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Purpose: Recurrent diffuse-type tenosynovial giant cell tumor: Clinical presentation, Diagnosis, and Management. Background: Tenosynovial giant cell tumor (TGCT), is a neoplasm arising from synovial joints, bursae, or tendon sheaths. The initial clinical symptoms are vague and non-diagnostic. Patients may present with non-specific complaints such as subtle joint discomfort or pain. As the lesion progresses, the joint range of motion will become limited resulting in swelling, effusion, stiffness, and hemarthrosis. According to the World Health Organization (WHO) classification, TGCTs are divided into two main subtypes based on their growth pattern: localized or diffuse. Diffuse-type TGCTs tend to be more aggressive. Case presentation: An 82-year-old female presented with right facial swelling and discomfort. MRI showed a large mass centered in the right temporomandibular joint (TMJ) with erosive osseous changes at the skull base. Past medical history was significant for surgical resection of TGCT of the TMJ, 5 years earlier. The patient was subsequently seen by oral and maxillofacial surgery and neurosurgery and underwent a surgical resection. Histologic examination was consistent with a recurrent diffuse-type TGCT with chondroid metaplasia. Discussion: The role of CSF1 protein over-expression in various synovial pathologies. [ABSTRACT FROM AUTHOR]

Introduction: Tenosynovial giant cell tumors (TGCTs) are locally aggressive mesenchymal neoplasms that often occur in younger patients and cause long-term disability. Surgical management remains the standard of care, but with high risks of surgical morbidity, systemic treatment options are important to consider, particularly in diffuse disease. Improved understanding of the molecular pathogenesis of TGCTs has led to exciting developments in this arena. Areas covered: This review aims to provide historical context for systemic treatments for patients with TGCTs with a focus on the diffuse subtype (DT-TGCT) while exploring the more recently available treatments in depth. Current literature on TGCTs and therapy was reviewed and summarized by a comprehensive search of MEDLINE (1/1/1989–11/30/2024). We also suggest directions for future investigation in the systemic treatment space for TGCT with a goal to alleviate symptoms and improve quality of life while minimizing treatment-related toxicity. Expert opinion: Advances in the understanding of the molecular pathogenesis of TGCT has led to systemic therapies targeting the CSF1 receptor (CSF1R), including the first FDA approval in this space of pexidartinib. These developments provide the foundation for further investigation into additional treatments, optimal sequencing, and duration of therapies for patients with symptoms and reduced functionality secondary to TGCT. [ABSTRACT FROM AUTHOR]

Background: Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive tumor of the joints, bursa, and tendon sheath that can cause considerable pain and substantial morbidity. Although surgery is the primary treatment for patients with TGCT, surgical resection is associated with high rates of recurrence, particularly for patients with diffuse TGCT. Pexidartinib, a colony-stimulating factor 1 receptor inhibitor, is approved by the US Food and Drug Administration for the treatment of adult patients with symptomatic TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Case Description: A 32-year-old man presented with intra-articular diffuse TGCT with pain and received noncurative treatment for 5 years (2014–2019). In 2019, the patient was found to have extensive disease accompanied by pain and limited range of motion. The patient's case was presented to a sarcoma multidisciplinary tumor board, who determined that surgery would cause significant morbidity and macroscopic residual tumor. As a result of the extent of disease, young age, and otherwise good health, treatment with pexidartinib was started through a compassionate use program at 800 mg/day. After dose reductions to pexidartinib at 400 mg/day and then 200 mg/day as a result of creatine phosphokinase elevations, the patient achieved a complete response after 2 years of treatment; pain was reduced and mobility was restored. The patient reported no side effects related to pexidartinib treatment. Treatment was stopped in 2022 for future family planning. After pexidartinib therapy was interrupted, the patient's wife had a successful pregnancy and delivery; however, the disease showed a slow but constant clinical deterioration, with a reduction in the range of movement of the affected knee and an apparent increase in widespread TGCT nodules. Conclusion: Our case is unique because it provides support for pexidartinib use as upfront therapy for TGCT, instead of surgery, in selected cases. [ABSTRACT FROM AUTHOR]

Tenosynovial giant cell tumor (TGCT) is a rare mesenchymal tumor that clinically presents as nodular-type or diffuse-type (D-TGCT). D-TGCT is more aggressive, has a higher surgical recurrence rate, and can potentially lead to severe joint destruction. The traditional treatment is primarily through surgical intervention. Recent advancements in understanding the molecular mechanisms of the disease and the development of new drugs have significantly changed TGCT treatment strategies. Drug therapy and active surveillance have become important treatment options for unresectable or high-recurrence-risk TGCT. Imaging examinations and patient-reported outcome tools play a crucial role in evaluating efficacy and guiding treatment decisions. Comprehensive management by a multidisciplinary team and utilizing individualized treatment plans can significantly improve the quality of life and treatment outcomes of patients. Future research should explore the molecular mechanisms of TGCT, enhance multidisciplinary collaboration, and emphasize long-term management to improve treatment efficacy and patient prognosis.

Abstract Background Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive tumor of the joints, bursa, and tendon sheath that can cause considerable pain and substantial morbidity. Although surgery is the primary treatment for patients with TGCT, surgical resection is associated with high rates of recurrence, particularly for patients with diffuse TGCT. Pexidartinib, a colony-stimulating factor 1 receptor inhibitor, is approved by the US Food and Drug Administration for the treatment of adult patients with symptomatic TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Case Description A 32-year-old man presented with intra-articular diffuse TGCT with pain and received noncurative treatment for 5 years (2014–2019). In 2019, the patient was found to have extensive disease accompanied by pain and limited range of motion. The patient’s case was presented to a sarcoma multidisciplinary tumor board, who determined that surgery would cause significant morbidity and macroscopic residual tumor. As a result of the extent of disease, young age, and otherwise good health, treatment with pexidartinib was started through a compassionate use program at 800 mg/day. After dose reductions to pexidartinib at 400 mg/day and then 200 mg/day as a result of creatine phosphokinase elevations, the patient achieved a complete response after 2 years of treatment; pain was reduced and mobility was restored. The patient reported no side effects related to pexidartinib treatment. Treatment was stopped in 2022 for future family planning. After pexidartinib therapy was interrupted, the patient’s wife had a successful pregnancy and delivery; however, the disease showed a slow but constant clinical deterioration, with a reduction in the range of movement of the affected knee and an apparent increase in widespread TGCT nodules. Conclusion Our case is unique because it provides support for pexidartinib use as upfront therapy for TGCT, instead of surgery, in selected cases.

Background and Objectives: Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive, benign neoplasm arising from the synovium of joints, tendon sheaths, and bursa. There are two main subtypes of TGCT: localized-type TGCT(L-TGCT) and diffuse-type TGCT (D-TGCT). While surgical excision is still considered the gold standard of treatment, the high recurrence rate, especially for D-TGCT, may suggest the need for other treatment modalities. Materials and Methods: This study reviews current literature on the current treatment modalities for refractory-relapsed TGCT disease. Results: The gold standard of treatment modality in TGCT remains surgical excision of the tumor nevertheless, the elevated recurrence rate and refractory disease, particularly in D-TGCT indicates and underscores the necessity for additional treatment alternatives. Conclusions: TGCT is a benign tumor with inflammatory features and a potential destructive and aggressive course that can lead to significant morbidity and functional impairment with a high impact on quality of life. Surgical resection remains the gold standard current treatment and the optimal surgical approach depends on the location and extent of the tumor. Systemic therapies have been recently used for relapsed mainly cases. [ABSTRACT FROM AUTHOR]

Recently, FN1 fusions to receptor tyrosine kinase genes have been identified in soft tissue tumors with calcified chondroid matrix named calcifying chondroid mesenchymal neoplasms (CCMNs). We collected 33 cases of CCMN from the French network for soft tissue and bone tumors. We performed wholeexome RNA sequencing, expression analysis, and genome-wide DNA methylation profiling in 33, 30, and 20 cases of CCMN compared with a control group of tumors, including noncalcified tenosynovial giant cell tumor (TGCT). Among them, 15 cases showed morphologic overlap with soft tissue chondroma, 8 cases with tophaceous pseudogout, and 10 cases with chondroid TGCT. RNA-sequencing revealed a fusion of FN1 in 76% of cases (25/33) with different 5' partners, including most frequently FGFR2 (14 cases), TEK or FGFR1. Among CCMN associated with FGFR1 fusions, 2 cases had overexpression of FGF23 without tumor-induced osteomalacia. Four CCMN had PDGFRA::USP8 fusions; 3 of which had histologic features of TGCT and were located in the hip, foot, and temporomandibular joint (TMJ). All cases with FN1::TEK fusion were located at TMJ and had histologic features of TGCT with or without chondroid matrix. They formed a distinct cluster on unsupervised clustering analyses based on whole transcriptome and genome-wide methylome data. Our study confirms the high prevalence of FN1 fusions in CCMN. In addition, through transcriptome and methylome analyses, we have identified a novel subgroup of tumors located at the TMJ, exhibiting TGCTlike features and FN1::TEK fusions. [ABSTRACT FROM AUTHOR]

Giant cell tumor happens to be the second most common tumor of the hand.Being recently named as Tenosynovial Giant Cell Tumor, the localised type occurs predominantly in digits. We report a case of 23 year old female with progressive swelling in the hand which on MRI was suspected to be a Tenosynovial Giant Cell Tumor. Surgical excision of the tumor was done and was confirmed by biopsy, followed by early start of physiotherapy. On follow up there was no signs of recurrence at the end of 1 year. Hence these cases require a meticulous surgical approach and dissection for the excision and prevention of recurrence.

Diffuse-type tenosynovial giant cell tumors' (D-TGCTs) intra- and extra-articular expansion about the knee often necessitates an anterior and posterior surgical approach to facilitate an extensive synovectomy. There is no consensus on whether two-sided synovectomies should be performed in one or two stages. This retrospective study included 191 D-TGCT patients from nine sarcoma centers worldwide to compare the postoperative short-term outcomes between both treatments. Secondary outcomes were rates of radiological progression and subsequent treatments. Between 2000 and 2020, 117 patients underwent one-stage and 74 patients underwent two-stage synovectomies. The maximum range of motion achieved within one year postoperatively was similar (flexion 123-120°, p = 0.109; extension 0°, p = 0.093). Patients undergoing two-stage synovectomies stayed longer in the hospital (6 vs. 4 days, p < 0.0001). Complications occurred more often after two-stage synovectomies, although this was not statistically different (36% vs. 24%, p = 0.095). Patients treated with two-stage synovectomies exhibited more radiological progression and required subsequent treatments more often than patients treated with one-stage synovectomies (52% vs. 37%, p = 0.036) (54% vs. 34%, p = 0.007). In conclusion, D-TGCT of the knee requiring two-side synovectomies should be treated by one-stage synovectomies if feasible, since patients achieve a similar range of motion, do not have more complications, but stay for a shorter time in the hospital.

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. Plain language summary Treatment patterns in patients with tenosynovial giant cell tumors in the USA This database study is the first investigation of how drugs are used to treat patients with tenosynovial giant cell tumor (TGCT) in the real world. We researched adult TGCT patients from IQVIA's prescription and medical claims databases who started treatment with pexidartinib (N = 82) or other non-US FDA-approved systemic therapies (N = 263). The patients included in this analysis were mostly women (61.0 and 50.6%) and their median age was 47 and 54 years for pexidartinib and other non-FDA-approved systemic therapies, respectively. The patients treated with pexidartinib were most likely to remain on treatment (54.0%) at the end of the first year. Most patients (79.3%) started pexidartinib treatment at a total daily dose of 800 mg/day, as per the product label. Only 34.1% of patients had reduced medication dose during follow-up. Of note, this study found that TGCT patients were treated with other systemic therapies which remain unproven to be safe and effective in medical studies of TGCT. Given the unmet need, and with pexidartinib being the only approved systemic treatment in USA, there is an opportunity for the larger population of adult TGCT patients to benefit from its use. Further research is needed to identify barriers for access to pexidartinib and treatment of TGCT patients. Summary points Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive neoplasm affecting the synovial membrane lining joints, bursae and tendon sheaths. Pexidartinib is currently the only systemic treatment approved by the US FDA for the treatment of adult patients with symptomatic TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Other systemic therapies have been investigated in clinical studies of TGCT patients, none of them have been approved by the FDA for the treatment of TGCT specifically. Using a real-world claims database, this study characterized TGCT patients newly treated with pexidartinib or other unapproved systemic treatments and described their treatment patterns, including treatment duration and dosing. In this study, we found that although the median duration of pexidartinib treatment was not reached, patients on pexidartinib had the highest 12-month probability of remaining on treatment. Dose reductions after the first medication claim were commonly observed in the pexidartinib cohort (34.1%) and some patients (9.8%) had evidence of dose increase. Dose levels of the non-FDA-approved systemic therapies were consistent with the recommended dosages for other indications, as per their label, none of which were TGCT. As expected, 63.6–82.9% of TGCT patients treated with non-FDA-approved systemic therapies discontinued treatment at 12 months. This study provided novel insights into how systemic therapies for TGCT are used in real-world clinical practice, where surgery has been the standard of care. Given the large unmet need for the treatment of TGCT patients, and as pexidartinib is the only regulatory-approved systemic treatment, there is opportunity for its wider use in this patient population. [ABSTRACT FROM AUTHOR]

Giant cell tumor of soft tissue (GCTST) is a locally aggressive mesenchymal neoplasm of intermediate malignancy that predominantly occurs in the superficial soft tissue of the extremities. It is histologically similar to a giant cell tumor of bone (GCTB) and shows a mixture of round to oval mononuclear cells and osteoclast-like multinucleated giant cells. Currently, immunohistochemistry plays a very limited role in the diagnosis of GCTST. Primary or secondary malignant GCTST has recently been described and tumors exhibiting high-grade histological features demonstrate higher rates of distant metastasis. GCTST lacks the H3-3A gene mutations that are identified in the vast majority of GCTBs, suggesting a different pathogenesis. Surgery is the standard treatment for localized GCTST. Incomplete surgical resection is usually followed by local recurrence. Radiation therapy may be considered when the close proximity of critical structures prevents microscopically negative surgical margins. The systemic treatment options for advanced or metastatic disease are very limited. This review provides an updated overview of the clinicoradiological features, pathogenesis, histopathology, and treatment for GCTST. In addition, we will discuss the differential diagnosis of this peculiar neoplasm. [ABSTRACT FROM AUTHOR]

Tenosynovial giant cell tumor (TGCT) occurs in both diffuse and localized forms. While diffuse TGCT is an uncommon but well-described complication after total knee arthroplasty (TKA), localized TGCT has only once been previously described as a postoperative complication after TKA. We report on the diagnosis and management of a patient who developed postoperative localized TGCT after routine TKA and underwent uncomplicated removal. Postoperatively the patient noted a resolution of pain and mechanical symptoms. Early consideration of this rare occurrence after TKA can prevent significant pain and disability due to delayed diagnosis.

Tenosynovial Giant Cell Tumor (TSGCT) is a solitary, firm, and extra-articular localized benign soft tissue tumor that may present with painless swelling for many years. It usually involves the tiny joints of the extremities in the hands and feet. Here, we present the case of a male in his 20s who presented with a painful, stiff, slow-growing mass over the distal interphalangeal joint of the right-hand ring finger. Fine Needle Aspiration Cytology (FNAC) was performed and based on the microscopic features, it was reported as a case of Tenosynovial Giant Cell Tumor. Surgical excision of the swelling was performed and histopathological examination confirmed the diagnosis. The rarity of this case arises from the fact that the diagnosis of TSGCT was established on cytology, as TSGCT is very rarely reported on cytology.

We present a rare case of histiocytic sarcoma (HS) occurring in the foot of a 12-year-old male, initially misdiagnosed as localized tenosynovial giant cell tumor (TSGCT). HS is an exceptionally uncommon hematologic malignant neoplasm, with its occurrence in children and extranodal sites being even rarer. To our knowledge, this is the first reported case of extranodal HS in the foot, emphasizing comprehensive MRI findings. Initially, the patient was diagnosed with TSGCT based on histological results following surgical resection. However, after recurrence and subsequent surgical resection, histological and immunochemical analyses led to a revised diagnosis of HS. This report focuses on the MRI findings of HS, highlighting the distinctions from localized TSGCT. While both conditions share histopathological similarities, immunohistochemical tests are crucial for accurate diagnosis. The report underscores the importance of differentiating HS for appropriate treatment.

Eccrine spiradenoma is a rare tumor arising from the sweat glands. It usually presents itself in the head and neck region, with only a few reported cases in the literature of hand eccrine spiradenomas. It is usually seen in the age group of 15–35 years. Here, we report a case of a patient in her 50s presenting a mass over the dorsum of the hand and clinically closely mimicking tendon sheath giant cell tumor (GCT). Investigations supported the clinical diagnosis and provided extra information on possible malignant transformation. A surgical excision was performed and sent for histopathological examination which confirmed the diagnosis. It is also interesting to notice from our case that the need for histopathological evidence should not be neglected despite ultrasonography and Magnetic Resonance Imaging (MRI) being very useful as diagnostic investigations. [ABSTRACT FROM AUTHOR]

Tenosynovial Giant Cell Tumor (TSGCT) is a solitary, firm, and extra-articular localized benign soft tissue tumor that may present with painless swelling for many years. It usually involves the tiny joints of the extremities in the hands and feet. Here, we present the case of a male in his 20s who presented with a painful, stiff, slow-growing mass over the distal interphalangeal joint of the right-hand ring finger. Fine Needle Aspiration Cytology (FNAC) was performed and based on the microscopic features, it was reported as a case of Tenosynovial Giant Cell Tumor. Surgical excision of the swelling was performed and histopathological examination confirmed the diagnosis. The rarity of this case arises from the fact that the diagnosis of TSGCTwas established on cytology, as TSGCTis very rarely reported on cytology. [ABSTRACT FROM AUTHOR]

Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive neoplasm that occurs in the synovium of joints, bursae, or tendon sheaths and is caused by upregulation of the CSF1 gene. Vimseltinib is an oral switch-control tyrosine kinase inhibitor specifically designed to selectively and potently inhibit the CSF1 receptor. Here, we describe the rationale and design for the phase III MOTION trial (NCT05059262), which aims to evaluate the efficacy and safety of vimseltinib in participants with TGCT not amenable to surgical resection. In part 1, participants are randomized to receive vimseltinib 30 mg twice weekly or matching placebo for ≤24 weeks. Part 2 is a long-term treatment phase in which participants will receive open-label vimseltinib. Tenosynovial giant cell tumor (or TGCT) is a rare, noncancerous tumor that grows in the soft tissue lining the spaces of joints and bursae (fluid-filled sacs that work to reduce friction in the joints). These tumors are linked to increased levels of a protein called CSF1. While this condition is typically treated with surgery, some patients may not be candidates for surgical removal of the tumor due to factors such as location or complexity of the tumor; therefore, drug treatments are needed to help these patients. Vimseltinib is an investigational oral drug specifically designed to inhibit the receptor to which the CSF1 protein binds. In this article, we describe the rationale and design for a phase III clinical trial that will test how well vimseltinib works in participants with TGCT who are not candidates for surgery. In the first part of the study, participants are randomly assigned to receive vimseltinib 30 mg twice weekly or a matching placebo (inactive substance) for up to 24 weeks. This first part is blinded, so participants will not know if they are receiving vimseltinib or the placebo. The second part of the study is a long-term treatment phase in which all participants will receive vimseltinib (unblinded). Clinical Trial Registration:NCT05059262 (ClinicalTrials.gov) Vimseltinib is an oral switch-control kinase inhibitor designed to selectively and potently inhibit CSF1R. Here, we describe the rationale and design for the phase III MOTION trial, which aims to evaluate vimseltinib in participants with TGCT not amenable to surgical resection. [ABSTRACT FROM AUTHOR]

Aim: Monitoring treatment of tenosynovial giant cell tumor (TGCT) is complicated by the irregular shape and asymmetrical growth of the tumor. We compared responses to pexidartinib by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 with those by tumor volume score (TVS) and modified RECIST (m-RECIST). Materials & methods: MRIs acquired every two cycles were assessed centrally using RECIST 1.1, m-RECIST and TVS and tissue damage score (TDS). Results: Thirty-one evaluable TGCT patients were treated with pexidartinib. From baseline to last visit, 94% of patients (29/31) showed a decrease in tumor size (median change: -60% [RECIST], -66% [m-RECIST], -79% [TVS]). All methods showed 100% disease control rate. For TDS, improvements were seen in bone erosion (32%), bone marrow edema (58%) and knee effusion (46%). Conclusion: TVS and m-RECIST offer potentially superior alternatives to conventional RECIST for monitoring disease progression and treatment response in TGCT. TDS adds important information about joint damage associated with TGCT.

Background and Objectives: Tenosynovial giant cell tumor (TGCT) is a rare, locally aggressive, benign neoplasm arising from the synovium of joints, tendon sheaths, and bursa. There are two main subtypes of TGCT: localized-type TGCT(L-TGCT) and diffuse-type TGCT (D-TGCT). While surgical excision is still considered the gold standard of treatment, the high recurrence rate, especially for D-TGCT, may suggest the need for other treatment modalities. Materials and Methods: This study reviews current literature on the current treatment modalities for refractory-relapsed TGCT disease. Results: The gold standard of treatment modality in TGCT remains surgical excision of the tumor nevertheless, the elevated recurrence rate and refractory disease, particularly in D-TGCT indicates and underscores the necessity for additional treatment alternatives. Conclusions: TGCT is a benign tumor with inflammatory features and a potential destructive and aggressive course that can lead to significant morbidity and functional impairment with a high impact on quality of life. Surgical resection remains the gold standard current treatment and the optimal surgical approach depends on the location and extent of the tumor. Systemic therapies have been recently used for relapsed mainly cases.

Abstract Background This case reports the synchronous diagnosis of two rare unrelated diseases; leiomyosarcoma and tenosynovial giant cell tumor of the knee. It focuses on the challenges of diagnosing tenosynovial giant cell tumor, including cognitive biases in clinical medicine that delay diagnosis. It also demonstrates the pathogenic etiology of tenosynovial giant cell tumor, evidenced by the transient deterioration of the patients’ knee symptoms following the administration of prophylactic granulocyte colony-stimulating factor given as part of the chemotherapeutic regime for leiomyosarcoma. Case presentation A 37-year-old Caucasian man presented with a left groin lump and left knee pain with swelling and locking. Investigations including positron emission tomography-computed tomography and biopsy revealed leiomyosarcoma in a lymph node likely related to the spermatic cord, with high-grade uptake in the left knee that was presumed to be the primary site. His knee symptoms temporarily worsened each time granulocyte colony-stimulating factor was administered with each cycle of chemotherapy for leiomyosarcoma to help combat myelosuppressive toxicity. Subsequent magnetic resonance imaging and biopsy of the knee confirmed a tenosynovial giant cell tumor. His knee symptoms relating to the tenosynovial giant cell tumor improved following the completion of his leiomyosarcoma treatment. Conclusions Tenosynovial giant cell tumor remains a diagnostic challenge. We discuss the key clinical features and investigations that aid prompt diagnosis. The National Comprehensive Cancer Network clinical practice guidelines for soft tissue sarcoma have recently been updated to include the pharmacological management of tenosynovial giant cell tumor. Our case discussion provides an up-to-date review of the evidence for optimal management of patients with tenosynovial giant cell tumor, with a particular focus on novel pharmacological options that exploit underlying pathogenesis.

Simple Summary: Tenosynovial giant cell tumor is a benign yet aggressive neoplasm of the synovium that predominantly affects young patients. The tumor comprises two subtypes: the localized type and diffuse type, with the diffuse type exhibiting significantly higher aggressiveness. MRI stands out as the most valuable imaging modality for both its diagnosis and planning its treatment. When interpreting the initial MRI for suspected tenosynovial giant cell tumor, it is imperative to consider: (i) the characteristic findings of tenosynovial giant cell tumor, (ii) the potential findings of the diffuse type, and (iii) the tumor's resectability. In interpreting follow-up MRIs of the diffuse type after treatment, it is crucial to consider both local recurrence and the development of early osteoarthritis after surgery as well as the treatment response after systemic treatment. Recognizing the distinctive MRI findings of diffuse type tenosynovial giant cell tumor before and after treatment enhances radiologic evaluation, contributing to optimal patient management. Tenosynovial giant cell tumor (TSGCT) is a rare soft tissue tumor that involves the synovial lining of joints, bursae, and tendon sheaths, primarily affecting young patients (usually in the fourth decade of life). The tumor comprises two subtypes: the localized type (L-TSGCT) and the diffuse type (D-TSGCT). Although these subtypes share histological and genetic similarities, they present a different prognosis. D-TSGCT tends to exhibit local aggressiveness and a higher recurrence rate compared to L-TSGCT. Magnetic resonance imaging (MRI) is the preferred diagnostic tool for both the initial diagnosis and for treatment planning. When interpreting the initial MRI of a suspected TSGCT, it is essential to consider: (i) the characteristic findings of TSGCT—evident as low to intermediate signal intensity on both T1- and T2-weighted images, with a blooming artifact on gradient-echo sequences due to hemosiderin deposition; (ii) the possibility of D-TSGCT—extensive involvement of the synovial membrane with infiltrative margin; and (iii) the resectability and extent—if resectable, synovectomy is performed; if not, a novel systemic therapy involving colony-stimulating factor 1 receptor inhibitors is administered. In the interpretation of follow-up MRIs of D-TSGCTs after treatment, it is crucial to consider both tumor recurrence and potential complications such as osteoarthritis after surgery as well as the treatment response after systemic treatment. Given its prevalence in young adult patents and significant impact on patients' quality of life, clinical trials exploring new agents targeting D-TSGCT are currently underway. Consequently, understanding the characteristic MRI findings of D-TSGCT before and after treatment is imperative. [ABSTRACT FROM AUTHOR]

A 54-year-old man took antitubercular drugs for 1 year for right wrist pain, swelling, and restriction of movements, with no improvements. Magnetic resonance imaging wrist reported multiple nodules and soft-tissue mass with intraosseous erosions involving carpal bones, distal radius, and ulna. Resection of the mass, excision of the distal ulna, and wrist arthrodesis were done. The histopathology confirmed a diffuse tenosynovial giant cell tumor (TSGCT). No postoperative radiotherapy or systemic therapies were given. The patient remained symptom-free at 2 years of follow-up. Diffuse TSGCT with joint destruction and invasion of the wrist is rare. Therefore, a high index of suspicion is required before considering the most common infective etiologies in the wrist. [ABSTRACT FROM AUTHOR]

To propose a magnetic resonance imaging (MRI) prediction model for diffuse-type tenosynovial giant cell tumors (D-TSGCTs). Anatomic locations were classified and then nodularity, margin, peripheral and internal hypointensity, and bone and cartilage involvement were evaluated on MRI. Student's t -test, chi-square test, diagnostic performance, logistic regression analysis, and decision tree were performed. Nineteen intra-articular (11 localized; eight diffuse) and 55 extra-articular (44 localized; 11 diffuse) TSGCTs were included. Extra-articular D-TSGCTs showed significantly more frequent multinodular (72.7% vs. 25.0%, p = 0.009), and infiltrative lesions (90.9% vs. 34.1%, p = 0.002), without peripheral hypointensity (90.9% vs. 18.2%, p < 0.001), and contained granular internal hypointensity (72.7% vs. 31.8%; p = 0.003) with more frequent bone (81.8% vs. 27.3%; p = 0.003) and cartilage (50.0% vs. 0.0%; p = 0.038) involvement than localized-type. Intra-articular D-TSGCT also showed significance in all MRI features (100.0% vs. 9.1%, p = 0.001; 100.0% vs. 27.3%, p = 0.007; 100.0% vs. 36.4%, p = 0.018; 100.0% vs. 27.3%, p = 0.007; 50.0% vs. 0.0%, p = 0.038), except bone involvement (37.5% vs. 9.1%, p = 0.352) than localized-type. Cartilage involvement revealed the highest specificity (88.6–100.0%), regardless of location. Nodularity (100.0%; odds-ratio [OR]: 70.000) and peripheral hypointensity (90.9%; OR: 62.250) demonstrated the highest sensitivities ORs for D-TSGCT in intra-articular and extra-articular cases, respectively. MRI models for D-TSGCG beginning with the cartilage involvement in both anatomic locations and next on nodularity and peripheral hypointensity in intra-articular and extra-articular locations, respectively, exhibited sensitivity and specificity of 100% and 90.9% for intra-articular and 100% and 77.2% for extra-articular TSGCTs, respectively. MRI can suggest the risk of D-TSGCT by combining imaging features with anatomic locations. [ABSTRACT FROM AUTHOR]

Synovial chondromatosis (SC) is a condition in which benign nodular cartilaginous proliferation arises in joint synovium, bursae, or tendon sheaths, though rarely occurs in the temporomandibular joint (TMJ). A tenosynovial giant cell tumor (TGCT) is a benign type of tumor that mainly affects the fingers and knees, with rare occurrence in the TMJ also noted. Reported here is a case of TGCT secondary to SC in the TMJ. The patient was a 49-year-old woman who had been aware of joint noises during occlusion for a long period. After a few years, she visited our department with pain in the left TMJ. T2-weighted MR imaging showed joint effusion in the area corresponding to the upper joint cavity. One year after the initial visit, the patient underwent endoscopy-assisted excision of the tumor and a histopathological diagnosis of TGCT was confirmed. Mouth opening range was maintained at 45 mm with no evidence of recurrence at one year after surgery. [ABSTRACT FROM AUTHOR]

Abstract Background 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is useful for assessing location, metastasis, staging, and recurrence of malignant tumors. Tenosynovial giant cell tumor (TSGCT) is a benign tumor; however, some studies have reported that TSGCTs have a high uptake of FDG. Few studies have reported on the detailed evaluation of TSGCT using 18F-FDG-PET/CT. The purpose of the current study is to evaluate the image characteristics and locations, particularly where possible, with or without, extra-articular invasion from TSGCT of the knee in 18F-FDG-PET/CT could occur. Methods We retrospectively reviewed the patients with TSGCT who were diagnosed pathologically either by biopsy or surgical specimen. Furthermore, we evaluated the difference of the maximum standardized uptake value (SUVmax) between diffused TSGCT with extra-articular invasion and TSGCT with intra-articular localization in the knee. Results The study consisted of 20 patients with TSGCT. The mean SUVmax of TSGCT was 12.0 ± 6.50. There were five patients with TSGCT arising in the knee with extra-articular invasion and six with TSGCT with intra-articular localization. The mean SUVmax of TSGCT with extra-articular invasion and those with intra-articular localization were 14.3 ± 6.00 and 5.94 ± 3.89, respectively. TSGCT with extra-articular invasion had significantly higher SUVmax than TSGCT with intra-articular localization (p

BackgroundThe objective of this study was to report on the long-term effects of pexidartinib on tenosynovial giant cell tumor (TGCT).MethodsThis 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.ResultsOne 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).ConclusionsThis study demonstrates the prolonged efficacy and tolerability of long-term pexidartinib treatment for TGCT.

Purpose: Tenosynovial giant cell tumors (TSGCTs) are benign but aggressive lesions, and the treatment is resection. A low to intermediate signal intensity on both T1- and T2-weighted images of magnetic resonance imaging (MRI) is characteristic, which is similar to the signal intensity of muscle, and therefore can be challenging for lesion detection. T2-star (T2*)-weighted MR images reflect paramagnetic deoxyhemoglobin, methemoglobin, or hemosiderin. Methods: In 23 TSGCT patients (6 male and 17 females), the T2*MRI findings were analyzed. The tumor locations involved 10 large joints including nine knees and one ankle, 10 small joints including six fingers and four toes, as well as three wrists/hands. Results: Ten diffuse and 13 localized tumors were predominantly located in the large joints and small joints, respectively. The T2*-weighted images indicated three signal patterns of low, iso and high signal intensity compared to muscle. Low-, iso- and high-signal intensities were seen in 22 (96 %), 23 (100 %) and 12 (52 %) of the locations, respectively. To distinguish TSGCTs from the surrounding tissue, the low intensity T2*-weighted images and low to intermediate intensity T1-weighted images when compared to muscle and fluid, respectively were useful for the large joints. Low to intermediate intensity on T1- or T2-weighted images was useful to distinguish TSGCTs from subcutaneous tissue in the small joints. Conclusions: MRI using T2*-, as well as T1- and T2-weighted images, may be useful to detect lesions and assess the extent of TSGCTs in a tissue-specific manner, which is important for surgical planning.

Objective: Tenosynovial giant cell tumor (TGCT) is a rare hyperplastic condition of the joint’s synovial membrane with a high recurrence and tumor-like characteristics affecting large joints such as the hip, knee, and ankle. They often present with dull and chronic pain as well as swelling of the joint which may make the straight diagnosis challenging. The gold standard of treatment is complete resection of the lesion. In this case report, we present a knee joint TGCT in an adult patient with nonspecific clinical presentation. Case report: We introduced a 33-year-old patient presenting with some nonspecific and chronic signs and symptoms of the knee who was finally diagnosed as local TGCT. Conclusion: Considering the unusual and somehow deceptive clinical presentation of TGCT, in order to reach the right diagnosis, it should be considered as a differential diagnosis. Keywords: Tenosynovial giant cell tumor, Pigmented villonodular synovitis, arthroscopy, knee joint Level of evidence: V

Pexidartinib is a colony-stimulating factor-1 receptor inhibitor approved in the United States for treatment of adult patients with symptomatic tenosynovial giant cell tumor (TGCT) associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Because of the risk of severe and potentially fatal hepatotoxicity, pexidartinib is only available through a Risk Evaluation and Mitigation Strategy (REMS) program. Pexidartinib pharmacokinetics are influenced by the fat content of meals: compared with the fasted state, consuming a high-fat meal with pexidartinib increases pexidartinib absorption by 100%; a low-fat meal increases absorption by approximately 60%. Pexidartinib was initially authorized to be taken at 800 mg/day on an empty stomach; therefore, if this same dose of pexidartinib is taken with food, there is a risk of overexposure and potential toxicity. To reduce the risk of hepatotoxicity and improve patient compliance, pexidartinib has undergone a revised dosing regimen, from 800 mg/day (400 mg twice daily) fasted to 500 mg/day (250 mg twice daily) with a low-fat meal (approximately 11–14 g of total fat). The objective of this report is to educate clinical and allied health professionals on the revised dosing regimen and the importance of patient compliance with a low-fat meal. Healthcare professionals need to understand the rationale for the switch from pexidartinib dosing on an empty stomach to dosing with a low-fat meal and how meal composition and timing influence pharmacokinetics. Finally, we provide guidance for the healthcare team of prescribing providers, nurses, pharmacists, and dietitians who are caring for patients with TGCT on pexidartinib. It is important for healthcare providers to deliver consistent messaging on the low-fat meal requirement and help patients fit pexidartinib into their regular meal schedules. Consulting a dietitian may be helpful for patients, especially those with complex dietary needs. We provide an overview of the roles and responsibilities of each healthcare professional and outline steps to best support patients, including key questions and answers related to the revised dosing regimen. This report provides the information necessary to guide the multidisciplinary team caring for patients with TGCT and to support them through the pexidartinib dosing regimen change. [ABSTRACT FROM AUTHOR]

Background: This case reports the synchronous diagnosis of two rare unrelated diseases; leiomyosarcoma and tenosynovial giant cell tumor of the knee. It focuses on the challenges of diagnosing tenosynovial giant cell tumor, including cognitive biases in clinical medicine that delay diagnosis. It also demonstrates the pathogenic etiology of tenosynovial giant cell tumor, evidenced by the transient deterioration of the patients' knee symptoms following the administration of prophylactic granulocyte colony-stimulating factor given as part of the chemotherapeutic regime for leiomyosarcoma. Case presentation: A 37-year-old Caucasian man presented with a left groin lump and left knee pain with swelling and locking. Investigations including positron emission tomography-computed tomography and biopsy revealed leiomyosarcoma in a lymph node likely related to the spermatic cord, with high-grade uptake in the left knee that was presumed to be the primary site. His knee symptoms temporarily worsened each time granulocyte colony-stimulating factor was administered with each cycle of chemotherapy for leiomyosarcoma to help combat myelosuppressive toxicity. Subsequent magnetic resonance imaging and biopsy of the knee confirmed a tenosynovial giant cell tumor. His knee symptoms relating to the tenosynovial giant cell tumor improved following the completion of his leiomyosarcoma treatment. Conclusions: Tenosynovial giant cell tumor remains a diagnostic challenge. We discuss the key clinical features and investigations that aid prompt diagnosis. The National Comprehensive Cancer Network clinical practice guidelines for soft tissue sarcoma have recently been updated to include the pharmacological management of tenosynovial giant cell tumor. Our case discussion provides an up-to-date review of the evidence for optimal management of patients with tenosynovial giant cell tumor, with a particular focus on novel pharmacological options that exploit underlying pathogenesis. [ABSTRACT FROM AUTHOR]

Background: To investigate the clinical characteristics and surgical efficacy of localized tenosynovial giant cell tumors in children. Methods: The clinical data, surgery, and follow-up results of 17 children with localized tenosynovial giant cell tumors who visited our hospital from 2011 to 2021 were collected for statistical analysis. Results: The median patient age was 7 years and 8 months, and the ratio of males to females was 1.43 (10/7). The predilection of disease was similar in hands and feet, and the common presenting symptom was mass. One patient experienced recurrence after surgery, and one child had postoperative functional limitations. Conclusion: Extremities are common sites of localized tenosynovial giant cell tumors in children. Complete surgical resection helps reduce the recurrence rate. Level of evidence: Level III [ABSTRACT FROM AUTHOR]

Locally aggressive mesenchymal tumors comprise a heterogeneous group of soft tissue and bone tumors with intermediate histology, incompletely understood biology, and highly variable natural history. Despite having a limited to absent ability to metastasize and excellent survival prognosis, locally aggressive mesenchymal tumors can be symptomatic, require prolonged and repeat treatments including surgery and chemotherapy, and can severely impact patients' quality of life. The management of locally aggressive tumors has evolved over the years with a focus on minimizing morbid treatments. Extensive oncologic surgeries and radiation are pillars of care for high grade sarcomas, however, play a more limited role in management of locally aggressive mesenchymal tumors, due to propensity for local recurrence despite resection, and the risk of transformation to a higher-grade entity following radiation. Patients should ideally be evaluated in specialized sarcoma centers that can coordinate complex multimodal decision-making, taking into consideration the individual patient's clinical presentation and history, as well as any available prognostic factors into customizing therapy. In this review, we aimto discuss the biology, clinicalmanagement, and future treatment frontiers for three representative locally aggressive mesenchymal tumors: desmoid-type fibromatosis (DF), tenosynovial giant cell tumor (TSGCT) and giant cell tumor of bone (GCTB). These entities challenge clinicians with their unpredictable behavior and responses to treatment, and still lack a well-defined standard of care despite recent progress with newly approved or promising experimental drugs. [ABSTRACT FROM AUTHOR]

Purpose of reviewPigmented villonodular synovitis (PVNS) or tenosynovial giant cell tumor (TGCT) encompasses a wide spectrum of disease and is divided into localized and diffuse variants. Surgical resection remains the principal treatment for nearly all localized type disease and most diffuse type. Recent mechanistic understanding of the disease led to drug discovery that has opened new avenues for patients with recalcitrant disease. In this manuscript, we review the current treatment options for TGCT, presenting outcomes from traditional surgical approaches as well as those from nonsurgical approaches.Recent findingsArthroscopic and/or open surgery remains the mainstay of treatment for TGCT for the vast majority of patients. While radiosynoviorthesis and external beam radiation have been used for recalcitrant disease, recent understanding of the colony stimulating factor 1 receptor (CSF1R) pathway and its paracrine and autocrine role in TGCT has led to the development of targeted inhibitors. Their optimal role and efficacy are unclear due to limited number of high-quality studies and contradictory results; however, recent and ongoing studies suggest there may be a role for their use, especially in diffuse and/or refractory disease. Surgery remains the most common treatment for TGCT, however, there may be an increasing role for adjuvant therapies, including the new targeted agents. Weighing the side effects of these treatments against the symptomatic benefit on a patient-by-patient basis in this benign disease remains critical.

Tenosynovial giant cell tumor (TSDHT) is a slow-growing benign tumor arising from the tendon sheath or bursa. TSDHT of the foot and foot ankle has been reported much less frequently compared to the hand and knee. Morphologically it is classified as the localized form, often seen in the hand, and the diffuse form seen in large joints. Therefore, TSGCT should be considered in the differential diagnosis of the foot and ankle soft tissue tumors. Clinical and radiological findings of the intra-articular localized form of TSGCT in the ankle were presented in this study.

Abstract Background Tenosynovial giant cell tumor (TSGCT) is a benign fibrohistiocytic tumor that affects the synovium of joints, bursa, and tendon sheaths and is categorized into localized TSGCT (LTSGCT) and diffuse TSGCT (DTSGCT). LTSGCT and DTSGCT are characterized by recurrent fusions involving the colony-stimulating factor 1 (CSF1) gene and its translocation partner collagen type VI alpha 3 chain. The fusion gene induces intratumoral overexpression of CSF1 mRNA and CSF1 protein. CSF1 expression is a characteristic finding of TSGCT and detection of CSF1 mRNA and CSF1 protein may be useful for the pathological diagnosis. Although there have been no effective anti-CSF1 antibodies to date, in situ hybridization (ISH) for CSF1 mRNA has been performed to detect CSF1 expression in TSGCT. We performed CSF1 immunohistochemistry (IHC) using anti-CSF1 antibody (clone 2D10) in cases of TSGCT, giant cell-rich tumor (GCRT), and GCRT-like lesion and verified its utility for the pathological diagnosis of TSGCT. Methods We performed CSF1 IHC in 110 cases including 44 LTSGCTs, 20 DTSGCTs, 1 malignant TSGCT (MTSGCT), 10 giant cell tumors of bone, 2 giant cell reparative granulomas, 3 aneurysmal bone cysts, 10 undifferentiated pleomorphic sarcomas, 10 leiomyosarcomas, and 10 myxofibrosarcomas. We performed fluorescence ISH (FISH) for CSF1 rearrangement to confirm CSF1 expression on IHC in TSGCTs. We considered the specimens to have CSF1 rearrangement if a split signal was observed in greater than 2% of the tumor cells. Results Overall, 50 of 65 TSGCT cases, including 35 of the 44 LTSGCTs and 15 of the 20 DTSGCTs, showed distinct scattered expression of CSF1 in the majority of mononuclear tumor cells. MTSGCT showed no CSF1 expression. Non-TSGCT cases were negative for CSF1. FISH revealed CSF1 rearrangement in 6 of 7 CSF1-positive cases on IHC. On the other hand, FISH detected no CSF1 rearrangement in all CSF1-negative cases on IHC. Thus, the results of IHC corresponded to those of FISH. Conclusion We revealed characteristic CSF1 expression on IHC in cases of TSGCT, whereas the cases of non-TSGCT exhibited no CSF1 expression. CSF1 IHC may be useful for differentiating TSGCTs from histologically mimicking GCRTs and GCRT-like lesions.

Background: Giant cell tumor of the tendon sheath (GCTTS), also termed Tenosynovial giant cell tumor (TGCT), is a locally aggressive tumor which originates from tendon sheaths or bursas. Around 3–5% of these tumors arise from foot and ankle. Localized lesions in this area are often manifested as firm masses or nodules with slow but continuous progression through months and years. Pain associated with weight-bearing, as well as limitations in joint motions, may be reported, depending on tumor’s location. Surgery is the treatment of choice for the definitive removal of GCTTSs with the aim to eradicate the neoplasm and restore the lower limb’s functionality. Methods: Thirteen cases suffering from GCTTS of the foot and ankle underwent surgical resection at our institution between 2017 and 2022. For each case we recorded pre-operative and post-operative symptoms, as well as their pre-operative and post-operative functional status according to both MSTS and AOFAS scores. Eventual complications and local recurrences were reported. Results: Each patient experienced an at least mild pain before surgical treatment. The mean pre-operative MSTS and AOFAS scores were 22.8 and 70.7, respectively. The mean tumor size was 17.7 mm. Each patient received a resection with wide margins. Two cases (15.4%) had local recurrences. None had major complications at their latest follow-up. After the surgery, the mean post-operative MSTS and AOFAS scores increased to 28.3 and 92.2, respectively. Conclusion: Resection with wide margins for foot and ankle GCTTS is effective in restoring the patients’ lower limb functionality and is associated with reasonable local recurrence rates.

Background: 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is useful for assessing location, metastasis, staging, and recurrence of malignant tumors. Tenosynovial giant cell tumor (TSGCT) is a benign tumor; however, some studies have reported that TSGCTs have a high uptake of FDG. Few studies have reported on the detailed evaluation of TSGCT using 18F-FDG-PET/CT. The purpose of the current study is to evaluate the image characteristics and locations, particularly where possible, with or without, extra-articular invasion from TSGCT of the knee in 18F-FDG-PET/CT could occur. Methods: We retrospectively reviewed the patients with TSGCT who were diagnosed pathologically either by biopsy or surgical specimen. Furthermore, we evaluated the difference of the maximum standardized uptake value (SUVmax) between diffused TSGCT with extra-articular invasion and TSGCT with intra-articular localization in the knee. Results: The study consisted of 20 patients with TSGCT. The mean SUVmax of TSGCT was 12.0 ± 6.50. There were five patients with TSGCT arising in the knee with extra-articular invasion and six with TSGCT with intra-articular localization. The mean SUVmax of TSGCT with extra-articular invasion and those with intra-articular localization were 14.3 ± 6.00 and 5.94 ± 3.89, respectively. TSGCT with extra-articular invasion had significantly higher SUVmax than TSGCT with intra-articular localization (p < 0.05). Conclusions: TSGCT revealed high FDG uptake. Furthermore, SUVmax was higher in diffused TSGCT with extra-articular invasion than in intra-articular localized TSGCT; this may reflect its local aggressiveness. [ABSTRACT FROM AUTHOR]

Giant cell tumor (GCT) of tendon sheath is a benign soft-tissue neoplasm involving tendon sheaths more commonly in small joints of the fingers or toes, hips, knees, ankles, calcaneocuboid joints, and elbows. In this report, we are presenting a case of a 60-year-old male of South-east Asian origin hailing from an African subcontinent, who is a postchemo-radiotherapy-treated case of carcinoma (CA) hypopharynx, who was diagnosed with a GCT of the extensor digitorum tendon sheath of the right ring finger. The diagnostic confusion arose between GCT and fibroma or acral metastasis due to multinodular clinical appearance and history of malignancy. The clinical presentation, course of investigation, diagnosis, and management are reported. [ABSTRACT FROM AUTHOR]

Pexidartinib, an oral small molecule inhibitor of the colony‐stimulating factor 1 receptor, is approved for treatment of adults with symptomatic tenosynovial giant cell tumor associated with severe morbidity or functional limitations and not amenable to improvement with surgery. The original dosing regimen is 400 mg of pexidartinib (2 × 200‐mg capsules) twice daily, administered on an empty stomach at least 1 hour before or 2 hours after a meal or snack. Because pexidartinib is likely to be taken over an extended period of time, the ability to take pexidartinib with a meal would simplify timing of administration and potentially improve compliance. Since administering 400 mg of pexidartinib with a low‐fat meal increases exposure by ≈60% relative to the fasted state, administering 250 mg of pexidartinib with a low‐fat meal (low‐fat meal dosing regimen) was predicted to achieve an exposure similar to 400 mg administered during a fasted state (original dosing regimen). Based on clinical trial simulations with two one‐sided t‐tests and bootstrapping (ie, resampling) analyses, a bioequivalence study (n = 24) would have >90% power to conclude that the original dosing regimen (400 mg fasted twice daily) and the low‐fat meal dosing regimen (250 mg with a low‐fat meal twice daily) are bioequivalent. This report provides the outcome of the implementation of the model‐informed drug development strategy to recommend and justify a low‐fat meal dosing regimen for pexidartinib that has the potential to improve patient compliance while maintaining drug exposure. [ABSTRACT FROM AUTHOR]

Background and purpose: Localized tenosynovial giant cell tumors represent a rare benign proliferative disorder of the synovial and surrounding tissue. This condition has insidious and unspecific symptoms that make its diagnosis challenging. In most cases, localized tenosynovial giant cell tumors are described in the hand and are infrequent in larger joints. In the rare cases that affect the knee, the mass described in previous reports is located almost exclusively in the anterior compartment and meniscocapsular junction. The aim of the current study was to present a rare case of localized tenosynovial giant cell tumor. Case description: The paper describes the case of a twenty-eight years old Caucasian man with a localized tenosynovial giant cell tumor in the posterior compartment of the knee. Conclusion: The current study has identified a rare form of localized tenosynovial giant cell tumor. The findings of the presentation have a significant value for the differential diagnosis of the masses in the posterior knee compartment.

Locally aggressive mesenchymal tumors comprise a heterogeneous group of soft tissue and bone tumors with intermediate histology, incompletely understood biology, and highly variable natural history. Despite having a limited to absent ability to metastasize and excellent survival prognosis, locally aggressive mesenchymal tumors can be symptomatic, require prolonged and repeat treatments including surgery and chemotherapy, and can severely impact patients’ quality of life. The management of locally aggressive tumors has evolved over the years with a focus on minimizing morbid treatments. Extensive oncologic surgeries and radiation are pillars of care for high grade sarcomas, however, play a more limited role in management of locally aggressive mesenchymal tumors, due to propensity for local recurrence despite resection, and the risk of transformation to a higher-grade entity following radiation. Patients should ideally be evaluated in specialized sarcoma centers that can coordinate complex multimodal decision-making, taking into consideration the individual patient’s clinical presentation and history, as well as any available prognostic factors into customizing therapy. In this review, we aim to discuss the biology, clinical management, and future treatment frontiers for three representative locally aggressive mesenchymal tumors: desmoid-type fibromatosis (DF), tenosynovial giant cell tumor (TSGCT) and giant cell tumor of bone (GCTB). These entities challenge clinicians with their unpredictable behavior and responses to treatment, and still lack a well-defined standard of care despite recent progress with newly approved or promising experimental drugs.

Objective: To evaluate the long-term clinical outcome of the treatment of complete arthroscopic synovectomy combined with low-dose external radiotherapy in the knee affected by primary intra-articular diffuse tenosynovial giant cell tumor (TGCT). Methods: From May 2009 to January 2016, 18 patients with intra-articular diffuse TGCT underwent complete arthroscopic synovectomy and low-dose external-beam radiotherapy in Zhongnan Hospital were enrolled in this retrospective study. The preoperative symptoms of patients, the complications during or after the arthroscopic procedure and the recurrence were collected and recorded. Each patient was evaluated before treatment and at the follow-up visit. Efficacy evaluation criteria were based on Ogilvie-Harris score, and the evaluation of the functional ability of knee was based on the International Knee Documentation Committee (IKDC) Score. Results: The mean time from symptom onset to surgery was 9.1 ± 5.8 months (range from 3 to 29 months). The most frequent preoperative symptoms were joint effusion (100%), diffuse non-specific knee pain (66.7%), and a decreased range of motion (83.3%). Mean follow-up time was 68.0 ± 18.1 months (range from 35 to 120 months). The mean evaluation score according to the Ogilvie-Harris criteria before treatment was 3.19 ± 0.74, which corresponded to a rating of "poor". The mean score after treatment was 8.79 ± 1.57, rated as "good". The Ogilvie-Harris score was significantly increased after treatment (P = 0.003). The IKDC score of all patients increased significantly from 37.1 ± 3.8 before treatment to 83.9 ± 11.3 after treatment. The IKDC score was obviously increased after treatment (P = 0.001). No recurrence was noted at final follow-up. There were no complications during or after the arthroscopic procedure. Conclusion: The outcome of this study proved that complete arthroscopic synovectomy combined with low-dose external radiotherapy was appropriate for treating primary intra-articular diffuse TGCT of the knee joint. It could be safely and reliably used with minimal complications, fast postoperative recovery and satisfactory control of recurrence rates. [ABSTRACT FROM AUTHOR]

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.

Pigmented villonodular synovitis (PVNS) is a rare disease, its diagnosis has certain difficulties. This is due to the absence of characteristic etiological factors and clinical manifestations of PVNS, as well as the insufficient level of knowledge among doctors. The article presents a review of the literature on the diagnosis and treatment of PVNS, as well as a clinical case, which peculiarity is the late diagnosis of this disease, despite the presence of its certain clinical and morphological manifestations.