Intra and extraarticular localized pigmented villonodular synovitis

<p class="abstract">A 28 year old woman had a history of knee trauma and presented with unilateral knee acute swelling and pain symptoms with sudden onset, which was there from last 2 years. She had been treated for seronegative rheumatoid patient for 1 year. Recent expansion of the LPVNS (localized pigmented villonodular synovitis) caused the development of a tender palpable soft tissue mass in the anterolateral aspect of the knee and acute reduced mobility. Preoperative magnetic resonance imaging of the knee revealed the presence of only the soft tissue mass and mild degenerative changes. Open synovectomy was performed successfully to excise the mass. Intraoperatively, macroscopic features of the bright brown inflamed synovium suggested LPVNS, which was confirmed histopathologically. Postoperatively, the symptoms of limited mobility and pain were appreciably relieved. Recurrence was not observed during the clinical follow up at 1, 6 or 18 months after surgery. Here, we reported the unique case of localized pigmented villonodular synovitis of the knee in a misdiagnosed patient with intra and extraarticular lesion, which might be attributed to the history of knee trauma and the focal defect of the lateral patellar retinaculum. Open synovectomy effectively relieved the symptoms of limited mobility and pain and no recurrence was observed prior to 18 months postoperatively. To reduce misdiagnosis, MRI examinations are recommended for all patients suspected of having PVNS, including those who have a history of hyperuricemia.</p>

Clinical Outcomes of Endoscopic Synovectomy With Adjuvant Radiotherapy of Pigmented Villonodular Synovitis of The Hip: A Case Series of Single Center

Background: Though radiotherapy has been widely used for knee pigmented villonodular synovitis (PVNS), there is few literatures about radiotherapy for the treatment of PVNS hip. Thus, the purpose of this study was to analyze the clinical outcomes of endoscopic synovectomy with/without radiotherapy postoperatively of PVNS hip.Methods: We performed a retrospective study of patients who underwent endoscopy in our hospital from November 2010 to January 2021. Patients with magnetic resonance image (MRI) signs, endoscopic findings and/or histological evidence of PVNS were included. All patients underwent synovectomy endoscopically and were divided into two groups depending on receiving postoperative radiotherapy or not. The primary outcome measurements were the recurrence of PVNS, receiving revision, and/or converting to total hip arthroplasty (THA). The secondary outcome measurements were the patient-reported outcome (PRO) collected at pre- and post-operation, which consist of Hip Outcome Score Activities of Daily Living (HOS-ADL), modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (IHOT-12), Non-arthritic Hip Scale (NAHS), and visual analog scale (VAS).Results: In a case series of 16 patients (8 cases of male, 50%), 4 (25%) cases were localized type and 12 (75%) cases were diffuse type. The average follow-up was 44.8±38.2 months (range,3 to 110). 8 (50%) cases (6 diffuse cases and 2 localized cases) received radiotherapy postoperatively, and the rest (6 diffuse cases and 2 localized cases) received endoscopic treatment alone. At the latest follow-up, 3 (18.75%) cases (2 diffuse cases and 1 localized case) who did not receive radiotherapy converted to arthroplasty. The preoperative HOS-ADL, mHHS, IHOT-12, NAHS, VAS scores of remaining 13 patients were 63.1±19.1 (range,32.0 to 98.8), 54.8±20.1 (range, 10.0 to 77.0), 50.9±15.4 (range, 31.0 to 76.6) ,51.6±15.9 (range, 20.0 to 84.4), 6.0±1.4 (range,4.0 to 8.0) points, respectively. The latest HOS-ADL, mHHS, IHOT-12, NAHS, VAS scores of the 13 patients were 79.7±10.8 (range, 58.0 to 97.6), 78.6±9.1 (range,55.0 to 87.0), 74.7±9.7 (range, 55.6 to 91.0), 78.9±18.7 (range,20.0 to 92.5), 3.1±1.2 (range,2.0 to 6.0) points respectively. There was a statistically significant difference between pre- and post-operation PRO.Conclusion: Endoscopic synovectomy can achieve satisfactory PRO in PVNS hip patients. Besides, postoperative adjuvant radiotherapy can achieve higher hip survivability than synovectomy alone in this present study.

Single-cell RNA-seq analysis reveals aberrant CSF1 expression in disease-causing synovial fibroblasts of pigmented villonodular synovitis

Objectives: Although the role of the CSF1/CSF1R axis in pigmented villous synovitis (PVNS) has been confirmed, the cells that express CSF1 and CSF1R and the underlying mechanism remain unclear. Single-cell RNA sequencing (scRNA-seq) of PVNS obtained through biopsies depicted the cellular diversity of PVNS, revealed specific CSF1/CSF1R-expressing cells and further identified novel gene expression that is associated with the development of PVNS. Methods: scRNA-seq was performed on tissues obtained from the 6 biopsies of 3 patients with PVNS. Flow cytometry, immunofluorescence and western blot validated the transcriptional results, while co-culture systems revealed the cross talk between fibroblasts and macrophages. Results: 8 subsets of fibroblasts and 5 subsets of macrophages were identified from the synovium of patients with PVNS and were found to be related to distinct signaling pathways. The cellular components of localized and diffuse PVNS are overall similar. Moreover, the synovium and nodule of PVNS share similar composition. The specific cells expressing CSF1/CSF1R were also identified. Other than that, unique CXCL12+CSF1+ fibroblasts were revealed to attract macrophages as disease-causing synovial fibroblasts, leading to the formation of masses in PVNS. Conclusions: PVNS consists of macrophages, fibroblasts, T cells, endothelial cells and mast cells. Among them, the CSF1-expressing fibroblasts appeared to be tumor-like cells that attract macrophages, subsequently forming tumor-like mass in PVNS. This paves the path for novel treatments of PVNS by targeting CXCL12+CSF1+ fibroblasts and the CXCL12-CXCR4 axis.

Pigmented Villonodular Synovitis of the Temporomandibular Joint with Skull Base Extension: A Retrospective Case Series

Background: Pigmented villonodular synovitis (PVNS) of the temporomandibular joint (TMJ) with skull base extension is a rare entity. Here, we summarize the clinical features, treatments, and outcomes of PVNS of the TMJ with skull base extension in a large case series. Methods: 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. Results: 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. Conclusion: 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.