CD34+ synovial fibroblasts exhibit high osteogenic potential in synovial chondromatosis.

Synovial chondromatosis (SC) is a disorder of the synovium characterized by the formation of osteochondral nodules within the synovium. This study aimed to identify the abnormally differentiated progenitor cells and possible pathogenic signaling pathways. Loose bodies and synovium were obtained from patients with SC during knee arthroplasty. Single-cell RNA sequencing was used to identify cell subsets and their gene signatures in SC synovium. Cells derived from osteoarthritis (OA) synovium were used as controls. Multi-differentiation and colony-forming assays were used to identify progenitor cells. The roles of transcription factors and signaling pathways were investigated through computational analysis and experimental verification. We identified an increased proportion of CD34+ sublining fibroblasts in SC synovium. CD34+CD31- cells and CD34-CD31- cells were sorted from SC synovium. Compared with CD34- cells, CD34+ cells had larger alkaline phosphatase (ALP)-stained area and calcified area after osteogenic induction. In addition, CD34+ cells exhibited a stronger tube formation ability than CD34- cells. Our bioinformatic analysis suggested the expression of TWIST1, a negative regulator of osteogenesis, in CD34- sublining fibroblasts and was regulated by the TGF-ß signaling pathway. The experiment showed that CD34+ cells acquired the TWIST1 expression during culture and the combination of TGF-ß1 and harmine, an inhibitor of Twist1, could further stimulate the osteogenesis of CD34+ cells. Overall, CD34+ synovial fibroblasts in SC synovium have multiple differentiation potentials, especially osteogenic differentiation potential, and might be responsible for the pathogenesis of SC.

A case of synovial chondromatosis of the knee with 87 free bodies and review of literature.

BACKGROUND: Synovial chondromatosis is a non-malignant synovial disorder characterized by the presence of cartilage formation within the synovial membrane, leading to the emergence of multiple cartilaginous nodules that may be either attached or unattached. The presence of this anatomical feature is frequently observed in articulations such as the knee, hip, elbow, and ankle. CASE REPORT: In this study, we present a case of synovial chondromatosis in the knee joint of a healthy male in his early 60s. Notably, the patient exhibited the simultaneous presence of 87 large loose bodies. The occurrence of a substantial quantity of unattached entities of notable dimensions within the joint is highly uncommon. CONCLUSIONS: The patient had several synovial chondromas, a rare disease. Synovial chondromatosis is a benign disorder; however, growing synovium can cause pyogenic cartilage nodules. Most loose bodies in joints can abrade and degenerate articular cartilage, causing long-term discomfort. Thus, an early-stage procedure to remove loose bodies and carefully excise synovial tissue is necessary to treat this condition.

COL3A1 is a potential diagnostic biomarker for synovial chondromatosis and affects the cell cycle and migration of chondrocytes.

BACKGROUND: Synovial chondromatosis (SC) primarily affects the major joints and is characterized by the formation of benign cartilaginous nodules. In the present study, we evaluated the differences in the histology and gene expression of SC and normal cartilages and further elucidated the function of hub genes in SC. METHODS: Histological staining and biochemical analysis were performed to measure collagen and glycosaminoglycan (GAG) contents in SC and normal cartilage samples. Then, microarray analysis was performed using knee joint samples (three normal and three SC samples) to identify the differentially expressed genes (DEGs). Subsequently, bioinformatics analysis was performed to identify the hub genes and explore the mechanisms underlying SC. The intersection of the top 10 upregulated DEGs, top 10 downregulated DEGs, and hub genes was validated in SC tissues. Lastly, in vitro experiments and our clinical cohort were used to determine the potential biological functions and diagnostic value, respectively, of the most significant gene. RESULTS: The GAG and collagen contents were comparable to or higher in SC tissues than in normal tissues. Microarray analysis revealed 143 upregulated and 107 downregulated DEGs in SC. Furthermore, functional enrichment analysis revealed an association between immunity and metabolism-related pathways and SC development. Among 20 hub genes, two intersection genes, namely, collagen type III alpha 1 chain (COL3A1) and HSPA8, were notably expressed in SC tissues, with COL3A1 exhibiting a more significant difference in mRNA expression. Furthermore, COL3A1 can promote chondrocyte migration and cell cycle progression. Additionally, clinical data revealed COL3A1 can be a diagnostic marker for primary SC (AUC = 0.82) and be a positive correlation with neutrophil-to-lymphocyte ratio. CONCLUSIONS: These results suggest that SC tissues contained the abundant GAG and collagen. COL3A1 can affect the function of chondrocytes and be a diagnostic marker of primary SC patients. These findings provide a novel approach and a fundamental contribution for diagnosis and treatment in SC.

Synovial chondromatosis: a case series and review of the literature.

This case series reviews 2 patients worked up and treated for unilateral synovial chondromatosis of the temporomandibular joint (TMJ). The first was a 58-year-old female evaluated and treated for synovial chondromatosis of the left TMJ using an arthrotomy of the joint to remove the cartilaginous and osteocartilaginous nodules. The second is a 63-year-old male who was evaluated and treated for synovial chondromatosis of the right TMJ with the removal of extracapsular masses and an arthrotomy with intra-joint removal of nodules. Six-year radiographic follow-up demonstrated no recurrence of the pathology in his case. The cases are reviewed in this article, along with a current review of the literature.

Arthroscopic management of synovial chondromatosis with skull base perforation: A case report and literature review.

OBJECTIVE: Synovial chondromatosis (SC) of the temporomandibular joint (TMJ) is a synovial membrane disease characterized by the formation of cartilaginous nodules (CN), that may erode the skull base. Historically, cases with skull base involvement have been treated with open surgery. We report a case of TMJ SC with skull base perforation treated and repaired via minimally invasive TMJ arthroscopy and describe the advanced endoscopic operative maneuvers performed. CASE REPORT: A 34-year-old male presented with a 4-year history of malocclusion and right TMJ arthralgia. Clinical examination demonstrated malocclusion and direct pressure loading pain. Advanced imaging revealed glenoid fossa erosion and numerous homogenous hypointense lesions within an effusion. The initial surgical plan included diagnostic TMJ arthroscopy followed by conversion to open arthroplasty. Endoscopic operative maneuvers allowed for the accomplishment of the surgical goals, completely arthroscopically. Histopathology confirmed SC, and the patient remains on observation, with relief of symptoms. CONCLUSION: Advanced arthroscopy is a viable treatment option for select cases of TMJ SC with skull base involvement that allowed for access to the joint space, retrieval of biopsy specimens and CN, and repair of the skull defect.

Synovial Chondromatosis of the Shoulder in Rheumatoid Arthritis: A Case Report and Brief Review of the Literature.

BACKGROUND: Synovial chondromatosis is an uncommon benign condition characterized by synovial membrane proliferation and metaplasia. Synovial chondromatosis cases in patients with rheumatoid arthritis have been reported. However, involvement of the glenohumeral joint is rare. CASE PRESENTATION: We herein report a case of a rare association of synovial chondromatosis involving the shoulder in a rheumatoid arthritis patient. The symptoms have improved with anti-tumor necrosis factor drugs. Consequently, there was no need for invasive therapy to treat synovial chondromatosis. CONCLUSION: Synovial chondromatosis can be aggressive and destructive. More trials are needed to establish a better clinical diagnostic strategy and pharmacological management.

Synovial chondromatosis of the temporomandibular joint-clinical, surgical, and imaging findings of a Milgram stage III case series.

Synovial chondromatosis of the temporomandibular joint (TMJ) is a rare disease characterized by cartilaginous metaplasia of the mesenchymal remnants of the synovial membrane with formation of loose cartilaginous nodules. It is prevalent in middle-aged women and the main clinical characteristics are swelling, pain, and limited jaw movements. Diagnosis is difficult, especially in the early stages, because the signs and symptoms are like other TMJ diseases such as internal derangements and tumors. Imaging exams are fundamental in differential diagnosis for detection of synovitis and free cartilaginous bodies. Magnetic resonance imaging with a gadolinium contrast would be of particular interest for this purpose. Treatment involves the removal of the cartilaginous nodules and synovectomy. It can be performed by arthroscopy or arthrotomy depending on the size of the lesion, the number of corpuscles, and the need for auxiliary surgical procedures. Final diagnosis is anatomopathologic. Postoperative follow-up is necessary due to the risk of recurrence.

[Diagnosis and differentiation diagnosis of primary temporomandibular joint cartilage and giant cell related tumor lesions].

Cartilage and giant cell-related neoplastic lesions originating in the temporomandibular joint region have similar clinical, imaging and pathological manifestations, making the diagnosis of these disorders challenging to varying degrees. Diagnostic findings can influence treatment procedures and a definitive pathological diagnosis is important for the prognosis of these conditions. In this article, we discuss the pathological diagnosis and differentiation of four benign cartilage and giant cell related tumors and tumor-like lesions that occur in the temporomandibular joint, namely synovial chondromatosis, tumoral calcium pyrophosphate deposition disease, pigmented villonodular synovitis and chondroblastoma, taking into account their clinical features and histological manifestations, with a view to providing a basis for clinical management.

Synovial osteochondromatosis mimicking juvenile idiopathic arthritis in an adolescent: a case-based review.

Synovial osteochondromatosis is an extremely rare benign condition in children and adolescents that have joint pain as a presenting manifestation. It is usually monoarticular with the knee as the most common affected joint. In this article, we describe the case of a female adolescent suffering from debilitating chronic right knee pain initially mimicking juvenile idiopathic arthritis, who was subsequently diagnosed with primary synovial osteochondromatosis. We present a review of synovial osteochondromatosis focusing on the clinical manifestations, radiographic features, histopathologic findings, and treatment, with a summarized review of pediatric patients with initial musculoskeletal presentations who were ultimately diagnosed as synovial osteochondromatosis. Although synovial osteochondromatosis is rare in children and adolescents, this condition should be included in the differential diagnosis of joint pain and may mimic juvenile idiopathic arthritis. Appropriate diagnostic radiography, including both plain radiography and magnetic resonance imaging, is necessary to accurately diagnose this condition. We also emphasize the importance of a multidisciplinary team approach to managing patients with synovial osteochondromatosis.

Concomitant lipoma arborescens and synovial osteochondromatosis of the knee.

Intra-articular masses are not a rare finding in routine imaging. This is particularly true in patients with underlying joint diseases such as degenerative arthritis. Nevertheless, concomitant presentation is rather uncommon in imaging studies. The authors report an unusual concomitant lipoma arborescens and synovial osteochondromatosis (which has not previously been reported in the literature to the best of the authors' knowledge) in a man in his 60 s with a long-standing history of knee osteoarthritis. In this case presentation, we review the differential diagnosis for noninfectious synovial proliferative disorders presenting as intra-articular masses, their potential association with underlying joint pathology, and discuss the key imaging features and appropriate treatment.

Evaluation and Management of Intra-Articular Tumors of the Knee.

Intra-articular tumors of the knee are most commonly benign. Overall, this is a relatively rare clinical presentation. The differential diagnosis includes pigmented villonodular synovitis, synovial chondromatosis, lipoma arborescens, synovial hemangioma, and very rarely primary sarcoma (synovial sarcoma being the most common). The clinical presentation for these conditions is usually non-specific, but radiographic and advanced imaging findings are able to differentiate some of these tumors. It is essential to obtain and send tissue specimens to pathology for histologic analysis to rule out a primary malignancy as a missed diagnosis can have grave implications on patient outcomes. This review summarized key aspects of diagnosis and treatment for these conditions.

Primary synovial chondromatosis: an elemental investigation of a rare skeletal pathology.

BACKGROUND: Primary synovial chondromatosis (PSC) is a rare idiopathic pathology characterised by the formation of osseocartilaginous nodules within synovial joints, tendons, or bursae. The mineralisation pattern of PSC nodules is poorly understood and has yet to be investigated using elemental analysis. Mapping this pattern could elucidate the progression of the disease. MATERIALS AND METHODS: Primary synovial chondromatosis nodules discovered during dissection of a formalin fixed donor were analysed. Scanning electron microscopy paired with energy dispersive X-ray spectroscopy (SEM-EDS) was used to quantify calcium and phosphorus levels to distinguish mineralised components from cartilage, indicated by increased carbon and oxygen concentrations. RESULTS: Nine nodules with average dimensions 1.76 cm × 1.25 cm were identified in the semimembranosus bursa. SEM-EDS demonstrated increased calcium phosphate levels in nodular cores, while outer margins contained primarily carbon and oxygen. Quantification of these elements revealed nodular peripheries to contain 68.0% carbon, 30.2% oxygen, 0.8% calcium, and 1.0% phosphate, while cores were comprised of 38.1% carbon, 42.1% oxygen, 14.1% calcium, and 5.7% phosphate. CONCLUSIONS: Nodules were found to have mineralised cores embedded within a cartilaginous matrix. This pattern suggests disease progression is facilitated by endochondral ossification, opening the potential for new therapeutic techniques.

Diagnostic magnetic resonance imaging in synovial chondromatosis of the temporomandibular joint.

The aim of this paper was to investigate the clinical and magnetic resonance imaging (MRI) features of synovial chondromatosis (SC) of the temporomandibular joint (TMJ). Fourteen patients with SC of the TMJ were included in the study. Clinical and MRI features were analysed and divided into three types based on MRI classification: type I with loose bodies, type II with homogeneous masses, and type III with a mixture of loose bodies and homogeneous masses. All SCs occurred in the superior compartment of the TMJ. There were two patients (14%) categorised as type I, five (36%) as type II and seven (50%) as type III. Four patients (29%) had disc perforation, and nine had bone erosion; among those nine, seven (78%) had type III and two (22%) type II. Histological examination showed inflammation and calcification in the synovial membrane and, and cartilage of the hyaline type in all cases. MRI has advantages in the diagnosis of SC.

Synovial macrophages in cartilage destruction and regeneration-lessons learnt from osteoarthritis and synovial chondromatosis.

Inflammation is a critical process in disease pathogenesis and the restoration of tissue structure and function, for example, in joints such as the knee and temporomandibular. Within the innate immunity process, the body's first defense response in joints when physical and chemical barriers are breached is the synovial macrophages, the main innate immune effector cells, which are responsible for triggering the initial inflammatory reaction. Macrophage is broadly divided into three phenotypes of resting M0, pro-inflammatory M1-like (referred to below as M1), and anti-inflammatory M2-like (referred to below as M2). The synovial macrophage M1-to-M2 transition can affect the chondrogenic differentiation of mesenchymal stem cells (MSCs) in joints. On the other hand, MSCs can also influence the transition between M1 and M2. Failure of the chondrogenic differentiation of MSCs can result in persistent cartilage destruction leading to osteoarthritis. However, excessive chondrogenic differentiation of MSCs may cause distorted cartilage formation in the synovium, which is evidenced in the case of synovial chondromatosis. This review summarizes the role of macrophage polarization in the process of both cartilage destruction and regeneration, and postulates that the transition of macrophage phenotype in an inflammatory joint environment may play a key role in determining the fate of joint cartilage.

Extra-articular tenosynovial chondromatosis of the right fifth digit in a 59-year-old man: A case report and literature review.

Tenosynovial chondromatosis is a rare benign disorder characterized by formation of cartilaginous bodies within the synovia of the tendon sheaths. Most commonly present in the hands and feet. Clinical presentation and plain radiography can be inconclusive, which can lead to misclassification, most often confused as a chondroma of soft parts. In this case, we report the clinical, radiologic, and histology of a 59-year-old man who presented with a 1-year history of mass on the right fifth digit with limitation of motion secondary to this condition. Surgical excision revealed multiple cartilaginous nodules of varying size arising from the flexor tendon sheath. The diagnosis was confirmed postoperatively by surgical histopathology. The postoperative course of the patient was uncomplicated and has achieved an excellent functional recovery.

Arthroscopic treatment of synovial chondromatosis of hip joint.

PURPOSE: This retrospective study summarized the clinical, radiographic, and arthroscopic manifestation of synovial chondromatosis (SC) of the hip, along with the post-operative effect to discuss the curative effect of arthroscopic management of hip SC. METHODS: Twenty-one patients who underwent arthroscopic surgery from the same surgeon for hip SC were followed up for an average of 45 months. T-shaped capsulotomy was routinely performed in each case. Visual analog scale, range of motion, modified Harris Hip Score, and International Hip Outcome Tool score were collected preoperatively and at the time of the latest follow-up. All patients' demographics, radiographs, and arthroscopic images were collected to summarize and conclude the similarities and differences of their manifestation. RESULTS: Large wedged clumps of loose bodies demonstrated distinguishable radiographic, arthroscopic appearance and demanded a different surgical strategy. Postoperative scores were all significantly improved. One case of residual pain and two cases of residual loose bodies with no symptom related were reported at the final follow-up. All but one patient were satisfied with the outcome. CONCLUSION: Arthroscopy treatment of hip SC with T-shaped capsulotomy has demonstrated a good result in terms of clinical outcome score, recurrence rate, and complication rate. On the basis of this study, we concluded the clinical performance of large wedged clumps of loose bodies of hip SC.

Synovial chondrosarcoma: a single-institution experience with molecular investigations and review of the literature.

AIMS: To evaluate the available diagnostic histological criteria for synovial chondrosarcoma and to screen for the presence of IDH1/IDH2 mutations in a series of cases of this malignant cartilaginous neoplasm. METHODS AND RESULTS: Ten cases of synovial chondrosarcoma diagnosed at our institute were reviewed. At presentation, all tumours occurred in adults (median age, 62 years). The most common location was the knee joint (five cases), and the size at diagnosis ranged from 30 mm to 170 mm. Eight patients had secondary synovial chondrosarcomas associated with pre-existing/recurrent or concomitant synovial chondromatosis. Five patients had local recurrences and three had lung metastases. All patients with intralesional excisions developed local recurrences, whereas those who underwent wide resections did not. At last follow-up (mean, 91 months), available for nine patients, seven patients were alive and disease-free, one patient had died of disease, and one was alive with paravertebral metastases. Frequent histological features observed included loss of clustering of chondrocytes (nine cases), the presence of variable amounts of myxoid matrix (eight cases), peripheral hypercellularity (eight cases), tumour necrosis (six cases), and spindling of chondrocytes (four cases). Of the seven cases for which it was possible to evaluate bone permeation, six showed infiltration of bone marrow. All seven cases screened for mutations of exon 4 of IDH1 and IDH2 were found to be wild-type. CONCLUSIONS: Histological criteria in correlation with clinical and radiological features allow the recognition of synovial chondrosarcoma. IDH1/IDH2 mutations were not present in synovial chondrosarcoma. Adequate surgical margins are important for disease control.

Bilateral synovial chondromatosis of the elbow in an adolescent: a case report and literature review.

BACKGROUND: Primary synovial chondromatosis is a rare benign disease that occurs in the joint mucosa. CASE PRESENTATION: In this case report, a 14-year-old gymnast sustained pain in both elbows for 2 months with limited elbow joint activity. The initial diagnosis of bilateral elbow synovial chondromatosis was performed by physical examination and imaging report. Later, the patient was treated with open surgery on both sides of the elbow, including all loose bodies were removed out and the proliferative synovia were cut off. Histopathology reports confirmed synovial chondromatosis. CONCLUSIONS: The report introduced a case about synovial chondromatosis in bilateral elbow found in a 14-year-old girl, which is rarely involved in bilateral elbow and rarely found in adolescents. This case report aims to provide a treatment option for surgeons in similar situations.

Efficacy of image-guided synovial biopsy.

OBJECTIVE: A variety of benign and neoplastic lesions can affect the synovium, including pigmented villonodular synovitis (PVNS) and synovial chondromatosis. Prior to surgical resection, accurate characterization of synovial lesions is necessary for appropriate treatment planning. Additionally, recent advances in potential medical therapies for PVNS could decrease or eliminate the need for surgery in some cases. Such treatment options demand accurate characterization of synovial lesions prior to treatment. METHODS AND MATERIALS: Institutional IRB approval was obtained. We identified 54 synovial biopsies performed at our institution using a comprehensive database search under ultrasound (US) or computed tomography (CT) guidance. Cases were reviewed for pre-procedure imaging, location, biopsy approach, biopsy results, post-procedure complications, and surgical pathology if synovectomy was performed. RESULT: A total of 54 image-guided synovial biopsies were performed, 36 using CT guidance and 18 using US guidance. Six different anatomic locations were biopsied (the hip, knee, shoulder, elbow, ankle, and temporomandibular joint). Synovial tissue was obtained in 89% of cases (48/54). CT-guided biopsies had a positive yield of 86% (31/36) and US-guided biopsies had a positive yield of 94% (17/18). Surgical pathology was obtained in 30 of the cases and image-guided biopsy concordance was 90% (27/30). Of the patients taken for synovectomy, biopsy concordance of suspected neoplastic lesions was 100% (23/23). In cases of suspected neoplasm, the concordance between image-guided biopsy and surgical pathology was 96% (22/23). There were no reported complications. CONCLUSION: Image-guided biopsy of synovial lesions is safe and effective for establishing a definitive diagnosis prior to surgical or other intervention.