BACKGROUND: pigmented villonodular synovitis (PVNS) is a benign condition that affects the knee, leading to abnormal proliferation of the synovial membrane and the accumulation of hemosiderin in the joint cavity. Although it can be surgically treated, PVNS tends to have a high recurrence rate, potentially resulting in chronic joint damage.
METHODS: we present the case of a young woman who experienced localized pain in her right knee due to a recurrence of PVNS. Magnetic resonance imaging revealed multiple multilobulated cystic lesions affecting the entire joint, including the ligaments. The patient underwent open surgical resection with a favorable clinical outcome. Histopathological examinations confirmed the absence of malignancy.
CONCLUSIONS: while arthroscopy is typically the preferred treatment for PVNS, this case highlights the tendency for recurrence associated with this approach. Open surgical resection, supported by benign histopathological findings in this case, suggests a favorable long-term prognosis.
UNASSIGNED: la sinovitis villonodular pigmentada (SVNP) es una enfermedad benigna que afecta la articulación de la rodilla, que causa una proliferación anormal de la membrana sinovial y la acumulación de hemosiderina en la cavidad articular. A pesar de que es posible tratarla mediante cirugía, la SVNP tiende a tener una alta tasa de recurrencia, lo que puede resultar en daño articular crónico.
UNASSIGNED: se presenta el caso de una mujer joven que experimentó dolor localizado en la rodilla derecha debido a una recurrencia de SVNP. La resonancia magnética reveló múltiples lesiones quísticas multilobuladas que afectaban a toda la articulación, incluyendo los ligamentos. La paciente fue sometida a una resección quirúrgica abierta, con una evolución clínica favorable. Los exámenes histopatológicos confirmaron la ausencia de malignidad.
UNASSIGNED: aunque la artroscopía se considera el tratamiento de elección para la SVNP, este caso ilustra la tendencia a la recurrencia asociada con este enfoque. La resección quirúrgica abierta, respaldada por los hallazgos histopatológicos benignos en este caso, sugiere un pronóstico favorable a largo plazo.

Tumors resembling tenosynovial giant cell tumor (TGCT) but additionally forming chondroid matrix (C-TGCT) are rare and most often involve the temporomandibular joint (TMJ). We studied 21 tumors consisting of synoviocytes (large, eosinophilic mononuclear cells containing hemosiderin) and chondroid matrix to better understand these unusual neoplasms. The tumors occurred in 10 males and 11 females, ranging from 31-80 years (median, 50 years) and involved the temporomandibular joint region (16), extremities (4), and spine (1). As in conventional TGCT, all were composed of synoviocytes, small histiocytes, foamy macrophages, siderophages and osteoclast-like giant cells in variably hyalinized background. Expansile nodules of large, moderately atypical synoviocytes were present, in addition to \"chondroblastoma-like\", \"chondroma-like\", or \"phosphaturic mesenchymal tumor-like\" calcified matrix. The synoviocytes expressed clusterin (17/19) and less often desmin (3/15). The tumors were frequently CSF1-positive by CISH (8/13) but at best weakly positive for CSF1 by IHC (0/3). Background small histiocytes were CD163-positive (12/12). All were FGF23-negative (0/10). Cells within lacunae showed a synoviocytic phenotype (clusterin-positive; S100 protein and ERG-negative). RNA-seq was successful in 13 cases; fusions were present in 7 tumors, including FN1::TEK (5 cases), FN1::PRG4 (2 cases), MALAT1::FN1, PDGFRA::USP35 and TIMP3::ZCCHC7 (1 case each). Three tumors contained more than one fusion (FN1::PRG4 with TIMP3::ZCCHC7, FN1::TEK with FN1::PRG4, and FN1::TEK with MALAT1::FN1). Clinical follow up (17 patients; median follow up duration 38 months; range 4-173 months) showed 13 (76%) to be alive without evidence of disease and 4 (24%) to be alive with persistent/recurrent local disease. No metastases or deaths from disease were observed. We conclude that these unusual tumors represent a distinct category of synoviocytic neoplasia, which we term \"chondroid synoviocytic neoplasm\", rather than simply ordinary TGCT with cartilage. Despite potentially worrisome morphologic features, they appear to behave in at most a locally aggressive fashion.

OBJECTIVE: To investigate the causal relationship between gut microbiota and pigmented villonodular synovitis using Mendelian randomization analysis.
METHODS: We conducted a two-sample Mendelian randomization analysis to investigate the causal relationship between 211 gut microbiome taxa and pigmented villonodular synovitis based on GWAS summary data, with inverse variance weighted (IVW) analysis as the primary result and the other methods as supplementary analyses. The reliability of the results was tested using Cochran\'s Q test, MR-Egger regression, MR-PRESSO method and conditional Mendelian randomization analysis (cML-MA).
RESULTS: The increased abundance of Barnesiella (OR=3.12, 95% CI: 1.15-8.41, P=0.025) and Rumatococcaceae UCG010 (OR=4.03, 95% CI: 1.19-13.68, P=0.025) may increase the risk of pigmented villous nodular synovitis, and elevated abundance of Lachnospiraceae (OR=0.33, 95% CI: 0.12-0.91, P=0.032), Alistipes (OR=0.16, 95% CI: 0.05-0.53, P=0.003), Blautia (OR=0.20, 95% CI: 0.06-0.61, P=0.005), and Lachnospiraceae FCS020 group (OR=0.38, 95% CI: 0.15-0.94, P=0.036) and Ruminococcaceae UCG014 (OR=0.36, 95% CI: 0.14-0.94, P=0.037) were all associated with a reduced risk of pigmented villonodular synovitis, which were supported by the results of sensitivity analyses. Reverse Mendelian randomization analysis did not reveal any inverse causal association.
CONCLUSIONS: Increased abundance of specific intestinal microorganisms is associated with increased or decreased risks of developing hyperpigmented villonodular synovitis, and gut microbiota plays an important role in the pathogenesis of this disease.

BACKGROUND: Pigmented villonodular synovitis (PVNS) is a benign proliferative disorder that affects the synovial joints, bursae, and tendon sheaths. To date, few studies have reported on the treatment of postoperative pain and edema in patients with PVNS. Herein, we present the case of a woman who developed pain and edema in the left lower limb 1 wk after synovectomy and arthroscopic partial meniscectomy and was unable to walk due to limited flexion and extension of the left knee.
METHODS: A 32-year-old woman underwent synovectomy and arthroscopic partial meniscectomy successively and was treated with a combination of manual lymphatic drainage (MLD) and kinesio taping (KT) in our hospital to alleviate postoperative pain and edema. The following parameters were assessed at 2 wk post-treatment and 1 wk post-discharge follow up: suprapatellar circumference, infrapatellar circumference, visual analog scale score, knee range of motion, pittsburgh sleep quality index score, hamilton anxiety rating scale (HAMA) score, and hamilton depression rating scale (HAMD) score. After treatment, the postoperative pain and edema in the patient\'s left knee were effectively relieved, resulting in improved sleep quality and remarkably attenuated HAMA and HAMD scores.
CONCLUSIONS: Combined MLD and KT may be an effective approach for relieving postoperative pain and edema in patients with PVNS.

UNASSIGNED: Pigmented Villonodular Synovitis (PVNS) is a rare disease of osteoskeletal tissue. Cytodiagnosis of PVNS on fine needle aspiration (FNA) smears is therefore rarely reported. The PVNS usually affects the larger joints. The involvement of the smaller joints and bones are uncommon.
UNASSIGNED: The reported case is one such rarity wherein the diagnosis of PVNS was carried out on the FNAC. The case showed the involvement of all carpal bones except for the pisiform. The 2 nd- 5 th metacarpal bases were also found to be involved in the disease process. The presence of sheets of synoviocytes with brown altered hue to the cytoplasm along with multinucleate giant cells and pigmented macrophages were characteristically present in the smears of FNA. The diagnosis was confirmed on the tissue biopsy. The present case is reported for its unusual multiosteotic involvement of wrist joint bones and the metacarpal bones simultaneously with radiological evidence. The cytomorphology of the lesion in the present case were noteworthy as a learning experience in reporting of PVNS of wrist joint on FNA smears.

Pigmented villonodular synovitis (PVNS) is a rare locally aggressive benign tumor in the temporomandibular joint (TMJ). This paper presents a patient with TMJ-PVNS involving masseteric space, temporal bone, zygomatic process, and mandibular ramus. Digital technique was used to determine the boundary of the lesion and reconstruct the normal glenoid fossa. The temporalis myofascial flap was transplanted between titanium mesh and condyle to reconstruct the disk after the complete resection of the tumor. The patient\'s facial profile is symmetrical, with a mouth ope-ning of 43 mm. No local recurrence and complications, such as cerebrospinal fluid fistula and encephaloceles, were detected during 30-month follow-up period.

BACKGROUND: The invasion patterns and long-term outcomes of diffuse tenosynovial giant cell tumor (D-TSGCT) of the ankle joint remain unclear.
METHODS: Seven patients who visited our department between 2011 and 2023 and were diagnosed with D-TSGCT of the ankle joint by contrast-enhanced MRI and a pathological diagnosis were included. The invasion patterns of ankle D-TSGCT on MRI were investigated. The recurrence rate and clinical symptoms were examined in five patients followed up for more than seven years after total resection.
RESULTS: In seven patients (1 male/6 females, mean age 37.0±16.6 years, range 15-57 years) with D-TSGCT of the ankle joint, contrast-enhanced MRI at the initial presentation showed invasion within the ankle joint, extending along the tendon sheath, within the talocalcaneal joint, and in the tarsal sinus in 100% of cases, around the deltoid ligament in 86%, within the plantar surface in 43%, invasion of the interosseous membrane in 57%, around the Achilles tendon in 29%, and scalloping on the talocrural joint in 43%. The mean time from mass awareness to the first visit was 51.9±80.0 months (range 1-240 months). Gross total resection, defined as the removal of all tumors as gauged by MRI, was initially performed on 6/7 patients. One patient underwent partial resection of only the anterior part of the tumor. Of the six cases in which gross total resection was performed, 5 had long-term follow-up of more than seven years post-operatively, and one case is still only one year post-operatively. The long-term results of five patients followed for more than seven years after total resection were as follows: a mean follow-up period of 125 months (range 89-171 months), a 100% recurrence rate, a mean time to recurrence of 27.5±19.2 months (range 7-60 months), and a 16% reoperation rate. In the last follow-up, osteoarthritic changes were observed radiographically in 2/5 patients (40%), both of whom had scalloping of the talocrural joint on MRI at the time of the initial diagnosis. Four of the five patients (80%) had no clinical symptoms in the last follow-up.
CONCLUSIONS: Ankle D-TSGCT presents with a strong local infiltrative pattern inside and outside the ankle joint along the tendon sheath, radical resection may be difficult, and the recurrence rate may be higher than previously reported. On the other hand, there are many cases that remain free of clinical symptoms in the long term after recurrence, and surgical indications for ankle D-TSGCT need to consider function preservation as well as recurrence rates.

Aim: Real-world treatment patterns in tenosynovial giant cell tumor (TGCT) patients remain unknown. Pexidartinib is the only US FDA-approved treatment for TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Objective: To characterize drug utilization and treatment patterns in TGCT patients. Methods: In a retrospective observational study using IQVIA\'s linked prescription and medical claims databases (2018-2021), TGCT patients were stratified by their earliest systemic therapy claim (pexidartinib [N = 82] or non-FDA-approved systemic therapy [N = 263]). Results: TGCT patients treated with pexidartinib versus non-FDA-approved systemic therapies were predominantly female (61 vs 50.6%) and their median age was 47 and 54 years, respectively. Pexidartinib-treated patients had the highest 12-month probability of remaining on treatment (54%); 34.1% of pexidartinib users had dose reduction after their first claim. Conclusion: This study provides new insights into the unmet need, utilization and treatment patterns of systemic therapies for the treatment of TGCT patients.
Treatment patterns in patients with tenosynovial giant cell tumors in the USAThis database study is the first investigation of how drugs are used to treat patients with tenosynovial giant cell tumor (TGCT) in the real world. We researched adult TGCT patients from IQVIA\'s prescription and medical claims databases who started treatment with pexidartinib (N = 82) or other non-US FDA-approved systemic therapies (N = 263). The patients included in this analysis were mostly women (61.0 and 50.6%) and their median age was 47 and 54 years for pexidartinib and other non-FDA-approved systemic therapies, respectively. The patients treated with pexidartinib were most likely to remain on treatment (54.0%) at the end of the first year. Most patients (79.3%) started pexidartinib treatment at a total daily dose of 800 mg/day, as per the product label. Only 34.1% of patients had reduced medication dose during follow-up. Of note, this study found that TGCT patients were treated with other systemic therapies which remain unproven to be safe and effective in medical studies of TGCT. Given the unmet need, and with pexidartinib being the only approved systemic treatment in USA, there is an opportunity for the larger population of adult TGCT patients to benefit from its use. Further research is needed to identify barriers for access to pexidartinib and treatment of TGCT patients.

BACKGROUND: Pigmented villonodular synovitis is a rare yet locally invasive disorder impacting synovial tissues. This case report delineates the atypical manifestation of pigmented villonodular synovitis in the talonavicular joint, detailing its diagnostic complexity and successful management.
METHODS: A 56-year-old Iranian patient with a 4-year history of chronic ankle pain, initially diagnosed with degenerative joint disease post-trauma based on imaging, underwent talonavicular fusion surgery. An unexpected pigmented villonodular synovitis mass was encountered during the procedure. Subsequent interventions encompassed tumor resection, talonavicular joint fusion, and allograft bone grafting. Despite the initial intervention, persistent pain and nonunion necessitated a secondary procedure, involving joint surface curettage and autograft bone grafting. At the 12-month follow-up, the patient remained pain-free without tumor recurrence.
CONCLUSIONS: This case report highlights the significance of considering pigmented villonodular synovitis as a crucial differential diagnosis in chronic ankle pain, even when there is evidence of degenerative joint disease and a history of trauma. Magnetic resonance imaging serves a crucial role in accurate diagnosis. Treatment necessitates precise tumor removal, appropriate bone grafting techniques and secure fixation.
METHODS: IV.

BACKGROUND: Intra-articular synovial hemangioma of the knee is a relatively rare benign tumor that if left undiagnosed and treated may be followed by degenerative cartilaginous changes and osteoarthritis. However, the non-specific symptoms of synovial hemangiomas limit its early diagnosis. We report our encounter with synovial hemangioma of the knee in which the diagnosis was based on a > 20-year history of chronic pain without joint swelling or hematoma.
METHODS: A 34-year-old man with a localized vascular malformation on the upper edge of the left patella presented with pain and a restricted range of motion. CT and MRI revealed a tumorous lesion at this location. Upon excision of the lesion, the patient\'s symptoms disappeared, with no recurrence at the 1-year follow-up.
CONCLUSIONS: Accurate diagnosis and appropriate early treatment are necessary for synovial hemangiomas to forestall articular cartilage degeneration due to recurrent intra-articular hemorrhages.
CONCLUSIONS: Synovial hemangioma should be considered when a patient presents with recurrent knee pain, even in the absence of swelling or episodes of joint effusion.