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

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

Locally Invasive Pigmented Villonodular Synovitis of the Wrist Treated by Arthroscopic Resection and Bone Grafting.

Pigmented villonodular synovitis (PVNS) is a benign but locally aggressive neoplasm that can affect tendon sheath, bursae, or joint. The wrist joint however is uncommonly involved and here we present a case of chronic monoarticular joint pain and swelling in a healthcare professional that was later histologically verified to be PVNS of the radiocarpal joint. The patient had a magnetic resonance imaging (MRI) performed prior to surgery which showed a locally invasive bony tumor of the scaphoid. He subsequently underwent a wrist arthroscopic evaluation and resection with bone grafting as the index surgery and made an uneventful postoperative recovery. This is a novel technique to address PVNS of the wrist as these cases are usually managed using open procedures which can lead to additional scarring and disrupt the blood supply of the joint capsule.

Rare Presentation of Giant Cell Tumors of the Tendon Sheath: Bilateral Involvement of Tendoachilles.

Giant cell tumor of tendon sheath arises from the synovium of tendon sheaths, joints, or bursa, mostly affects adults between 30 and 50 years of age, and is slightly more common in females. It corresponds to a localized form of pigmented villonodular synovitis (PVNS). Typically occur in the hand where they represent the second most common type of soft tissue tumors after synovial ganglions. Bilateral giant cell tumor of tendon sheath of tendoachilles is a rare presentation. We report the case of a 22-years-old female presenting with pain in both ankles without any history of trauma. On clinical examination, tenderness on both tendoachilles and local indurations were observed. Ultrasonography showed focal thickening of Achilles tendon bilaterally, and Doppler demonstrated increased flow in peritendinous area. MRI findings showed that most of the tumor had intermediate signal intensity and portions of the tumor had low signal intensity. Fine needle aspiration cytology confirmed the diagnosis of giant cell tumor of tendon sheath. Excision biopsy was done with no recurrence on subsequent follow-up.

Management of tenosynovial giant cell tumour of the temporomandibular joint: a systematic review.

Diffuse type tenosynovial giant cell tumour of the temporomandibular joint (D-TGCT-TMJ) is a rare proliferative disorder. The aim of this study was to perform a systematic review of the literature to summarize D-TGCT-TMJ management regimes and recurrence rates with at least 12 months of follow-up. Our secondary aim was to propose a minimum period of post-operative follow-up. A medline search for any D-TGCT-TMJ case detailing treatment, follow-up of at least 12 months, and presence of recurrence was undertaken. The following variables were extracted from the studies: patient's age and sex, presence of middle cranial fossa invasion, treatment undertaken, total length of follow-up, and presence of recurrence. All studies were assessed for bias as per the Joanna Briggs Institute systematic reviews appraisal tool. There were 63 cases reviewed and were predominantly managed with total resection (60.3%). Other modalities included: arthroplasty, subtotal resection with or without postoperative radiotherapy, medical therapy and surveillance. The recurrence rate was 9.52% and the longest follow-up period where recurrence was observed was at 60 months. Total resection and arthroplasty are common D-TGCT-TMJ management regimes. Patients with D-TGCT-TMJ should be followed up annually for at least 5 years postoperatively to assess for recurrence.

Primary pachydermoperiostosis associated with pigmented villonodular synovitis: An unknown association?

Primary pachydermoperiostosis is a rare genetic disease affecting the skin and musculoskeletal system. In contrast to secondary hypertrophic osteoarthropathy, primary pachydermoperiostosis is considered a benign condition. While a variety of associated abnormalities have been described in this form, any association with tumors was previously reported in the literature. We hereby describe the first case of a 20-year-old man with primary pachydermoperiostosis revealed by a knee synovial tumor.

Long-term Outcomes of Diffuse or Recurrent Tenosynovial Giant Cell Tumor Treated with Postoperative External Beam Radiation Therapy.

PURPOSE: Tenosynovial giant cell tumor (TGCT) is a rare proliferative disorder of synovial membrane that previously was known as pigmented villonodular synovitis. Primary treatment involves surgical resection; however, complete removal of all disease involvement is difficult to achieve. Radiation may be useful to reduce the risk of recurrence. We report and update our institutional experience treating diffuse and recurrent TGCT with postsurgical external beam radiation therapy. METHODS AND MATERIALS: We performed a retrospective chart review of 30 patients with TGCT from 2003 to 2019 treated with radiation therapy. Each patient was evaluated for demographics, radiation treatment parameters, surgical management, complications, and outcome. RESULTS: With mean follow-up of 82 months (range, 3-211), 24 patients (80%) who underwent surgery followed by radiation therapy did not experience any further relapse, and all 30 patients achieved local control (100%) with additional salvage therapy after radiation therapy. The most common site of disease was the knee (n = 22, 73%), followed by the ankle (n = 5, 16%) and the hand (n = 3, 10%). Seven patients (24%) presented at time of initial diagnosis and 23 (76%) presented with recurrent disease after surgical resection, with an average of 2.6 surgical procedures before radiation therapy. After resection, 18 of 30 patients (67%) demonstrated residual TGCT by imaging. The median radiation therapy dose delivered was 36 Gy (range, 34-36 Gy) in 1.8 to 2.5 Gy/fractions for 4 weeks. In the assessment of posttreatment joint function, 26 sites (86%) exhibited excellent or good function, 2 (7%) fair, and 2 poor (7%) as determined by our scoring system. There were no cases of radiation-associated malignancy. CONCLUSIONS: Among patients with diffuse or recurrent TGCT, postsurgical external beam radiation therapy provided excellent local control and good functional status, with minimal treatment-related complications. Postsurgical radiation therapy is a well-tolerated noninvasive treatment that should be considered after maximal cytoreductive resection to prevent disease progression and recurrence.

Arthroscopic treatment of diffuse pigmented villonodular synovitis of the elbow.

INTRODUCTION: Pigmented villonodular synovitis (PVNS) is a rare pathology of the elbow, but presents a risk of progression with cartilage destruction. Surgical treatment consists in synovectomy, as complete as possible. Arthroscopy is an excellent tool for the exploration and treatment of intra-articular lesions in the elbow, but the results in PVNS of the elbow have never been evaluated. The aim of this study was to assess the recurrence rate of PVNS of the elbow after arthroscopic synovectomy, and secondarily to assess pain, joint range of motion, functional scores and complication rate. MATERIAL AND METHODS: We performed a retrospective study of a continuous series of 8 patients operated on between February 2012 and February 2019, with a mean age of 43.7 years. The operated side was the dominant side in 75% of cases. Surgery consisted in the most complete synovectomy possible, performed arthroscopically. Recurrence, clinical evaluation, with pain at rest and on mpvement on visual analogue scale (VAS) and joint range of motion, functional MEPS and DASH scores, and any complications were collected. RESULTS: At a mean 66.4 months' follow-up, 2 patients required revision surgery for recurrence. At the last follow-up, VAS for pain at rest was 0.9 and 1.9 for pain on movement. MEPS score was 85.6 and DASH score 82.2. No neurological, vascular or infectious complications of arthroscopic synovectomy were found in our series. DISCUSSION: Arthroscopic synovectomy in the treatment of PVNS of the elbow was a reliable and safe therapeutic alternative, with a low complications rate and 2 cases of recurrence (25%) in our study. This was the first study to report the results of arthroscopic surgical treatment of elbow PVNS. LEVEL OF EVIDENCE: IV Retrospective study without control group.

[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.

Intra-articular Neoplasms and Masslike Lesions of the Knee: Emphasis on MR Imaging.

Intra-articular masses affecting the knee joint are uncommon lesions that encompass a range of neoplastic and nonneoplastic disorders. A joint mass limited to a single articulation is most commonly related to neoplastic or focal proliferative disease, whereas masses affecting multiple articulations are typically caused by underlying inflammatory arthritides, metabolic abnormalities, or systemic deposition disorders. This article focuses on those masses that present in a monoarticular fashion, emphasizing the lesions that most commonly affect the knee joint. MR imaging is the modality of choice for evaluation of knee masses, allowing specific diagnosis in most cases.

Pigmented villonodular synovitis of the temporomandibular joint with skull base extension: a retrospective case series.

Most studies on pigmented villonodular synovitis (PVNS) of the temporomandibular joint (TMJ) with skull base extension mostly are case report. Here, we summarize the clinical features, treatments, and outcomes of PVNS of the TMJ with skull base extension in a large case series. We reviewed the clinical information relating to patients diagnosed with PVNS of the TMJ with skull base extension information of patients in our center between 2011 and 2020. We reviewed 10 patients (4 males and 6 females). All cases had presented with a unilateral lesion extending the middle skull base. PVNS of the TMJ with skull base extension occurred on the left side in 6 patients (60%) and on the right side in 4 patients (40%). Of the 10 patients, pain and mass were the most prevalent symptoms. All patients received surgery and no recurrence was seen after 35.90 ± 25.35 months follow-up. Despite destructive biological behavior, surgery can achieve an excellent outcome for patients with PVNS of the TMJ with skull base extension. An en bloc resection may prevent recurrence and provide long-term relief. Radiotherapy may be reserved for subtotal excision and recurrent lesions but require further investigation.

Synoviocytes from pigmented villonodular synovitis are less sensitive to cadmium-induced cell death than synoviocytes from rheumatoid arthritis.

Pigmented villonodular synovitis (PVNS) is a rare inflammatory articular disease sharing common characteristics with rheumatoid arthritis (RA), notably hyperplasia of the synovium due to a hyperproliferation of synoviocytes, and with cancer owing to mutations of the CSF1/M-CCSF gene. Targeting synovium hyperplasia by the local delivery of Cadmium (Cd) has been already tested in vitro and in vivo models of RA and could be applied to PVNS. PVNS and RA synoviocytes were exposed to low doses of Cd. After different culture time points, a qualitative analysis was done by microscopy and quantitative measurements of apoptosis, cell viability and IL-6 production were carried. IL-6 production by PVNS synovial tissue was also quantified after Cd treatment with or without the presence of pro-inflammatory cytokines (IL-17 + TNF). Addition of Cd induced cell death in both PVNS (1 ppm) and RA (0.1 ppm) synoviocytes, which increased with time and Cd concentrations. Cd increased the percentage of apoptotic cells and decreased cell viability and IL-6 production. In all these experiments, PVNS synoviocytes were tenfold less sensitive to Cd than RA synoviocytes. Cd decreased IL-6 production by PVNS synovial tissue and its effect was enhanced with pro-inflammatory cytokines. In summary, PVNS synoviocytes show resistance to Cd-induced cell death and decreased inflammation. Intra-articular use of Cd could represent a potential therapeutic tool in PVNS.

Modified posterior approach of the knee in patients with diffuse pigmented Villonodular synovitis: case series of a single Institution's experience.

BACKGROUND: Diffuse pigmented villonodular synovitis (DPVNS) is a challenging tumor-like disorder that mainly occurs in the anterior aspect of the knee joint. The growth may sometimes extend to the posterior knee joint. Surgical excision is the mainstream treatment for DPVNS, and the posterior approach of tumor excision is adopted when the dominant tumor shows posterior extension. However, the optimal surgical approach over the posterior knee remains unknown. METHODS: Patients with DPVNS of the knee joint who received the posterior approach of synovectomy from 1995 to 2019 were retrospectively reviewed to describe the modified separate posterior (SP) approaches, and evaluate the treatment outcomes in a case series of DPVNS knees. The results of the SP approach was also compared with those of traditional direct posterior (DP) approach. Postoperative functional outcomes were evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) standardized questionnaire and clinician-completed Musculoskeletal Tumor Society (MSTS) functional rating system at outpatient department. RESULTS: A total of 20 DPVNS knees were included. Thirteen patients who received SP approaches were included in the SP group, while seven patients who received the DP approach were included in the DP group. The median follow-up times were 5.7 years (IQR, 2-8.8) in the SP group and 3 years (IQR, 2-5.3) in the DP group. Both groups showed satisfactory safety. The SP group presented higher postoperative mean WOMAC (91.23 ± 7.20) and mean MSTS (24.23 ± 2.68) than the DP group (mean WOMAC: 76.00 ± 16.57; mean MSTS: 22.43 ± 4.69). The Wilcoxon signed-rank test was use to compare preoperative and postoperative range of motion (ROM) for each group. The significant difference in SP group (p = 0.004) was found while p = 0.131 in DP group. CONCLUSIONS: The SP approach provides an effective approach with satisfactory outcomes for the surgical treatment of DPVNS knees.

Joint involvement in Noonan syndrome. A retrospective paediatric descriptive study.

OBJECTIVES: Noonan syndrome is a rare genetic disorder characterized mainly by congenital heart disease, occasional intellectual disability, and varied orthopaedic, rheumatological and haematologic anomalies. Despite potentially serious functional consequences, joint involvement has been rarely studied in the literature. Our objective was to perform a retrospective study evaluating the prevalence and characteristics of joint involvement in Noonan syndrome. METHODS: We recorded articular symptoms, including their type and frequency, in patients with Noonan syndrome followed up in French hospitals. Patients were included if the diagnosis was confirmed before the age of 20 based on the van der Burgt criteria or genetic analysis. Data are presented as frequencies or medians (ranges), and patient groups were compared using chi-square or Fisher tests. RESULTS: Seventy-one patients were included from 4 centres. The average age was 12.5 years (range: 2-36). Musculoskeletal pain was found in 18 patients (25%) and joint stiffness in 10 (14%) located in the wrists, elbows, ankles, knees and hips, which was usually bilateral. Only one destructive form was described (multiple villonodular synovitis and a giant cell lesion of the jaw). There were no cases of systemic lupus erythaematosus (SLE) or other autoimmune arthritis. Raynaud's phenomenon was observed in 3 patients. Only 50% of joint complaints led to additional exploration. SOS1 mutations (P<0.05) and treatment with growth hormone (GH) (P<0.05) were the only factors significantly related to musculoskeletal pain. Patients treated with GH did not have more SOS1 mutations. Patients experiencing pain were not more likely to experience stiffness, joint hypermobility, or coagulation abnormalities. CONCLUSION: Joint manifestations were frequent in Noonan syndrome, predominant in large joints, and rarely explored. Multiple villonodular synovitis is characteristic but rare. Auto-immune disorders were not described in this cohort. A more multidisciplinary approach could be recommended for the early detection of possibly disabling rheumatologic manifestations.

Tenosynovial giant cell tumor-diffuse type, treated with a novel colony-stimulating factor inhibitor, pexidartinib: initial experience with MRI findings in three patients.

Tenosynovial giant cell tumor-diffuse type (diffuse TSGCT) is a benign but locally aggressive proliferative disorder of the synovium. Treatment is usually surgical, although in cases of extensive disease complete synovectomy is not possible and local recurrence rates are high. Pexidartinib (trade name Turalio®), a colony-stimulating factor-1 (CSF-1) inhibitor, was shown in a recent phase III trial to effectively treat diffuse TSGCT and is FDA approved for the treatment of adult patients with symptomatic diffuse TSGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Pexidartinib is available only through a restricted program under a risk evaluation and mitigation strategy (REMS) because of the risk of hepatotoxicity. Magnetic resonance imaging (MRI) is the preferred imaging modality for the diagnosis and surveillance of TSGCT. Here we present three patients with diffuse TSGCT of the knee who underwent multiple MRIs over several years while on pexidartinib. We describe the disease burden and signal characteristics on MRI and correlate with the response reported in the patients' medical records. Given that the use of pexidartinib and other CSF inhibitors is likely to increase, musculoskeletal radiologists should be aware of this novel non-operative treatment and the MRI appearance of diffuse TSGCT during therapy.

Gene Expression Profiles Analyzed Using Integrating RNA Sequencing, and Microarray Reveals Increased Inflammatory Response, Proliferation, and Osteoclastogenesis in Pigmented Villonodular Synovitis.

Background: Pigmented villonodular synovitis (PVNS) is a rare condition that involves benign proliferation of the synovial tissue and is characterized by severe joint destruction and high recurrence even after surgical resection. However, poor understanding of the pathogenesis limits its effective therapy. Method: In this study, gene expression profiles of six patients with PVNS, 11 patients with osteoarthritis (OA), nine patients with rheumatoid arthritis (RA) (E-MTAB-6141), and three healthy subjects (GSE143514) were analyzed using integrating RNA sequencing (RNA-seq) and microarray to investigate the PVNS transcriptome. Gene ontology, string, and cytoscape were used to determine the gene functional enrichment. Cell functional molecules were detected using flow cytometry or immunohistochemical test to identify the cell subset and function. CD14+ cells were isolated and induced to osteoclast to evaluate the monocyte/macrophage function. Results: The most obvious local manifestations of PVNS were inflammation, including increased immune cells infiltration and cytokine secretion, and tumor phenotypes. High proportion of inflammatory cells, including T cells, natural killer (NK) cells, NKT cells, and B cells were recruited from the blood. Th17 and monocytes, especially classical monocytes but not nonclassical monocytes, increased in PVNS synovium. An obvious increase in osteoclastogenesis and macrophage activation was observed locally. Elevated expression of MMP9, SIGLEC 15, and RANK were observed in myeloid cell of PVNS than OA. When compared with RA, osteoclast differentiation and myeloid cell activation are PVNS-specific characters, whereas T cell activation is shared by PVNS and RA. Conclusion: The transcriptional expression characteristics of PVNS showed increased immune response, cell migration, and osteoclastogenesis. Osteoclast differentiation is only observed in PVNS but not RA, whereas T-cell activation is common in inflammatory arthritis.

Long-term functional outcomes of diffuse pigmented villonodular synovitis of knee: The role of adjuvant radiotherapy.

ABSTRACT: Diffuse pigmented villonodular synovitis (PVNS) of knee is a rare benign disease that has a destructive clinical course. Synovectomy and adjuvant radiotherapy (RT) have been reported as treatment options but literatures reporting functional outcomes were sparse. This study aimed to evaluate the long-term functional outcomes and disease control among treatment modalities through the 22 years of experience.A single-center database was searched for patients who received synovectomy of knee with the pathologic diagnosis of PVNS. General data, treatment modalities, and recurrent status were retrospectively collected from medical records. Functional outcomes were evaluated by Western Ontario and McMaster Universities Osteoarthritis Index through phone interviews by an independent orthopedist.From January 1995 to December 2017, 24 patients with diffuse PVNS of knee were identified, including 19 receiving open synovectomy (OP) and 5 undergoing arthroscopic surgery. Adjuvant RT was performed on 14 patients with a median dose of 35 Gy (range 20-40 Gy). After median follow up of 6 years, recurrences were recorded in 10 cases. The recurrence rate was significantly lower in the OP + RT group than the OP group (8.3% vs 57.1%, P = .038). Among those with preserved knee joints, there was no significant difference in the Western Ontario and McMaster Universities Osteoarthritis Index score and stiffness score between patients in the OP + RT and OP groups.For patients with diffuse PVNS of knee, the addition of moderate-dose adjuvant RT following OP provided excellent local control while maintaining good joint function with limited treatment-related morbidity. Our study emphasized the importance of moderate dose RT in diffuse PVNS of knee joint.

Spinal pigmented villonodular synovitis and tenosynovial giant cell tumor: A report of two cases and a comprehensive systematic review.

BACKGROUND AND OBJECTIVE: Pigmented villonodular synovitis (PVNS) is a lesion of uncertain etiology that involves the synovial membranes of joints or tendon sheaths, representing a diffuse and non-encapsulated form of the more common giant cell tumors of the synovium (GCTTS). PVNS was reclassified to denote a diffuse form of synovial giant cell tumor (TSGCT), while 'giant cell tumor of the tendon sheath (GCTTS)' was used for localized lesions. These pathologies rarely affect the axial skeleton. We provide an unprecedented and extensive systematic review of both lesions highlighting presentation, diagnostic considerations, treatment, prognosis, and outcomes, and we report a short case-series. METHOD: We describe two-cases and conduct a systematic review in accordance with PRISMA guidelines. RESULT: PVNS was identified in most of the cases reviewed (91.6 %), manifesting predominantly in the cervical spine (40 %). Patients commonly presented with neck pain (59 %), back pain (53 %), and lower back pain (81.2 %) for cervical, thoracic, and lumbar lesions, respectively. GTR occurred at rates of 94 %, 80 %, and 87.5 %. Recurrence was most common in the lumbar region (30.7 %). GCTTS cases (8%) manifested in the cervical and thoracic spine at the same frequency. We reported first case of GCTTS in the lumbosacral region. Both poses high rate of facet and epidural involvements. CONCLUSION: Spinal PVNS and GCTTS are rare. These lesions manifest most commonly as PVNS within the cervical spine. Both types have a high rate of facet and epidural involvement, while PVNS has the highest rate of recurrence within the lumbar spine. The clinical and radiological features of these lesions make them difficult to differentiate from others with similar histogenesis, necessitating tissue diagnosis. Proper management via GTR resolves the lesion, with low rates of recurrence.

cIAP2 expression and clinical significance in pigmented villonodular synovitis.

Pigmented villonodular synovitis (PVNS) is a rare hyperplasia disease of the synovium with a predilection for the knee in either a localized (LPVNS) or a diffuse form (DPVNS). But the exact cause is not clear. The aim of this study was to explore the relationship between the expression of cellular inhibitor of apoptosis 2 (cIAP2) and proliferation, apoptosis, invasive growth and postoperative recurrence in PVNS. Clinical significance of cIAP2 expression in synovium from 63 patients' knee joints with PVNS (40 DPVNS; 23 LPVNS) were investigated with 20 normal subjects acting as controls. The cIAP2 gene was screened by Human Cancer Pathway Finder PCR Array and real-time polymerase chain reaction (RT-PCR). We also used immunohistochemistry to detect cIAP2 and proliferating cell nuclear antigen (PCNA) protein expression and analyzed their relationship with PVNS type, invasive growth, and postoperative recurrence. The expression of cIAP2, PCNA, caspase-8, caspase-9 and caspase-3 protein was tested in Western blot. Screening results of Human Cancer Pathway Finder PCR array and RT-PCR showed significantly more cIAP2 mRNA in DPVNS synovium than in normal or LPVNS synovium (P < 0.05). Immunohistochemistry and western blot showed that the cIAP2 protein expression level in DPVNS was significantly higher than in LPVNS tissue (P < 0.01). As cIAP2 expression increased, the expression of PCNA increased (P < 0.05) and expression of cleaved caspase-3, -8, -9 decreased (P < 0.01). cIAP2 and PCNA overexpression were found to be related to ligament and bone erosion in PVNS and to disease recurrence (P < 0.05). This study suggested that cIAP2 overexpression plays an important role in the anti-apoptotic, proliferative and invasive growth of PVNS, which may account for the recurrence and poor prognosis of DPVNS.

MR imaging findings for differentiating nonhemophilic hemosiderotic synovitis from diffuse-type tenosynovial giant cell tumor of the knee.

PURPOSE: To evaluate the differences in MR findings between nonhemophilic hemosiderotic synovitis (HS) and diffuse-type tenosynovial giant cell tumor (D-TGCT) of the knee. METHODS: This study included 13 patients with histopathologically confirmed intra-articular hemosiderin deposition of the knee (eight with nonhemophilic HS and five with D-TGCT) who underwent preoperative MR imaging including T2*-weighted images (T2*WI). We retrospectively reviewed the MR images and compared MR findings between the two pathologies. RESULTS: Lateral meniscus tear and lateral articular cartilage injury (88% vs. 20%, p < 0.05) and distribution in the suprapatellar bursa of the maximum thickness of T2* hypointense synovium (75% vs. 0%, p < 0.05) were significantly more frequent in nonhemophilic HS than in D-TGCT, respectively. Among patients who underwent contrast-enhanced imaging, all five patients with nonhemophilic HS showed minimal to mild enhancement of the thickened synovium with superficial linear enhancement, whereas all four patients with D-TGCT showed moderate to severe enhancement (p < 0.01). CONCLUSION: As compared with D-TGCT, lateral meniscus tear, lateral articular cartilage injury, lesser degree of contrast enhancement of the thickened synovium, and distribution in the suprapatellar bursa of the maximum thickness of T2* hypointense synovium were characteristic features of nonhemophilic HS.

Cadherin-11 cooperates with inflammatory factors to promote the migration and invasion of fibroblast-like synoviocytes in pigmented villonodular synovitis.

Rationale: Pigmented villonodular synovitis (PVNS) is a destructive benign tumor-like hyperplastic disease that occurs in synovial tissue. Fibroblast-like synoviocytes (FLS) are the predominant cell type comprising the structure of the PVNS synovial lining layer. Due to a high recurrence rate, high invasion, migration, and cartilage destruction ability, PVNS causes substantial damage to patients and the efficacy of surgical resection is not satisfactory. Therefore, exploring the pathogenesis and identifying novel therapeutic targets for PVNS are urgently required. Currently, the pathogenesis of PVNS remains unclear, and there is uncertainty and controversy regarding whether PVNS is an inflammatory or a neoplastic disease. Cadherin-11 is a classical molecule that mediates hemophilic cell-to-cell adhesion in FLS and plays an important role in the normal synovium lining layer formation. This study aimed to explore the role of inflammation and cadherin-11 in PVNS pathogenesis and determine the effects of cadherin-11 as a molecular target for PVNS treatment. Methods: FLS were primarily cultured from PVNS patients during arthroscopic synovectomy. The level of cytokines in the PVNS synovial fluid was evaluated using a human antibody array. Cadherin-11 expression of PVNS FLS was detected by qPCR, Western blots, tissue immunohistochemistry, and cell immunofluorescence. Cadherin-11 was down-regulated by siRNA or up-regulated with a plasmid, with or without inflammatory factor stimulation, and PI3K/Akt was inhibited with LY294002. The capacity of migration and invasion of PVNS FLS was tested using Transwell and wound-healing assays. Activation of the nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways was detected by Western blots. Chondrocyte damage by PVNS FLS was assessed with a co-culture assay. Results: Inflammatory factors (IL-1ß and TNF-α) in the synovial fluid of PVNS patients were significantly up-regulated. Cadherin-11 was highly expressed in the FLS of PVNS patients, and positively correlated with recurrence, extra-articular migration, and cartilage destruction of PVNS. Knocking down of cadherin-11 inhibited the migration and invasion of PVNS FLS. Moreover, inflammatory factors up-regulated the expression of cadherin-11, which activated the NF-κB and MAPK signaling pathways and led to cartilage destruction. Inhibition of cadherin-11 blocked IL-1ß- and TNF-α-induced activation of the above pathways, migration and invasion of PVNS FLS, and damage of chondrocyte. In addition, the elevation of cadherin-11 expression, together with the migration and invasion, of PVNS FLS was down-regulated by the inhibition of the PI3K/Akt signaling pathway. Conclusions: Cadherin-11 plays an important role in the pathogenesis of PVNS and forms a positive feedback loop with inflammatory factors, which further activates the NF-κB and MAPK pathways to trigger an inflammatory cascade. Cadherin-11-mediated inflammation results in PVNS with high recurrence, invasiveness, and strong cartilage destruction ability, and eventually promotes the transformation of PVNS from the initial inflammatory disease to neoplastic disease. Thus, inhibition of cadherin-11 together with its related inflammatory reaction, represents a new therapeutic strategy for PVNS.