Pigmented Villonodular Synovitis Research Articles

Pigmented Villonodular Synovitis in a Rare Site

Pigmented villonodular synovitis (PVNS) is a rare locally aggressive benign proliferative growth of the synovium of unknown etiology known to involve the knee (80%), hip (10%), ankle (5%), and exceptionally temporomandibular joint and spine. It poses a diagnostic dilemma when it occurs at the ankle with the clinician tending to overlook it like an ankle sprain or posttraumatic pathology. The optimal treatment is surgery. Malignant change of the lesion, although rare is known for its ability for reactivated growth and a tendency to recur. Postoperative radio synoviorthesis may be required to remove the excess synovium when surgery alone falls short of removing the residual synovial membrane. This article reports the case of a rare localized PVNS of the ankle. Although rare at the ankle, PVNS must neither be mistaken for a malignant lesion nor be neglected as a nonspecific swelling.

Pigmented Villonodular Synovitis of the Wrist Simulating Carpal Tunnel Syndrome

Diffuse pigmented vellonodular synovitis in the wrist region behaving like a carpal tunnel syndrome is rare. The objective of this article is to present a patient with diffuse pigmented vellonodular synovitis of the right wrist simulating a carpal tunnel syndrome resolved with surgical treatment, obtaining optimal results. The patient began with pain in the area of the right wrist, accompanied by paresthetic sensations as well as a diffuse increase in volume in the distal third of the forearm that increased with work activity. During surgery, diffuse proliferation of the synovium of the sheath of the flexor tendons of the fingers was verified, it was resected and sent to Pathology, diagnosing diffuse pigmented vellonodular synovitis. After surgery, the symptoms disappeared with a very satisfactory evolution.

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>

Giant cell tumor of the tenosynovial type in the prevertebral space with a cervical approach

<p class="abstract">The complex anatomy of the neck makes surgical interventions of cervical neoplasms a very complex process. The aforementioned challenges the surgeon to find a surgical approach with the least morbidity and cosmetic sequelae. This is particularly true in tumoral occupation of the prevertebral space (PVS), most frequently due to the extension of neoplasms from naso and oropharynx; whereas primary tumors of the PVS are extremely rare. There are a number of surgical approaches to access the skull base and the anterior region of the upper cervical spine, such as the transcervical-transtemporal approach, retraction and dissection of the soft palate, mandibular osteotomy, medial glossotomy, among others. The following article presents a case report in which a less invasive combined transcervical-transoral approach was performed on a tenosynovial giant cell tumor of the PVS. As an alternative in the treatment of these type of lesions, it is in our opinion equally effective and less morbid.</p>

A New Simple and Practical Clinical Classification for Tenosynovial Giant Cell Tumors of the Knee.

ObjectiveTo propose a simple and practical clinical classification for tenosynovial giant cell tumor (TGCT) of the knee.MethodsA retrospective study was conducted to verify the value and significance of this clinical classification. TGCT growth patterns, knee joint capsule, and bone erosion were applied to establish this novel clinical classification. Seventy‐eight patients who underwent surgery for TGCT from 2008 to 2016 were identified. This novel clinical classification was retrospectively applied to patients' existing classification, and patients with different TGCT types were statistically compared to verify the significance of the clinical classification.ResultsThe clinical classification included three types and four subtypes. Type 1: localized TGCT, Subtype 1a: localized intra‐articular TGCT, Subtype 1b: localized extra‐articular TGCT. Type 2: diffuse TGCT, Subtype 2a: diffuse intra‐articular TGCT with bone normal, Subtype 2b: diffuse intra‐articular TGCT with bone destruction. Type 3: diffuse TGCT across the knee joint capsule. The mean follow‐up time for the 78 patients was 59.6 months. Twenty‐one patients were in Subtype 1a, four were Subtype 1b, 38 were Subtype 2a, seven were Subtype 2b, and eight were Type 3. Oncological results and surgical complications differed significantly (P = 0.000, P = 0.000). The mean Musculoskeletal Tumor Society functional scores differed significantly at 27.8 for Type 1 patients, 22.9 for Type 2 patients, and 17.0 for Type 3 patients (P = 0.000).ConclusionsThis clinical classification can be easily used to evaluate TGCT of all knees prior to surgery or other treatments and can help determine surgical options.

Treatment, recurrence rates and follow-up of Tenosynovial Giant Cell Tumor (TGCT) of the foot and ankle-A systematic review and meta-analysis.

The tenosynovial giant cell tumor (TGCT) is a usually benign lesion which arises from the synovium. It affects joints, tendon sheaths and bursae. The clinical course is often unpredictable, and local recurrences frequently occur. The aim of this study was to describe different treatment options, surgical complications, and to develop a follow-up regime based on a systematic literature review and meta-analysis of foot and ankle lesions. 1284 studies published between 01/1966 and 06/2021 were identified. 25 met the inclusion criteria, with a total of 382 patients. Of these, 212 patients had a diffuse (dTGCT) and 170 a localized (lTGCT) TGCT. Patients with a dTGCT had a mean age of 36.6±8.2 years, and 55% were female. The overall complication rate was 24% in dTGCT, irrespective of the therapeutic procedure; the mean follow-up was 37.9±27.4 months with a recurrence rate of 21%, and recurrences occurred between 3 and 144 months, the vast majority (86%) within the first 5 years following intervention. Patients with a lTGCT had a mean age of 31.2±5.7 years, and 53% were female. Complications occurred in 12%. The mean follow-up was 51.1±24.6 months, the recurrence rate was 7%, and recurrence occurred between 1 and 244 months after intervention. Diffuse TGCTs of the foot and ankle region have a remarkable recurrence rate irrespective of therapeutic procedures, and most lesions reoccurred within 5, with more than half of these in the first 2 years. The lTGCTs are well treatable lesions, with a low recurrence and a moderate complication rate. Based on these findings, we propose a follow-up regime for the dTGCT including a clinical survey and MR imaging 3 months after surgical intervention (baseline), followed by twice-yearly intervals for the first 2 years, yearly intervals up to the fifth year, and further individual follow-up due to the fact that recurrences can even occur for years later. For the lTGCT a clinical survey and MRT is proposed after 3-6 months after intervention (baseline), followed by annual clinical examination for 3 years, and in case of symptoms MR-imaging. Larger prospective multi-center studies are necessary to confirm these results and recommendations.

Neoplastic synovial lining cells that coexpress podoplanin and CD90 overproduce CSF-1, driving tenosynovial giant cell tumor.

Tenosynovial giant cell tumor (TCGT) is a rare neoplasm affecting the synovium of joints, bursae, and tendon sheaths. The overproduction of colony-stimulating factor-1 (CSF-1) by a minority of the tumor population works in a paracrine fashion to drive tumor growth. Pathology of the reactive, monocytic component has been well elucidated, whereas the populations of neoplastic cells and all the sources of CSF-1 overproduction are incompletely characterized. Podoplanin (PDPN), or gp38, is a cell surface glycoprotein that is expressed on fibroblast-like synovial cells and upregulated in rheumatoid arthritis and many cancers; it governs cell mobility, epithelial-mesenchymal transition, and other functions and is associated with lymphangiogenesis and poor prognosis in many solid tumors, which underscores its local and possible systemic effects. We found higher PDPN expression in TGCT than in internal controls of patients' healthy synovium. Flow cytometry partitioned PDPNhigh cells into PDPNhigh CD90+ and PDPNhigh CD14+ populations. Quantitative real-time polymerase chain reaction analysis of the PDPNhigh CD90+ cells revealed that CSF-1 expression was 10-fold higher than in PDPNhigh CD14+ cells. Therefore, we conclude that the lining fibroblast-like synovial cells, which express PDPNhigh CD90+ , are responsible for the overproduction of CSF-1 and for driving tumor growth.

Arthroscopic Versus Open Management of Diffuse-Type Tenosynovial Giant Cell Tumor of the Knee: A Meta-analysis of Retrospective Cohort Studies.

Background:Whether arthroscopic or open surgical management for diffuse-type tenosynovial giant cell tumor (D-TGCT) of the knee is associated with a lower rate of recurrence is unknown.Methods:PubMed, Scopus, Web of Science, Cochrane, and EMBASE were searched on December 3, 2020. Retrospective studies that reported on recurrence rates for arthroscopic versus open management of D-TGCT were included. A total of 16 studies evaluating 1143 patients with D-TGCT of the knee were included (nopen = 551, narthroscopic = 350 patients, and narthroscopic/open = 23 patients). Random-effects meta-analyses were used to summarize and compare the reported recurrence rates, stratified by approach and overall recurrence. The meta-analysis was registered with PROSPERO.Results:The recurrence rate per year (incidence) for arthroscopic procedures was 0.11 (95% CI 0.08 to 0.16, P < 0.0001) and for open procedures was 0.07 (95% CI 0.04 to 0.13, P < 0.0001). There was a 1.56 times (95% CI 1.04 to 2.34, P = 0.0332) increased risk of recurrence when treating D-TGCT of the knee with an arthroscopic approach. When evaluating only the subset of studies that had data for both arthroscopic and open approaches, the incidence rate per year for arthroscopic procedures was 0.17 (95% CI 0.11 to 0.27, P < 0.0001) and for open procedures was 0.11 (95% CI 0.06 to 0.19, P < 0.0001). The rate of overall complications was 0.04 (95% CI 0.01 to 0.08, P < 0.0001).Conclusion:Arthroscopic surgical management of D-TGCT of the knee in our study resulted in a 1.56 times risk of recurrence as compared with the open approach. The percent of overall complications was minimal.

Diffuse pigmented villonodular synovitis of the elbow.

Diffuse pigmented villonodular synovitis of the elbow.

PVNS Of The Knee: A Consecutive Series of 53 Patients Treated Either Arthroscopically or With Open Synovectomy

Pigmented villonodular synovitis (PVNS) is a subtype of tenosynovial giant cell tumor. Such tumors are rare and locally aggressive, though benign, with an average annual incidence between 1.8 and 9.2 cases per million in the U.S. [1] This low incidence of disease makes clinical trials difficult to conduct. Clinically, PVNS is separated into localized (LPVNS) and diffuse (DPVNS) disease. Surgical options include open, arthroscopic and combination arthroscopic/ open approaches for disease involving both anterior and posterior compartments of a joint. Despite surgical resection being the most common treatment modality for PVNS, recent medications have been developed targeting the colony stimulating factor 1 receptor (CSF1R) pathway.[2] In our case series, we selected 53 patients meeting inclusion criteria and treated between 2002-2019

Outcomes of arthroscopic management for pigmented villonodular synovitis of the hip.

Early synovectomy is considered as the main treatment of pigmented villonodular synovitis (PVNS) of the hip in young patients with preserved cartilage. The purpose of the study is to evaluate outcomes of arthroscopic management for PVNS of the hip. Patients who underwent primary hip arthroscopy for the treatment of histology-confirmed PVNS by the senior author between January 2012 and December 2016 were retrospectively reviewed. We excluded patients who had less than 1-year follow-up or had undergone primary surgeries with other surgeons and then received revision hip arthroscopic procedures by the senior author. The recurrence of PVNS and postoperative condition of affected hip were assessed by follow-up magnetic resonance imaging (MRI). Patient-reported outcomes of modified Harris hip score (mHHS) and 12-item International Hip Outcome Tool (iHOT-12) were collected at latest follow-up. Nine patients (2 males, 7 females) with a mean age of 24.3 ± 11.2years (range 14-44years) were included in this study. Localized PVNS was observed in four patients, and diffuse PVNS was observed in five patients. No patient presented with advanced osteochondral destruction. Five patients received single adjuvant radiosynoviorthesis. No patient had evidence of recurrence based on follow-up MRI. Patient-reported outcomes were obtained in eight patients at mean 55.8 ± 26.1months (range 24-84months) after the index surgery. The mean mHHS was 94.6 ± 4.9 (range 84.7-100) and the mean iHOT-12 was 93.3 ± 20.2 (range 50-120). No patient needed secondary surgery during the follow-up period. Arthroscopic subtotal synovectomy can offer favorable short to mid-term outcomes in the treatment of hip PVNS in case of no advanced osteochondral damage at presentation.

Mimics of Erdheim–Chester disease

Erdheim-Chester disease (ECD) is a rare histiocytic neoplasm with frequent multiorgan involvement. An accurate diagnosis of ECD requires the correlation of clinical features, histopathologic and radiologic findings. We describe a case series of patients with a referral diagnosis of ECD, whereby the diagnosis was changed to non-histiocytic diseases after comprehensive review at a tertiary care center. This accurate revision of the referral diagnosis of ECD enabled initiation of proper disease-directed therapy in a timely manner for these patients and avoided unnecessary exposure to systemic cytotoxic chemotherapy or targeted agents. Our study highlights the value of a multidisciplinary team of histiocytosis experts in confirming the diagnosis of ECD and also brings attention to other conditions to consider that can mimic ECD, including osteopoikilosis, tenosynovial giant cell tumour, IgG4-related disease, fibrous dysplasia and chronic recurrent multifocal osteomyelitis.

Is intra-articular infliximab therapy a good alternative to radionuclide synovectomy for a patient with refractory pigmented villonodular synovitis?

Pigmented villonodular synovitis (PVNS) is a rare disease that has clinical and histopathological characteristics of both benign proliferative disorder and a chronic inflammatory process of the synovial tissue. The primary mode of treatment is surgery followed by an adjuvant radiotherapy; however, the risk of recurrence is a significant (40–70%). Several publications suggest that the TNF-α inhibitors might be a treatment option. We present a case of a 29-year-old female diagnosed with PVNS of the knee joint, refractory to surgery and 3 radionuclide synovectomies. Because the possibilities of conventional therapy were exhausted, treatment with an intra-articular anti-TNF-α monoclonal antibody (infliximab) was performed. Despite a high safety profile and a good tolerance of that therapy we did not observe significant clinical and radiological improvement. To assess the effectiveness of intra-articular TNF-α inhibitors as an adjuvant treatment in PVNS, prospective studies are needed.

Selected Articles from This Issue

Colony stimulating factor 1 receptor (CSF1R)-dependent cells in the microenvironment (such as macrophages and osteoclasts) contribute to angiogenesis, tumor growth, metastasis, and bone degradation. In this First Disclosure, Smith and colleagues present the characterization of vimseltinib, a selective oral inhibitor of CSF1R in tenosynovial giant cell tumor (TGCT). Vimseltinib depleted macrophages and CSF1R-dependent cells and inhibited tumor growth in preclinical studies. Clinically, the authors present three patients whose CSF1R biomarkers and tumor burden were reduced. Their data supports the continued clinical development of vimseltinib for TGCT.The triple-negative subtyp. of breast cancer (TNBC) carries the highest rate of parenchymal brain metastasis (BrM) and leptomeningeal metastasis (LM). In this manuscript, Deng and colleagues disclose the nitrogen mustard-based compound QBS10072S. QBS10072S delayed tumor growth and reduced leptomeningeal dissemination in a preclinical brain metastasis model. Interestingly, the compound was able to target micro-metastases, which remains a difficult aspect of detecting and treating LM. As the compound was well-tolerated, the continued development of QBS10072S for TNBC LM patients is warranted.Brain metastases occur in approximately 30% of NSCLC patients, leading to significantly worse prognosis. Stereotactic radiotherapy and/or whole brain radiotherapy is currently standard of care for these patients. To increase the effectiveness of radiation therapy in NSCLC brain metastases, Baschnagel and colleagues administered the ATP-competitive ATR inhibitor M6620. M6620 radiosensitized patient-derived xenografts in mice by inhibiting pChk1 and reducing DNA double-strand break (DSB) repair. Ultimately, this resulted in longer overall survival in the preclinical model. Their results support the ongoing phase I clinical study of M6620 in combination with whole brain irradiation (NCT02589522).Adenosine acts as an immunosuppressor by suppressing T cells and dendritic cells and stimulating regulatory T cells. Adenosine is generated in the tumor microenvironment by CD73 from AMP released by cell turnover. In this study, Wurm and colleagues generate a humanized antagonistic CD73 antibody, mAb19. Combining mAb19 with PD-1 inhibition increased T cell activation in vitro. They also demonstrate the combination of mAb19 with the adenosine receptor agonist ADORA3 and doxorubicin, which is known to increase adenosine levels. mAb19 therefore inhibits immunosuppression from the adenosine pathway and is suited for continued development as a cotherapy with immune-targeted or chemotherapy.

Results from Phase I Extension Study Assessing Pexidartinib Treatment in Six Cohorts with Solid Tumors including TGCT, and Abnormal CSF1 Transcripts in TGCT.

To assess the response to pexidartinib treatment in six cohorts of adult patients with advanced, incurable solid tumors associated with colony-stimulating factor 1 receptor (CSF1R) and/or KIT proto-oncogene receptor tyrosine kinase activity. From this two-part phase I, multicenter study, pexidartinib, a small-molecule tyrosine kinase inhibitor that targets CSF1R, KIT, and FMS-like tyrosine kinase 3 (FLT3), was evaluated in six adult patient cohorts (part 2, extension) with advanced solid tumors associated with dysregulated CSF1R. Adverse events, pharmacokinetics, and tumor responses were assessed for all patients; patients with tenosynovial giant cell tumor (TGCT) were also evaluated for tumor volume score (TVS) and patient-reported outcomes (PRO). CSF1 transcripts and gene expression were explored in TGCT biopsies. Ninety-one patients were treated: TGCT patients (n = 39) had a median treatment duration of 511 days, while other solid tumor patients (n = 52) had a median treatment duration of 56 days. TGCT patients had response rates of 62% (RECIST 1.1) and 56% (TVS) for the full analysis set. PRO assessments for pain showed improvement in patient symptoms, and 76% (19/25) of TGCT tissue biopsy specimens showed evidence of abnormal CSF1 transcripts. Pexidartinib treatment of TGCT resulted in tumor regression and symptomatic benefit in most patients. Pexidartinib toxicity was manageable over the entire study. These results offer insight into outcome patterns in cancers whose biology suggests use of a CSF1R inhibitor. Pexidartinib results in tumor regression in TGCT patients, providing prolonged control with an acceptable safety profile.

Grading System and Surgical Strategy for Temporal Bone Diffuse-Type Tenosynovial Giant Cell Tumor.

To develop a novel grading system and appropriate surgical approaches for patients with diffuse type tensosynovial giant cell tumor (D-TGCT) of the temporal bone. Retrospective cohort study. We retrospectively reviewed 31 patients with temporal bone D-TGCT between June 2012 and July 2021. All patients underwent comprehensive clinical evaluations, including clinical presentations, hearing threshold, imaging studies, surgical approaches, and prognosis. A grading system was developed based on the tumor location and adjacent neurovascular structures involvement according to imaging and intraoperative findings. In this study, grade II tumors were the most common (13/31), followed by grades I (7/31), III (7/31), and IV (4/31) tumors. Seven grade I patients received the subtemporal middle cranial fossa approach (SMCF) combined with the canal wall up mastoidectomy and tympanoplasty (CWUT). Nine grade II patients underwent SMCF combined with subtotal petrosectomy (SPTR), and four grade II patients underwent SMCF combined with CWUT. Seven grade III patients received SMCF combined with SPTR and dura mater reconstruction, and four grade IV patients underwent infratemporal fossa approach type B. Gross total resection was achieved in all patients, and the median follow-up time was 30.1 months (range, 4-96 months). Three patients (one grade II, one grade III, and one grade IV) had recurrence during follow-up, and the patient with grade III tumor had two recurrences. Gross total resection is the first-line treatment for patients with D-TGCT of the temporal bone. This novel grading system enables surgeons to select optimal surgical strategy. Long-term follow-up is mandatory postoperatively. 4 Laryngoscope, 132:1275-1284, 2022.

Tuberculosis of the knee masquerading as pigmented villonodular synovitis: Report of two cases.

Introduction and importanceThe manifestation of tuberculous mimicry is challenging to diagnose, especially in extrapulmonary Tuberculosis (TB). Pigmented villonodular synovitis (PVNS) may mimic tuberculous arthritis of the knee joint. In young, otherwise healthy-appearing individuals, tuberculous arthritis and PVNS in the knee joint could present as monoarticular involvement, with painful swelling of extended duration and limited movement. The core therapies for tuberculous arthritis and PVNS are different.Case presentationThere are two patients. First, male 25 years old presented with a painful mass at the left knee of 3-years duration. The second patient was 14 years old boy who presented with a painful mass at his left knee for ten months before being admitted to the hospital. From the physical examination, plain x-ray, and MRI, both patients are highly suggestive of PVNS. However, the histopathology result and microbial culture showed a tuberculous-specific process.Clinical discussionBecause of its clinical manifestations, X-ray, and MRI features, patients were initially suspected of having the diffuse type of PVNS. An improper diagnosis may be due to atypical clinical presentation, wide use of antibiotics, the low specificity of diagnostic tools, and most of all, the clinician not prioritizing the possibility of tuberculous arthritis. Open biopsy and the result of the microbial culture establish the definitive diagnosis of knee tuberculosis.ConclusionIn conclusion, the clinical and radiologic findings in TB gonitis and PVNS are occasionally similar. Therefore TB gonitis should be highly suspicious, especially in endemic areas. Histopathology results and mycobacterial culture need to determine the diagnosis.

O12 A rare mimic of inflammatory arthritis

Case report - IntroductionMelorheostosis is a very rare benign bone disorder involving sclerosing hyperostosis. The name derives from the Greek terms Melos ‘limb’, rheos ‘flow’ and osteon ‘bone’. The incidence of melorheostosis is 0.9 cases per million population, and in the majority of cases is diagnosed before the age of 20 years. It presents with pain, deformities, limitations of a range of motion, contractures, muscle atrophy, and limb swelling. We present a case of a 33-year-old lady who was referred with a history of pain and swelling of the right knee.Case report - Case descriptionThis 33-year-old lady of Nigerian origin was referred to the rheumatology department with a 7-year history of fluctuating pain and swelling in the right knee with the possibility of inflammatory arthritis. Prior to this, she had been seen by the local orthopaedic team with subsequent input sought from the regional specialist orthopaedic bone unit in Birmingham. The synovial biopsies did not show any evidence of inflammation or pigmented villo-nodular synovitis (PVNS). Prior to moving to the UK, she had been assessed in Germany and Dubai due to knee pain and swelling with a diagnosis of the unclear bone-related condition and fibromyalgia. Clinically the right knee had a chronic cool swelling with reduced range of movement but no synovitis and no signs of inflammatory arthritis in other joints. There were no features of seronegative inflammatory arthritis or connective tissue diseases. Investigations showed weak positive ANA with normal CRP, bone profile, FBC, urea and electrolytes, with negative rheumatoid factor and anti-CCP antibody. X-ray knee arranged, showed a flowing periosteal thickening medial cortices of the femur and tibia consistent with ‘melorheostosis’. MRI right knee also confirmed the same diagnosis. Imaging of the upper limbs, spine and pelvis showed no involvement. Input from the metabolic bone health team was arranged who did not deem bisphosphonates useful in her case. Physiotherapy input was arranged to improve her leg posture and movements along with appropriate patient education and analgesia titration.Case report - DiscussionWe present a rare mimic of inflammatory arthritis. Initially referred by GP to orthopaedic team who considered PVNS which was ruled out by biopsies, then next question was about inflammatory arthritis due to recurrent history of knee pain and swelling which is valid differential for monoarthritis. Rheumatology assessment noted a puffy knee but no effusion to aspirate, x-ray imaging was diagnostic for melorheostosis due to the typical presence of ‘dripping wax appearance’. As rheumatologists while assessing joints, genetic and metabolic causes need to be considered besides inflammatory and infective causes. A thorough history remains essential along with interaction with radiology colleagues which is the main learning point. Case report - Key learning pointsNon-inflammatory conditions like melorheostosis can mimic inflammatory arthritisSimple imaging like X-rays and discussion with radiology colleagues are often underrated.

Exposure-response analysis of efficacy and safety for pexidartinib in patients with tenosynovial giant cell tumor.

This analysis was conducted to assess exposure–response relationships for efficacy and safety of pexidartinib in patients with tenosynovial giant cell tumor. Efficacy was assessed categorically by overall response rate (ORR) with Response Evaluation Criteria in Solid Tumors version 1.1 and longitudinally (changes in tumor size and volume). Safety included hepatic parameters (i.e., alanine aminotransferase [ALT], aspartate aminotransferase [AST], and total bilirubin). Average pexidartinib concentration (Cavg) was identified as the primary exposure parameter correlated with response. In categorical and longitudinal analyses, higher Cavg coincided with greater ORR and tumor size reduction, respectively, with smaller joint size having a greater impact. For safety, a significant relationship was observed between Cavg and incidence of ALT‐related and AST‐related adverse events (AEs). With increased exposure, an increase in efficacy was predicted with near maximum effect at 800 mg/day. Higher initial dose (1000 mg/day) during the first 2 weeks did not improve efficacy. Higher doses were associated with an increased risk of ALT‐related and AST‐related AEs. These results support the US Food and Drug Administration–approved dose (400 mg two times/day without initial loading dose).

Clinical outcomes of diffuse PVNS of the knee following arthroscopic complete synovectomy±posterior open resection

IntroductionThis study compares recurrence rates and functional outcomes of patients who underwent anterior arthroscopic synovectomy versus combined anterior arthroscopic/posterior open synovectomy for diffuse pigmented villonodular synovitis (DPVNS). Methods41 patients were grouped by initial procedure and tracked for disease recurrence and functional outcomes (Lysholm Scale). Results24 patients (58.5%) had disease recurrence [16 (57.1%) arthroscopic, 8 (61.5%) combined, chi-square test p = 0.81]. The combined procedure mean Lysholm Score (75.4) exceeded the arthroscopic (68.1) (two-sample t-test p = 0.25). ConclusionsThere is no statistical evidence that the combined procedure harms functionality more than arthroscopic only or that recurrence rates differ between treatment methods.