Efficacy of Outside-In Hip Arthroscopy without Traction in the Treatment of Hip Synovial Osteochondromatosis.

Arthroscopic treatments of hip synovial osteochondromatosis are mostly performed under traction, resulting in neurovascular injury or iatrogenic damage to the labrum or cartilage. This study aimed to assess the effectiveness of outside-in hip arthroscopy without traction in treating hip synovial osteochondromatosis. This retrospective study was conducted on a series of patients with hip synovial osteochondromatosis treated using outside-in hip arthroscopy without traction in our hospital between 2018 and 2020. Plain radiography and magnetic resonance imaging (MRI) scans were obtained. The Harris hip score (HHS), hip range of motion (ROM), and visual analog scale (VAS) scores were analyzed. The preoperative scores and last follow-up scores were compared with a paired-sample t test. The complications and recurrence postsurgery were recorded. This study included five patients (three male and two female) with an average age of 41 years (range 28-54 years). The mean follow-up time was 25.2 months (range 18-36 months). All patients experienced groin pain relief and improved ROM. The mean VAS score was significantly lower postoperatively (0.4 ± 0.5) than preoperatively (3.2 ± 0.8) (p < 0.001). The mean HHS improved from 58.6 ± 12.7 (range 43-73) to 89.8 ± 5.26 (range 81-95) (p < 0.001). No major complications, including infection, perineal numbness and swelling, neurotrosis, thromboembolism, or severe persistent pain, were reported. Synovial osteochondromatosis recurred in one patient after 2 years of follow-up without any obvious symptoms such as hip pain or joint locking. Therefore, no further treatment was necessary. This study showed that outside-in hip arthroscopy without traction might be a viable option for treating hip synovial osteochondromatosis, effectively and safely relieving symptoms with minimal complications, especially in patients without lesions in the central compartment.

[Pediatric soft tissue tumors : Tumors of uncertain origin]. / Kindliche Weichteiltumoren : Tumoren unklaren Ursprungs.

Soft tissue tumors of childhood are an extremely heterogeneous group of tumors that require precise diagnosis for therapy. In this article, selected tumors of uncertain origin that exhibit characteristic histological, immunophenotypical, and molecular features are addressed. Angiomatoid fibrous histiocytoma, alveolar soft part sarcoma, extrarenal rhabdoid tumor, synovial sarcoma, and desmoplastic small round cell tumor differ in their pathology, their clinical behavior, and prognosis.

Unusual manifestation of synovial sarcoma: A rare case report with elevated beta HCG level.

Synovial sarcoma is a rare type of soft tissue sarcoma that typically arises in the lower extremities and rarely in the upper extremities. Here, we present an unusual case of a middle-aged man who complained of dyspnea, dry cough, and chest pain and was found to have a mass-like lesion on the ulnar side of his left wrist during physical examination. The patient also exhibited gynecomastia and had elevated ß-human chorionic gonadotropin (ßHCG) levels. Subsequent imaging and histopathological analysis of the wrist mass confirmed the diagnosis of synovial sarcoma with disseminated lung metastasis. This article aims to provide a comprehensive overview of the clinical and pathological characteristics of synovial sarcoma, highlight the importance of considering synovial sarcoma as a differential diagnosis in patients with abnormal hormonal assays, and emphasize the need for clinicians to be vigilant about any pathologic lesions existing on the upper extremity to avoid late diagnosis and the development of advanced cancerous diseases.

Synovial sarcoma of the ethmoid sinus with extension to the cavernous sinus: a case report and literature review.

Synovial sarcomas are rare soft tissue tumors primarily affecting the extremities but can occasionally manifest in unusual locations such as the ethmoid sinus, posing diagnostic challenges. We present a case of a 38-year-old male with a 7-month history of recurrent throbbing headaches, left eye pain, and facial nerve palsy, evolving into multiple stroke episodes. Radiological studies showed extension to the cavernous sinus, raising an initial suspicion of vasculitis. Histological findings of an endoscopic biopsy, however, confirmed a monophasic synovial sarcoma. The patient was referred to a specialized center for further management. Unfortunately, he developed another stroke before receiving treatment. Management included chemotherapy and definitive radiation therapy targeting the ethmoid sinus. The patient is currently receiving ongoing palliative care for symptom management. This case underscores the importance of early diagnosis and a multidisciplinary approach in managing rare and aggressive tumors such as synovial sarcoma of the ethmoid sinus.

An Equine Protein Atlas Highlights Synovial Fluid Proteome Dynamics during Experimentally LPS-Induced Arthritis.

In human proteomics, substantial efforts are ongoing to leverage large collections of mass spectrometry (MS) fragment ion spectra into extensive spectral libraries (SL) as a resource for data independent acquisition (DIA) analysis. Currently, such initiatives in equine research are still missing. Here we present a large-scale equine SL, comprising 6394 canonical proteins and 89,329 unique peptides, based on data dependent acquisition analysis of 75 tissue and body fluid samples from horses. The SL enabled large-scale DIA-MS based quantification of the same samples to generate a quantitative equine protein distribution atlas to infer dominant proteins in different organs and body fluids. Data mining revealed 163 proteins uniquely identified in a specific type of tissue or body fluid, serving as a starting point to determine tissue-specific or tissue-type-specific proteins. We showcase the SL by highlighting proteome dynamics in equine synovial fluid samples during experimental lipopolysaccharide-induced arthritis. A fuzzy c-means cluster analysis pinpointed SERPINB1, ATRN, NGAL, LTF, MMP1, and LBP as putative biomarkers for joint inflammation. This SL provides an extendable resource for future equine studies employing DIA-MS.

An Updated Review on Treatment of Cervical Synovial Cyst.

Cervical synovial cyst (CSC) is a rare condition that often leads patients to seek medical attention due to cervical stenosis symptoms. There's ongoing debate about the best management strategy. To address this, a review of literature from the past 20 years (2003-2023) was conducted using keywords like "cervical synovial cyst," "cervical ganglion cyst," and "cervical juxtafacet cyst." Data on patient demographics, imaging characteristics, treatment methods, and clinical outcomes were collected. A total of 79 patients were diagnosed with CSCs, averaging 62.3 years old, with a slight male predominance (45 males, 34 females). Most cysts were located at the C1-2 and C7-T1 joints, with myelopathy being the most common symptom. Subaxial CSCs had a higher incidence of radiculopathy compared to axial CSCs. Most cases were treated surgically, with decompression performed with or without fusion. Patients generally reported symptom improvement regardless of the surgical method. Overall, surgical intervention effectively improved neurological symptoms associated with CSCs.

Amyloidosis and carpal tunnel syndrome: can we predict occurrence?

INTRODUCTION: Carpal tunnel syndrome, especially when bilateral, may be associated with amyloid deposits, a precursor of systemic amyloidosis. Systemic amyloidosis affects various organs, cardiac involvement having the poorest prognosis. Diagnosis is often delayed. Current treatments are only effective in the early stages of the disease. The primary objective of our study was to evaluate the incidence of amyloidosis in patients with bilateral carpal tunnel syndrome; the secondary aim was to screen for cardiac forms. MATERIAL AND METHODS: Between 2019 and 2023, we conducted a single-center prospective observational and diagnostic study to investigate the anatomical pathology of amyloid deposits in tenosynovial samples taken during open nerve release surgery on the median nerve. The tenosynovial biopsy was sent to a specific laboratory for analysis, and typing if positive. If amyloidosis was detected, the patient was referred to a specialist for a specific work-up. RESULTS: We included 54 patients, with a mean age of 67 years (range, 51-89 years): 16 men and 38 women. Sixteen analyses were positive, 12 of which were transthyretin and 4 non-typed. DISCUSSION/CONCLUSION: Bilateral carpal tunnel syndrome was predictive of amyloidosis. As synovial biopsy during surgery is simple and rapid, it should be implemented to identify amyloidosis at an early stage. This could change prognosis, by improving survival through screening and initiation of early specific treatment. LEVEL OF EVIDENCE: IV.

Complicated Mucocutaneous Leishmaniasis With Superimposed Cellulitis in an Immunocompromised Patient: A Case Report.

Leishmaniasis is a common protozoal infection that could be cutaneous (CL), mucocutaneous (MCL), or visceral. CL, which is the most common form, is typically localized. Therefore, it becomes more difficult to diagnose it when presenting with diffuse lesions. In this case, a 54-year-old man presented with skin lesions involving his trunk, extremities, and face, including the nasal mucosa. His past medical history was remarkable for MCL with synovial leishmaniasis, systemic lupus erythematosus (SLE), and non-Hodgkin's lymphoma (NHL). Skin biopsies showed intracytoplasmic leishmania amastigotes; polymerase chain reaction (PCR) was positive for leishmania DNA; and a culture from purulent skin lesions grew Pseudomonas aeruginosa. So, MCL with superimposed cellulitis was diagnosed, and the patient was treated with intravenous liposomal amphotericin B and ceftazidime. Leishmaniasis is an infection that has accurate diagnostic tests and various treatment options. However, the difficulty is in being able to suspect it clinically, as it can mimic a wide range of diseases with cutaneous involvement. Therefore, visual awareness of the spectrum of disease presentations is arguably the most challenging and important skill to acquire in the diagnosis and management of CL. This case represents a rare form of MCL.

Diagnostic Accuracy of Pre-operative Percutaneous Synovial Biopsy and Aspirate Compared with Open Biopsy for Prosthetic Shoulder Infections.

BACKGROUND: Shoulder arthroplasty revision is associated with a high prevalence of prosthetic infection, and diagnosis remains difficult. The primary aim of the study was to determine the diagnostic accuracy of percutaneous synovial biopsy (PSB) and joint aspiration compared with open culture results in detecting infection in revision shoulder arthroplasty. The second aim was to determine whether biopsy location within the shoulder was associated with culture status. METHODS: This was a multicenter prospective cohort study involving four sites and 69 patients undergoing revision shoulder arthroplasty. The cohort was 57% female with a mean age of 64 years. Preoperative fluoroscopic-guided PSB's and aspirates were carried out by a musculoskeletal radiologist prior to revision shoulder arthroplasty. The original prostheses consisted of hemiarthroplasties, total shoulder arthroplasties (TSA), resurfacing TSA, reverse shoulder arthroplasties (RSA), and antibiotic spacers. Six synovial tissue biopsies from separate regions in the shoulder were obtained both preoperatively and intra-operatively. The shoulder joint was aspirated, and synovial fluid collected, if available. Infection was considered positive in the setting of two or more matching positive cultures. The PSB cultures were considered "true positive" if the PSB cultures matched the open biopsy cultures. RESULTS: Nineteen percent had positive infection based on PSB and 23% had confirmed culture positive infections based on intra-operative biopsy. The diagnostic accuracy of PSB compared with open biopsy was as follows: sensitivity 0.37 (95% CI 0.13-0.61), specificity 0.81 (95% CI 0.7-0.91), positive predictive value 0.37 (95% CI 0.13 - 0.61), negative predictive value 0.81 (95% CI 0.70-0.91), positive likelihood ratio 1.98 and negative likelihood ratio 0.77. Of the 71 patients, aspiration yielded synovial fluid in 33 patients. Preoperative aspirates detected no infections confirmed positive by open biopsy and correctly identified 81% of absent infections. The diagnostic accuracy of aspirates compared with open biopsy was as follows: sensitivity 0%, specificity 0.81 (95% CI 0.66-0.96), positive predictive value 0%, negative predictive value 0.78 (95% CI 0.63-0.93). Biopsy location within the shoulder was not associated with infection status. DISCUSSION: Preoperative aspiration detected none of the infections proven positive via open biopsy. Although PSB was superior to synovial fluid aspirate, poor likelihood ratios suggests that PSB is not useful as an isolated test in the preoperative workup of the potentially infected patient. Biopsy location was not associated with culture status suggesting that the capsule is uniformly infected, and the location of tissue biopsies does not appear to matter.

Diagnostic Complexities and Management of Gouty Arthritis With Suspected Seronegative Rheumatoid Arthritis and Malignancy in an Elderly Male.

Rheumatoid arthritis (RA) and gout are two distinct types of inflammatory arthritis with significant morbidity. While RA is characterized by autoimmune synovitis, gout is defined by the deposition of urate crystals. Diagnosing these conditions becomes particularly challenging in patients with negative serological markers for RA, compounded by the patient's advanced age and potential for malignancy. This case involves a 77-year-old male with chronic gout, hypertension, chronic atrial fibrillation on edoxaban, diastolic congestive heart failure, and chronic kidney disease stage 3B, presenting with left knee pain and limited mobility. Despite negative serology for RA (rheumatoid factor (RF) <20.0 IU/ml, anti-CCP2 antibodies 1.2 U/mL), the clinical presentation raised suspicion for RA. Imaging revealed significant synovial hypertrophy and multiple periarticular lesions suggestive of chronic gouty tophi rather than RA or malignancy. The patient was managed with allopurinol, prednisolone, and colchicine and referred to rheumatology for further evaluation. Approximately 30% of RA patients may present with negative serological markers, complicating the diagnosis. Differentiating RA from gout is crucial due to differences in management strategies. Imaging modalities such as MRI and CT are essential in identifying characteristic changes of both conditions, such as synovial hypertrophy in RA and tophi in gout. In elderly patients, the possibility of malignancy should also be considered. This case highlights the complexity of diagnosing gouty arthritis mimicking seronegative RA, especially in elderly patients where the risk of malignancy must be considered. It underscores the need for comprehensive clinical and imaging evaluations and personalized treatment plans in managing patients with multiple comorbidities.

Rare presentation of primary synovial chondrosarcoma arising in the shoulder: a case report.

Synovial chondrosarcoma (CHS) is a rare malignant tumor arising from the synovial tissue and is often associated with synovial chondromatosis. Herein, we present a unique case of primary synovial CHS in the shoulder joint without evidence of synovial chondromatosis. A 60-year-old man presented to our hospital with a complain of left shoulder pain that persisted for 6 years, which was initially misdiagnosed as synovitis. Radiography revealed an osteolytic lesion involving the humerus and the scapula. Histologically, the tumor exhibited features of grade 2 synovial CHS, infiltrating the trabecular bones and intra-articular space. Wide resection led to a 9-year recurrence-free survival. This case underscores the challenges in diagnosing and managing synovial CHS, particularly in cases with atypical presentations lacking synovial chondromatosis, necessitating careful follow-up and adequate surgical intervention.

RNA-seq Based Transcriptome Analysis Reveals Role of Myoglobin in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which manifests as joint destruction and bone erosion, could be caused by both genetic and environmental factors. Currently, the causes of RA are unknown, and targeted therapies are often associated with side effects and contraindications. The detection rate of RA in women is higher than men (3:1), however, there is still a lack of comprehensive understanding of the relationship between sex and RA. We hypothesized gender differences in RA prevalence and their associated mechanisms by performing genome-wide transcriptome analysis of synovial biopsy samples. The results indicated that myoglobin (MB) was differentially expressed between males and females, with higher expression in males than females in healthy populations, while the opposite was observed in RA patients. MB interacted with HLA class II histocompatibility antigen, DM beta (HLA-DMB) and the inflammatory factor interleukin 6 (IL-6) in the human synovial cell line MH7A.

Prodrug Nanomedicine for Synovium Targeted Therapy of Inflammatory Arthritis: Insights from Animal Model and Human Synovial Joint Fluid.

Many patients cannot tolerate low-dose weekly methotrexate (MTX) therapy for inflammatory arthritis treatment due to life-threatening toxicity. Although biologics offer a target-specific therapy, it raises the risk of serious infections and even cancer due to immune system suppression. We introduce an anti-inflammatory arthritis MTX ester prodrug using a long-circulating biocompatible polymeric macromolecule: folic acid (FA) functionalized hyperbranched polyglycerol (HPG). In vitro the drug MTX is incrementally released through pH and enzymatic degradation over 2 weeks. The role of matrix metalloproteinases (MMPs) in site-specific prodrug activation was verified using synovial fluid (SF) of 26 rheumatology patients and 4 healthy controls. Elevated levels of specific MMPs-markers of joint inflammation-positively correlated with enhanced prodrug release explained by acid-catalyzed hydrolysis of esters by proteases. Intravenously administered 111In-radiolabeled prodrug confirmed by SPECT/CT imaging that it accumulated preferentially in inflamed joints while reducing off-target side-effects in a mouse model of rheumatoid arthritis (RA). Added FA as a targeting vector prolonged prodrug action; prodrug with 4x less MTX applied every 2 weeks was as effective as weekly MTX therapy. The preclinical results suggest a prodrug-based strategy for the treatment of inflammatory joint diseases, with potential for other chronic inflammatory diseases and cancer.

The Role of Biomarkers in Predicting Outcomes of Anterior Cruciate Ligament Reconstruction: A Systematic Review.

Background: Anterior cruciate ligament (ACL) injury is frequently associated with injuries to other parts of the knee, including the menisci and articular cartilage. After ACL injury and reconstruction, there may be progressive chondral degradation. Biomarkers in blood, urine, and synovial fluid can be measured after ACL injury and reconstruction and have been proposed as a means of measuring the associated cellular changes occurring in the knee. Purpose: To systematically review the literature regarding biomarkers in urine, serum, or synovial fluid that have been associated with an outcome measure after ACL reconstruction. Study Design: Systematic review; Level of evidence, 3. Methods: This review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The MEDLINE, Embase, CINAHL, and Web of Science databases were searched to identify studies published before September 2023 that reported on patients undergoing ACL reconstruction where a biomarker was measured and related to an outcome variable. Of 9360 results, 16 studies comprising 492 patients were included. Findings were reported as descriptive summaries synthesizing the available literature. Results: A total of 45 unique biomarkers or biomarker ratios were investigated (12 serum, 3 urine, and 38 synovial fluid; 8 biomarkers were measured from >1 source). Nineteen different outcome measures were identified, including the International Knee Documentation Committee Subjective Knee Form, Knee injury and Osteoarthritis Outcome Score, numeric pain scores, radiological outcomes (magnetic resonance imaging and radiography), rates of arthrofibrosis and cyclops lesions, and gait biomechanics. Across the included studies, 17 biomarkers were found to have a statistically significant association (P < .05) with an outcome variable. Serum interleukin 6 (s-IL-6), serum and synovial fluid matrix metalloproteinase-3 (s-MMP-3 and sf-MMP-3), urinary and synovial fluid C-terminal telopeptide of type 2 collagen (u-CTX-II and sf-CTX-II), and serum collagen type 2 cleavage product (s-C2C) showed promise in predicting outcomes after ACL reconstruction, specifically regarding patient-reported outcome measures (s-IL-6 and u-CTX-II), gait biomechanical parameters (s-IL-6, sf-MMP-3, s-MMP-3, and s-C2C), pain (s-IL-6 and u-CTX-II), and radiological osteoarthritis (ratio of u-CTX-II to serum procollagen 2 C-propeptide). Conclusion: The results highlight several biomarkers that have been associated with clinically important postoperative outcome measures and may warrant further research to understand if they can provide meaningful information in the clinical environment.

HyperArc radiotherapy for recurrent synovial sarcoma of infratemporal fossa: a rare case report and review of the literature.

Background: Synovial sarcoma (SS), a malignant and uncommon soft tissue sarcoma, typically manifests in the extremities and trunk. However, its occurrence in the infratemporal fossa (ITF) of the head and neck is exceedingly rare. Patients afflicted with SS in this anatomical region pose considerable challenges, as radical surgery is often difficult to undertake, leading to a high rate of postoperative recurrence. Moreover, it is often difficult to effectively control the tumor when the cancer relapses. Much of our understanding regarding SS of ITF stems from limited case reports, with a lack of established clinical guidelines for its management. There exists a significant clinical need for effective therapeutic approaches. Case Description: This case report documents a patient with SS of ITF, experiencing repeated recurrences despite undergoing multiple surgeries and chemotherapy treatments. The patient underwent HyperArc (HA) radiotherapy (RT) in conjunction with concurrent chemotherapy utilizing cisplatin, resulting in a remarkable 3-year follow-up period devoid of recurrence. Conclusions: The primary objective of this case report is to disseminate knowledge regarding this rare manifestation of SS of ITF, detailing the successful treatment strategy employed. In this case, we employed a comprehensive treatment strategy involving concurrent chemoradiotherapy based on HA. Our findings demonstrate that this approach was effective in achieving disease control and improving patient outcomes.

Synovial Hemangioma: An Overlooked Cause of Chronic Knee Pain in Children.

Introduction: Synovial hemangioma of the knee is a benign vascular malformation that is often misdiagnosed due to its non-specific symptoms. Case Report: We present a case involving a 7-year-old male child with chronic knee pain and swelling in the left knee, which remained undiagnosed for over 3 years. Magnetic resonance imaging revealed a synovial vascular malformation. Surgical excision of the lesion and partial synovectomy were performed, and histopathological analysis confirmed the diagnosis of synovial hemangioma. After 18 months of follow-up, there were no signs of recurrence or recurrent joint effusion. Conclusion: Synovial hemangioma of the knee, although uncommon, should be considered as a differential diagnosis in cases of chronic knee pain and swelling. En-bloc excision is the treatment of choice to prevent recurrence, yielding good clinical outcomes.

Magnetic Resonance Imaging Findings of Extensor Carpi Radialis Brevis Origin and Synovial Fold in Lateral Epicondylitis.

Purpose: Magnetic resonance imaging (MRI) is the most widely used imaging to diagnose lateral epicondylitis (LE). However, the importance of MRI findings in LE remains unclear. This study aimed to classify the signal intensity changes of the extensor carpi radialis brevis origin and the shape and length of the synovial fold using MRI and compare them with clinical symptoms. We hypothesized that MRI findings in LE are not associated with clinical symptoms. Methods: Two hundred and forty-three patients (261 elbows, mean age: 51.2 ± 8.5 years, mean duration of LE: 18.2 ± 11.3 months) who were evaluated using pretreatment MRI were included. The signal change of the extensor carpi radialis brevis origin was classified using coronal T2-weighted (T2) imaging and coronal fat-suppressed proton density T2 imaging, and the shape and length of the synovial folds were evaluated using coronal and sagittal T2 imaging. Furthermore, MRI findings were compared with clinical symptoms at the first visit. Results: The number of elbows with high signal intensity on fat-suppressed proton density T2 was 252 of 261 (96.5%), and those on T2 were 207 of 261 (79.3%). Synovial folds were observed in 231 of 261 (88.5%) of the elbows, and synovial folds having a dull shape were observed in 95 of 261 (36.4%) elbows. The length of the synovial fold was >1/3 of the radial head in 87 of 261 (33.3%) of the elbows. There was no statistically significant correlation between the MRI findings and clinical symptoms. Conclusions: A high rate of high signal intensity changes of the extensor carpi radialis brevis origin was observed, and fat-suppressed proton density T2 could detect finer signal changes than T2. Furthermore, synovial folds were found in many cases of LE. However, there was no association between MRI findings and clinical symptoms at first visit. Type of study/level of evidence: Prognostic IV.

Effective extraction of Xuetongsu and its role in preventing RA synovial hyperplasia by targeting synovial cell migration and apoptosis.

Kadsura heteroclita (Roxb) Craib also named Xuetong in Tujia ethnomedicine in China, has been traditionally employed in rheumatoid arthritis (RA) treatment. Our preceding investigations have elucidated that Xuetongsu (XTS), a triterpenoid compound predominant in Xuetong, showed excellent anti-RA-fibroblast-like synoviocytes (RAFLS) proliferation effect. However, XTS belongs to the trace components of the Xuetong plant, which poses certain limitations to the research. In this study, we designed a method that enhanced the extraction yield of XTS and explored the mechanism of its inhibition of RAFLS cell proliferation and migration in the treatment of RA. The results displayed that XTS reduced RAFLS cell proliferation, with an IC50 value of 4.68 ± 0.65 µM. A series of experimental techniques were utilized to show that XTS induce apoptosis in RAFLS cells at concentrations ranging from 4.5 to 18 µM, including wound healing assay, flow cytometry, and western blot analysis. Moreover, XTS at dosages of 0.42-0.84 mg/kg markedly attenuated paw swelling and synovial hyperplasia in arthritic rats, primarily through the inhibition of RAFLS migration and promotion of RAFLS apoptosis via High mobility group box 1 (HMGB-1)/Matrix metalloproteinase-9 (MMP-9)/MMP-13 signaling pathway and Bcl-2/Bax/Caspase-3 signaling pathway, respectively.

Differential type I and type III interferon expression profiles in rheumatoid and juvenile idiopathic arthritis.

Background: The role of type I and type III interferons (IFNs) in rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) is still poorly understood. The objective of this study was to examine the hypothesis that IFN expression profiles in the peripheral blood differ between subsets of arthritic subjects. Multiple type I and type III IFNs were examined in patients with RA and JIA, as well as among subtypes of JIA. Methods: Treatment-naïve RA and JIA patients were enrolled. Droplet digital PCR was used to measure the expression of type I, II, and III interferons in blood and synovial fluid leukocytes. Dendritic cell subsets were isolated from synovial fluid to examine IFN expression in each subset. Additionally, synovial mononuclear cells and JIA-derived fibroblast-like synoviocytes were stimulated with TNF, IFNγ, and poly(I:C) to examine inducible IFN expression. Results: The predominant type I IFN gene expressed by blood leukocytes was IFNκ and was significantly lower in RA than JIA and controls. Oligoarticular and psoriatic JIA subgroups showed higher IFNκ expression compared to polyarticular JIA and RA. JIA synovial fluid leukocytes expressed abundant IFNγ and type III IFNs (IFNλ1, IFNλ3), with distinct dendritic cell subset contributions. JIA fibroblast-like synoviocytes produced IFNß, IFNλ1, and IFNλ2 mRNA upon poly(I:C) stimulation. Conclusion: This study revealed differences in IFN expression patterns in RA and JIA, with notable differences between JIA subtypes. The expression levels of IFNκ, IFNγ, IFNλ1 and IFNλ3 in JIA suggest specific roles in disease pathology, influenced by disease subtype and joint microenvironment. This study contributes to understanding IFN-mediated mechanisms in arthritis, potentially guiding targeted therapeutic strategies.

Possible Transformation of Pseudotumor to Synovial Sarcoma in a Failed Metal-on-Metal Total Hip Arthroplasty.

Adverse local tissue reaction (ALTR) from the release of chromium and cobalt ions in metal-on-metal total hip arthroplasty (MoM THA) is a well-reported complication, but there is little evidence suggesting that this inflammatory reaction causes malignancy. We present a 69-year-old female with MoM THA who developed synovial sarcoma (SS). She underwent mass resection and revision THA. Postoperative pathologic analysis revealed the unanticipated diagnosis of SS. She subsequently underwent chemotherapy, sarcoma resection, and endoprosthetic reconstruction. We hypothesize that the SS developed from an ALTR in the setting of failed MoM THA. Given the paucity of data on possible malignant transformation of an ALTR to SS, we advise surgeons to consider potential malignancies when diagnosing ALTR in the setting of failed MoM THA bearings.