samples but disease rarity and tissue processing challenges such as logistics and infrastructure have contributed to a lack of relevant samples for clinical care and research. There is a need for a Europe-wide framework to be implemented for the adequate and minimal sampling, processing, storage and analysis of patient samples. Two international panels of scientists, clinicians and patient and parent advocates have formed the Fight Osteosarcoma Through European Research (FOSTER) consortium and the Euro Ewing Consortium (EEC). The consortia shared their expertise and institutional practices to formulate new guidelines. We report new reference standards for adequate and minimally required sampling (time points, diagnostic samples, liquid biopsy tubes), handling and biobanking to enable advanced biological studies in bone sarcoma. We describe standards for analysis and annotation to drive collaboration and data harmonisation with practical, legal and ethical considerations. This position paper provides comprehensive guidelines that should become the new standards of care that will accelerate scientific progress, promote collaboration and improve outcomes.

Health-related quality of life and associated risk factors in patients with Multiple Osteochondromas: a cross-sectional study.

PURPOSE: To evaluate the health-related quality of life and associated risk factors for Multiple Osteochondromas patients. METHODS: A cross-sectional, observational study was conducted from May to December 2022 during the routine visit to the referral center for rare skeletal disorders. All patients with Multiple Osteochondromas aged ≥ 3 years were included. EuroQol 5-dimension questionnaires, and demographic, clinical, and surgical history data were collected. Descriptive statistics, Fisher's exact test, One-sample t-test, Spearman's correlation, and multiple linear and logistic regression were performed to analyze the data. Results are reported following STROBE guidelines. RESULTS: A total of 128 patients were included in the study, with a mean age of 14 [SD, 10] years. The mean EQ-5D Index Value was 0.863 [SD, 0.200] and the EQ-VAS was 84 [SD, 19] with a positive correlation between two scores [r = 0.541, p < 0.001]. Patients frequently referred problems in pain/discomfort [78.8%], anxiety/depression [50%], and usual activities [38.8%] dimensions. Increasing age was the common risk factor for health-related quality of life [p < 0.000], as well as Index Value and VAS scores were significantly lower in surgical patients [p = 0.001 and p < 0.001, respectively]. CONCLUSION: Increasing age and surgical procedures were found highly associated with reduced health-related quality of life in Multiple Osteochondromas patients. Our findings provide relevant information to support the establishment of patient-centered healthcare pathways and pave the way for further research into medical and non-medical therapeutic strategies for these patients.

Active surveillance of diffuse-type tenosynovial giant cell tumors: A retrospective, multicenter cohort study.

BACKGROUND: Diffuse-type tenosynovial giant cell tumor (D-TGCT) is a mono-articular, soft-tissue tumor. Although it can behave locally aggressively, D-TGCT is a non-malignant disease. This is the first study describing the natural course of D-TGCT and evaluating active surveillance as possible treatment strategy. METHODS: This retrospective, multicenter study included therapy naïve patients with D-TGCT from eight sarcoma centers worldwide between 2000 and 2019. Patients initially managed by active surveillance following their first consultation were eligible. Data regarding the radiological and clinical course and subsequent treatments were collected. RESULTS: Sixty-one patients with primary D-TGCT were initially managed by active surveillance. Fifty-nine patients had an MRI performed around first consultation: D-TGCT was located intra-articular in most patients (n = 56; 95 %) and extra-articular in 14 cases (24 %). At baseline, osteoarthritis was observed in 13 patients (22 %) on MRI. Most of the patients' reported symptoms: pain (n = 43; 70 %), swelling (n = 33; 54 %). Eight patients (13 %) were asymptomatic. Follow-up data were available for 58 patients; the median follow-up was 28 months. Twenty-one patients (36 %) had radiological progression after 21 months (median). Eight of 45 patients (18 %) without osteoarthritis at baseline developed osteoarthritis during follow-up. Thirty-seven patients (64 %) did not clinically deteriorate during follow-up. Finally, eighteen patients (31 %) required a subsequent treatment. CONCLUSION: Active surveillance can be considered adequate for selected therapy naïve D-TGCT patients. Although follow-up data was limited, almost two-thirds of the patients remained progression-free, and 69 % did not need treatment during the follow-up period. However, one-fifth of patients developed secondary osteoarthritis. Prospective studies on active surveillance are warranted.

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).

Best clinical management of tenosynovial giant cell tumour (TGCT): A consensus paper from the community of experts.

Tenosynovial giant cell tumour (TGCT) is a rare, locally aggressive, mesenchymal tumor arising from the joints, bursa and tendon sheaths. TGCT comprises a nodular- and a diffuse-type, with the former exhibiting mostly indolent course and the latter a locally aggressive behavior. Although usually not life-threatening, TGCT may cause chronic pain and adversely impact function and quality of life (QoL). CSFR1 inhibitors are effective with benefit on symptoms and QoL but are not available in most countries. The degree of uncertainty in selecting the most appropriate therapy and the lack of guidelines on the clinical management of TGCT make the adoption of new treatments inconsistent across the world, with suboptimal outcomes for patients. A global consensus meeting was organized in June 2022, involving experts from several disciplines and patient representatives from SPAGN to define the best evidence-based practice for the optimal approach to TGCT and generate the recommendations presented herein.

A prospective real-world study of the diffuse-type tenosynovial giant cell tumor patient journey: A 2-year observational analysis.

BACKGROUND AND OBJECTIVES: Diffuse-tenosynovial giant cell tumor (D-TGCT) is a rare, locally aggressive, typically benign neoplasm affecting mainly large joints, representing a wide clinical spectrum. We provide a picture of the treatment journey of D-TGCT patients as a 2-year observational follow-up. METHODS: The TGCT Observational Platform Project registry was a multinational, multicenter, prospective observational study at tertiary sarcoma centers spanning seven European countries and two US sites. Histologically confirmed D-TGCT patients were categorized as either those who remained on initial treatment strategy (determined at baseline visit) or those who changed treatment strategy with specific changes documented (e.g., systemic treatment to surgery) at the 1-year and/or 2-year follow-up visits. RESULTS: A total of 176 patients were assessed, mean diagnosis age was 38.4 (SD ± 14.6) years; most patients had a knee tumor (120/176, 68.2%). For the 2-year observation period, most patients (75.5%) remained on the baseline treatment strategy throughout, 54/79 patients (68.4%) remained no treatment, 30/45 patients (66.7%) remained systemic treatment, 39/39 patients (100%) remained surgery. Those who changed treatment strategy utilized multimodal treatment options. CONCLUSIONS: This is the first prospectively collected analysis to describe D-TGCT patient treatments over an extended follow-up and demonstrates the need for multidisciplinary teams to determine an optimal treatment strategy.

Treatment updates on tenosynovial giant cell tumor.

PURPOSE OF REVIEW: Diffuse-type tenosynovial giant cell tumor (dt-TGCT) is a benign clonal neoplastic proliferation arising from the synovium. Patients are often symptomatic, require multiple surgical procedures during their lifetime, and have reduced quality of life (QoL). Surgery is the main treatment with relapse rates ranging from 14 to 55%. The treatment strategy for patients with dt-TGCT is evolving. The purpose of this review is to describe current treatment options, and to highlight recent developments in the knowledge of the molecular pathogenesis of dt-TGCT as well as related therapeutic implications. RECENT FINDINGS: TGCT cells overexpress colony-stimulating factor 1 (CSF1), resulting in recruitment of CSF1 receptor (CSF1R)-bearing macrophages that are polyclonal and make up the bulk of the tumor, has led to clinical trials with CSF1R inhibitors. These inhibitors include small molecules such as pexidatinib, imatinib, nilotinib, DCC-3014 (vimseltinib), and the monoclonal antibody RG7155 (emactuzumab). SUMMARY: In conclusion, D-TGCT impairs patients' QoL. The evidence that the pathogenetic loop of D-TGCT can be inhibited has changed the therapeutic armamentarium for this condition. Clinical trials of agents that target CSF1R are currently ongoing. All this new evidence should be taken into consideration within multidisciplinary management.

Phase 2 study for nonmetastatic extremity high-grade osteosarcoma in pediatric and adolescent and young adult patients with a risk-adapted strategy based on ABCB1/P-glycoprotein expression: An Italian Sarcoma Group trial (ISG/OS-2).

BACKGROUND: According to retrospective osteosarcoma series, ABCB1/P-glycoprotein (Pgp) overexpression predicts for poor outcomes. A prospective trial to assess a risk-adapted treatment strategy using mifamurtide in Pgp+ patients was performed. METHODS: This was a phase 2, multicenter, uncontrolled trial including patients 40 years old or younger with nonmetastatic extremity high-grade osteosarcoma stratified according to Pgp expression. All patients received high-dose methotrexate, doxorubicin, and cisplatin (MAP) preoperatively. In Pgp+ patients, mifamurtide was added postoperatively and combined with MAP for a good histologic response (necrosis ≥ 90%; good responders [GRs]) or with high-dose ifosfamide (HDIFO) at 3 g/m2 /d on days 1 to 5 for a histologic response < 90% (poor responders [PRs]). Pgp- patients received MAP postoperatively. After an amendment, the cumulative dose of methotrexate was increased from 60 to 120 g/m2 (from 5 to 10 courses). The primary end point was event-free survival (EFS). A postamendment analysis was performed. RESULTS: In all, 279 patients were recruited, and 194 were included in the postamendment analysis: 70 (36%) were Pgp-, and 124 (64%) were Pgp+. The median follow-up was 51 months. For Pgp+ patients, 5-year EFS after definitive surgery (null hypothesis, 40%) was 69.8% (90% confidence interval [CI], 62.2%-76.2%): 59.8% in PRs and 83.7% in GRs. For Pgp- patients, the 5-year EFS rate was 66.4% (90% CI, 55.6%-75.1%). CONCLUSIONS: This study showed that adjuvant mifamurtide, combined with HDIFO for a poor response to induction chemotherapy, could improve EFS in Pgp+ patients. Overall, the outcomes compared favorably with previous series. Mifamurtide and HDIFO as salvage chemotherapy are worth further study.

The Rizzoli Multiple Osteochondromas Classification revised: describing the phenotype to improve clinical practice.

Multiple osteochondromas (MO) is a rare disorder, characterized by benign osteocartilaginous tumors (osteochondromas), arising from the perichondrium of bones. The osteochondromas increase during growth, frequently causing deformities and limitations. Our study aims to analyze the data captured by the Registry of Multiple Osteochondromas, to refine Istituto Ortopedico Rizzoli (IOR) Classification, providing a representative picture of the phenotypic manifestations throughout the lifespan. We conducted a single-institution cross-sectional study. Patients were categorized according to IOR Classification, which identifies three patients' classes on the presence/absence of deformities and/or limitations. The present dataset was compared with our previously published data, to refine the classification. Nine hundred sixty-eight patients were included: 243 children (<10 years), 136 adolescents (10-15 years), and 589 adults. Of the entire population, half patients presented at least one deformity, and one quarter reported at least one limitation. Compared with our previous study, the amount of children was more than doubled and the percentage of mild/moderate cases was notably increased, giving a better disease overview throughout the lifespan and suggesting a different cut-off for dividing Class II in subclasses. We confirmed that MO is characterized by phenotypic heterogeneity, suggesting that an early classification of the disease may offer a useful tool to follow disease pattern and evolution, to support clinical practice, and to propose timely interventions.

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 .

Long-term outcomes of pexidartinib in tenosynovial giant cell tumors.

BACKGROUND: The objective of this study was to report on the long-term effects of pexidartinib on tenosynovial giant cell tumor (TGCT). METHODS: This was a pooled analysis encompassing 3 pexidartinib-treated TGCT cohorts: 1) a phase 1 extension study (NCT01004861; 1000 mg/d; n = 39), 2) ENLIVEN patients randomized to pexidartinib (1000 mg/d for 2 weeks and then 800 mg/d; n = 61), and 3) ENLIVEN crossover patients (NCT02371369; 800 mg/d; n = 30). Eligible patients were 18 years old or older and had a histologically confirmed TGCT that was unresectable and symptomatic. Efficacy endpoints included the best overall response (complete or partial response) and the duration of response (DOR) by the Response Evaluation Criteria in Solid Tumors (RECIST) and the tumor volume score (TVS). The safety assessment included the frequency of treatment-emergent adverse events (TEAEs) and hepatic laboratory abnormalities (aminotransferase elevations and mixed/cholestatic hepatotoxicity). The data cutoff was May 31, 2019. RESULTS: One hundred thirty patients with TGCT received pexidartinib (median treatment duration, 19 months; range, 1 to 76+ months); 54 (42%) remained on treatment at the end of the analysis (26 months after initial data cut of March 2017). The RECIST overall response rate (ORR) was 60%; the TVS ORR was 65%. The median times to response were 3.4 (RECIST) and 2.8 months (TVS), with 48 of the responding patients (62%) achieving a RECIST partial response by 6 months and with 72 (92%) doing so by 18 months. The median DOR was reached for TVS (46.8 months). Reported TEAEs were mostly low-grade, with hair color changes being most frequent (75%). Most liver abnormalities (92%) were aminotransferase elevations; 4 patients (3%) experienced mixed/cholestatic hepatotoxicity (all within the first 2 months of treatment), which was reversible in all cases (recovery spanned 1-7 months). CONCLUSIONS: This study demonstrates the prolonged efficacy and tolerability of long-term pexidartinib treatment for TGCT.

Rare Primary Malignant Bone Sarcomas.

Rare primary malignant bone sarcomas (RPMBS), other than osteosarcoma, chondrosarcoma, chordoma, and Ewing sarcoma, account for about 5-10% of primary bone tumors and represent a major diagnostic challenge. These tumors include spindle cell and round cell sarcoma entities, hemangiopericytoma-like and vascular tumors. Additionally, several histotypes, traditionally described in the soft tissues, such as myxofibrosarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor of bone, have been reported in patients with primary bone tumors. While wide surgical resection is the mainstay of local treatment, systemic therapy of these rare entities is controversial. Patients with undifferentiated spindle cell or pleomorphic high-grade tumors of bone, are usually treated with osteosarcoma-like chemotherapy, while patients with round cell and undifferentiated round cell tumors (URCTs), may respond to sarcoma treatment regimens for Ewing sarcoma patients. Studies on analogies and differences among these ultra-rare tumors have seldom been reported. This review describes relevance, clinical aspects, diagnostic procedures, staging, treatment recommendations, and current research in this composite tumor group.

Incomplete resection increases the risk of local recurrence and negatively affects functional outcome in patients with tenosynovial giant cell tumor of the hindfoot.

BACKGROUND: Diffuse tenosynovial giant cell tumors (TGCT) are more likely to occur in the hindfoot and tend to recur after surgical excision. We performed a pooled analysis of hindfoot TGCT cases to identify factors associated with local recurrence and functional outcomes. METHODS: We retrospectively reviewed medical records of 33 patients diagnosed with TGCT (15, localized cases; 18 diffused cases) of the hindfoot between 1998 and 2017. Median follow-up was 32 months. Multivariable Cox proportional hazards regression analysis was conducted to estimate the hazard ratios for risk factors for local failure. Generalized linear regression models were used to assess whether resection status, tumor size, tumor type or bone involvement correlated with the Musculoskeletal Tumor Society (MSTS) score. RESULTS: Local failure was reported in 30% (10/33) patients. Multivariable analysis showed that macroscopically incomplete resection was the only independent prognostic factor for poor local failure-free survival (P=.001). Incomplete resection significantly decreased MSTS score and negatively affected functional outcome (P=.047). CONCLUSIONS: Incomplete resection increases the risk of local recurrence and negatively affects functional outcome in patients with TGCT of the hindfoot.

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.

Prevalence and Clinical Features of Mazabraud Syndrome: A Multicenter European Study.

BACKGROUND: Mazabraud syndrome is a rare disorder, characterized by the presence of fibrous dysplasia (FD) with associated intramuscular myxomas. Data are scarce on the prevalence, clinical features, and natural history of this disorder and outcomes. In this multicenter study, we evaluated a series of patients from 6 European centers. METHODS: All centers affiliated with the European Musculo-Skeletal Oncology Society (EMSOS) were invited to include data on all patients with Mazabraud syndrome who were seen between 1980 and 2015. The study investigated the prevalence of Mazabraud syndrome, the type, severity, and localization of FD lesions in relation to myxomas, the histopathology of myxomas, and results of GNAS-mutation analysis, when available. RESULTS: Thirty-two patients (22 female) from 6 centers were included. The prevalence of Mazabraud syndrome was 2.2% in the combined cohort of 1,446 patients with FD, and the syndrome was diagnosed at a mean of 10.1 years after diagnosis of FD. The myxomas were predominantly localized in the upper leg. Excision was performed in 20 patients, recurrence occurred in 6 of these patients (30%) at a median of 8.5 years (range, 1.9 to 16.0 years), and revision surgery was necessary in 5 (25%). High cellularity of myxomas was associated with recurrence (p < 0.05). A GNAS mutation was identified in the myxoma tissue of 5 (83%) of 6 patients with GNAS-mutation analysis. CONCLUSIONS: This study is the first, to our knowledge, to provide data on the prevalence of Mazabraud syndrome in a relatively large cohort. Although the outcomes of surgical resection were good, a quarter of the patients required revision surgery despite clear resection margins. High cellularity of myxomas was associated with recurrence. GNAS mutations were identified in 83% (5 of 6), emphasizing the shared origin of FD and myxomas. Our data show that patients with FD who have disproportionate complaints, irrespective of FD type, extent, or severity, should be investigated for the possible presence of myxomas. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Treatment of chronic osteomyelitis with antibiotic-loaded bone void filler systems: an experience with hydroxyapatites calcium-sulfate biomaterials.

This is a retrospective study that aims to quantify the problem of chronic osteomyelitis in one of the largest Italian orthopedic centers. Furthermore this study is focused on evaluation of efficacy of bone void filler systems with particular attention to a subgroup of patients treated with PerOssal®. Ninety-seven patients were included in this study between 2008 and 2013 with a minimum follow up of 24 months. A subgroup of 52 patients was treated with curettage plus PerOssal®, another group was treated with curettage only or curettage with other bone void filler systems. Overall we obtained a cure rate of 80,4%, whereas 19,6% had recurrent infection. Looking at the subgroup treated with PerOssal® we found a healing rate of 86,5%, which was significantly higher compared to the other groups. Of the patients with recurrence of infection, those treated with PerOssal® recurred 106 days later than the other patients.

Diffuse-type tenosynovial giant cell tumour: Current treatment concepts and future perspectives.

At present, the optimal treatment strategy in patients with diffuse-type tenosynovial giant cell tumour (D-TGCT) is unclear. The purpose of this review was to describe current treatment options, and to highlight recent developments in the knowledge of the molecular pathogenesis of D-TGCT as well as related therapeutic implications. Epidemiology, clinical features, and the pathogenesis of D-TGCT and the most widely used treatment modalities are described. D-TGCT is a benign clonal neoplastic proliferation arising from the synovium. Patients are often symptomatic and require multiple surgical procedures during their lifetime. Currently, surgery is the main treatment for patients with D-TGCT, with relapse rates ranging from 14% to 55%. Radiosynovectomy and external beam radiotherapy have been used in combination with surgical excision or as single modalities. The finding that D-TGCT cells overexpress colony-stimulating factor 1 (CSF1), resulting in recruitment of CSF1 receptor (CSF1R)-bearing macrophages that are polyclonal and make up the bulk of the tumour, has led to clinical trials with CSF1R inhibitors. These inhibitors include small molecules such as imatinib, nilotinib, PLX3397, and the monoclonal antibody RG7155. In conclusion, D-TGCT impairs patients' quality of life significantly. The evidence that the pathogenetic loop of D-TGCT can be inhibited could potentially change the therapeutic armamentarium for this condition. Clinical trials of agents that target D-TGCT are currently ongoing. In the meantime, international registries should be activated in order to provide useful information on this relatively rare tumour.

Are Complications Associated With the Repiphysis(®) Expandable Distal Femoral Prosthesis Acceptable for Its Continued Use?

BACKGROUND: Reconstruction of the distal femur after resection for malignant bone tumors in skeletally immature children is challenging. The use of megaprostheses has become increasingly popular in this patient group since the introduction of custom-made, expandable devices that do not require surgery for lengthening, such as the Repiphysis(®) Limb Salvage System. Early reports on the device were positive but more recently, a high complication rate and associated bone loss have been reported. QUESTIONS/PURPOSES: We asked: (1) what are the clinical outcomes using the Musculoskeletal Tumor Society (MSTS) scoring system after 5-year minimum followup in patients treated with this prosthesis at one center; (2) what are the problems and complications associated with the lengthening procedures of this implant; and (3) what are the specific concerns associated with revision of this implant? METHODS: At our institute, between 2002 and 2007, the Repiphysis(®) expandable prosthesis was implanted in 15 children (mean age, 8 years; range, 6-11 years) after distal femoral resection for malignant bone tumors. During this time, the general indication for use of this implant was resection of the distal femur for localized malignant bone tumors in pediatric patients. Alternative techniques used for this indication were modular prosthetic reconstruction, massive (osteoarticular or intercalary) allograft reconstruction, or rotationplasty. Age and tumor extension were the main factors to decide on the surgical indication. Of the 15 patients who had this prosthesis implanted during reconstruction surgery, five died with the implant in situ or underwent amputation before 5 years followup and the remaining 10 were evaluated at a minimum of 5 years (mean, 104 months; range, 78-140 months). No patients were lost to followup. These 10 patients were long-term survivors and underwent the lengthening program. They were included in our study analysis. The first seven lengthening procedures were attempted in an outpatient setting; however, owing to pain and burning sensations experienced by the patients, the procedures failed to achieve the desired lengthening. Therefore, other procedures were performed with the patients under general anesthesia. We reviewed clinical data at index surgery for all 15 patients. We further analyzed the lengthening procedures, implant survival, radiographic and functional results, for the 10 long-term survivors. Functional results were assessed according to the MSTS scoring system. Complications were classified according to the International Society of Limb Salvage (ISOLS) classification system. RESULTS: Nine of the 10 survivors underwent revision of the implant for mechanical failure. They had a mean MSTS score of 64% (range, 47%-87%) before revision surgery. At final followup the 10 long-term surviving patients had an average MSTS score of 81% (range, 53%-97%). In total, we obtained an average lengthening of 39 mm per patient (range, 17-67 mm). Exact expansion of the implant was unpredictable and difficult to control. Nine of 10 of the long-term surviving patients underwent revision surgery of the prosthesis-eight for implant breakage and one for stem loosening. At revision surgery, six patients had another type of expandable prosthesis implanted and three had an adult-type megaprosthesis implanted. In five cases, segmental bone grafts were used during revision surgery to compensate for loss of bone stock. CONCLUSIONS: We could not comfortably expand the Repiphysis(®) prosthesis in an outpatient setting because of pain experienced by the patients during the lengthening procedures. Furthermore, use of the prosthesis was associated with frequent failures related to implant breakage and stem loosening. Revisions of these procedures were complex and difficult. We no longer use this prosthesis and caution others against the use of this particular prosthesis design. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Tenosynovial giant cell tumour/pigmented villonodular synovitis: outcome of 294 patients before the era of kinase inhibitors.

BACKGROUND: Tenosynovial giant cell tumour/pigmented villonodular synovitis (TGCT/PVNS) is a benign neoplasm of synovium and tendon sheath. We conducted a retrospective pooled analysis in three major referral centers. METHODS: Patients treated between 1998 and 2008 were examined. Only patients presenting with primary disease or first relapse were included. 5-year local failure free survival (5-year-LFFS) was analysed. RESULTS: 294 patients were included: 254 with new diagnosis and 40 in 1st local recurrence (171 F/123 M; median age: 36 years; tumour size ⩽2 cm in 27% of patients, >2 to ⩽5 cm in 41%, and >5 cm in 32%). A diffuse pattern was reported in 69%, localised in 31%. No metastases were documented. Local failure (LF) was reported in 28% of patients: 36% in diffuse pattern, 14% in localised (p = 0.002); median time to LF: 16 months. With a median follow-up of 4.4 years, 5-year-LFFS was 66%, with multiple (up to five) local recurrences in 40% of relapsed patients. Size <2 cm, macroscopically complete resection, female gender and new diagnosis were associated with a better local control. After multivariate analysis, a previous relapse was independently associated with local failure. CONCLUSIONS: This study underlines the propensity of TGCT/PVNS to multiple local recurrences. In absence of clinical factors, biological studies are needed to identify prognostic factors of local failure. After a first local recurrence, surgery does not seem to have a curative potential. In these high risk patients, studies addressing the role of target therapies are needed.