A molecular study of synovial chondromatosis.

Synovial chondromatosis (SC) is a rare benign cartilaginous neoplasm in which recurrent fibronectin 1 (FN1) and activin receptor 2A (ACVR2A) gene rearrangements have been recently reported. Triggered by a case of malignant transformation in SC (synovial chondrosarcoma) showing a novel KMT2A-BCOR gene fusion by targeted RNA sequencing, we sought to evaluate the molecular abnormalities in a cohort of 27 SC cases using a combined methodology of fluorescence in situ hybridization (FISH) and/or targeted RNA sequencing. Results showed that FN1 and /or ACVR2A gene rearrangements were noted in 18 cases (67%), with an FN1-ACVR2A fusion being confirmed in 15 (56%) cases. Two cases showed only FN1 gene rearrangement, without other abnormalities. A novel FN1-NFATc2 gene fusion was noted in one case by RNA sequencing. The remaining nine cases showed no abnormalities in FN1 and ACVR2A genes. No additional cases showed BCOR gene alterations. In conclusion, this study confirms that FN1-ACVR2A fusion is the leading pathogenetic event in SC, at even higher frequency than previously reported. FISH methodology emerges as an appropriate tool in the identification of FN1 and ACVR2A gene abnormalities, which can be used in challenging cases. Further studies are needed to determine the recurrent potential of BCOR abnormalities in this disease.

Scanning electoronmicroscopical analysis of the loose bodies of synovial chondoromatosis in temporomandibular joint.

The aim of this study is to reveal the morphological property about the loose bodies (LBs) of temporomandibular joint (TMJ) by scanning electron microscope (SEM). We obtained specimens from two female cases of released loose body by surgical operation. These specimens were fixed by soaking in a mixture of 5% glutaraldehyde or 4% formaldehyde for one week. They were cut into half pieces. These specimens were observed at an accelerating voltage of 3 kV under a SEM (JSM-5500, JEOL, Tokyo). In the electron microscopic findings, it seems to be separated into two different parts as inside part and outside part. On the inside part, collagen fibers were running very densely in the same direction in an orderly neatly manner. Whereas, we observed waved collagen fibers running irregularly with many spaces on the outside part. Outside part seems to be porous pattern compared with inside part. It might be that the surface and outside part included many active fibroblasts. As results, it seems that the LBs might develop in a multi-layer style, in which fibrous tissues were piled up loosely around the inside part. The proliferating activity of LBs grows from the inside to outside of SC in TMJ.

Huge Bursitis and Bursal Synovial Osteochondromatosis Associated With Scapular Osteochondroma Mimicking a Giant Calcific Mass of the Chest Wall.

Osteochondroma is the most common benign bone tumor, but it rarely arises from the scapula. Scapulothoracic bursitis is quite rare and osteochondroma is one of the unusual causes of this condition. Synovial chondromatosis may occur extremely uncommonly in this bursa. We reported an unusual case of scapulothoracic bursitis with synovial chondromatosis, which is caused by osteochondroma. To the best of our knowledge, there is no defined chondromatosis in the scapulothoracic bursa secondary to scapular osteochondroma in the literature.

Role of synovium-derived fibrous cartilage in temporomandibular joint synovial chondromatosis.

BACKGROUND: Synovial chondromatosis (SC) of temporomandibular joint (TMJ) occupies 3% SC cases. In other joints like hip and knee which were composed hyaline cartilage (HC), loose bodies (LBs) were reported to be a HC feature. However, condyle surface and disc in TMJ are fibrous cartilage (FC). Therefore, we proposed a different pathogenesis of TMJSC. METHODS: LBs and synovium were collected from seven TMJSC patients, and histological and immunohistological examinations were performed. RESULTS: Three ways of HC formation were discovered: regular-shaped cartilaginous nodules (CNs) in sublining layer (SL) of vascularized synovium, regional chondrification of SL, and finger-like tissue with a tail attaching to synovium. Detached LBs could fuse and were only positively stained by aggrecan. Without synovium attachment to LBs, fused LBs remained a hyaline extracellular matrix (ECM). However, after synovium attachment, transformation from HC to FC occurred. Two types of FC were observed. First type FC was featured by vertical-distributed type I collagen fibers imbedding few chondrocytes, suggesting mature phase with superior mechanical features. Second type FC was featured by medium-density chondrocytes with type I collagen and aggrecan-positive ECM, suggesting primary phase. The transformation process started in appearance of 2nd type FC deriving from synovium covering LB, and gradually replaced HC from periphery to center. CONCLUSIONS: Three ways of HC formation were closely related. Different with SC in other joints, hyaline ECM in LBs of TMJSC could be replaced by FC deriving from synovium, during which 2nd type FC first replaced HC and then transformed to 1st type FC.

Synovial chondromatosis of the temporomandibular joint: Immunohistochemical examinations regarding the role of insulin-like growth factors and their binding proteins in the etiology of this disease.

Synovial chondromatosis (SC) is a benign disease of the joints without a known cause. It sometimes affects the temporomandibular joint (TMJ) and is accompanied by pain, swelling, malocclusion, and crepitation. It has been divided into three stages by Milgram and is supposed to originate from the synovia and cartilage of a joint (Milgram, 1977b). The aim of this study was to examine an involvement of the insulin-like growth factors (IGF-I/-II) and their binding proteins (IGFBP-1 to -6) in the etiology of this disease. Therefore 23 specimen of SC from 16 patients were immunohistochemically stained and microscopically examined. Staining was assessed semiquantitatively: negative (-), weakly positive ((+)), moderately positive (+), strongly positive (++) and very strongly positive (+++). It could be seen that especially the chondro- and fibrocytes and the synovia showed positive staining for almost all IGFs and IGFBPs. The underlying tissue, consisting of connective tissue or chondroid matrix, was stained as well but more weakly so. We conclude that the IGF/IGFBP system seems to contribute to the pathogenesis of SC, especially IGF-I and -II, and their effects enhancing binding protein 5.

Relapsing Polychondritis Concomitant With Synovial Chondromatosis of the Temporomandibular Joint.

Relapsing polychondritis (RP) is a rare, multisystem autoimmune disease characterized by inflammation, structural damage, and impaired function of cartilaginous tissues throughout the body. In the craniofacial region, this rare disease has been reported to affect structures of the ear and nose; however, reports of temporomandibular joint (TMJ) involvement are scarce. A second uncommon disorder of cartilage is synovial chondromatosis (SC), a progressive and proliferative disorder of the synovial membrane associated with the formation of variably sized cartilaginous and calcified loose bodies, often causing dysfunction of the joints and enlargement of the joint capsule. It commonly affects the larger joints; TMJ involvement is uncommon. We present the case of a 45-year-old woman with previously diagnosed RP in whom right TMJ pathology subsequently developed, undergoing arthroscopy and biopsy followed by arthroplasty, which was proved to be SC, likely due to her autoimmune disease. To our knowledge, this is the first case describing concomitant SC of the TMJ presumably from pre-existing RP.

OSTEOCHONDROMA OF THE PROXIMAL HUMERUS WITH FRICTIONAL BURSITIS AND SECONDARY SYNOVIAL OSTEOCHONDROMATOSIS.

We report a case of multiple hereditary exostosis in a 33-year old patient with clinical symptoms of pain and impression of a growing mass of the left shoulder alerting potential risk of malignant transformation of an osteochondroma. Imaging studies illustrated perilesional bursitis surrounding an osteochondroma of the proximal humerus. Malignant transformation was excluded with MRI. Fragments of the osteochondroma were dislocated in the inflammatory synovial bursa illustrating a case of secondary synovial osteochondromatosis.

Secondary synovial chondromatosis of the shoulder.

Synovial chondromatosis is classified as either primary or secondary. Primary synovial chondromatosis results from a proliferation of chondrocytes in the synovial membrane leading to the formation of cartilaginous loose bodies. Secondary synovial chondromatosis is a rare condition characterized by the growth of separated particles from the articular cartilage or osteophytes in joint diseases. The present article aims to report the secondary chondromatosis of the shoulder and to discuss the clinical manifestations, pathogenesis, diagnosis, histological findings and management of this condition.

Synovial chondromatosis of pes anserine bursa secondary to osteochondroma.

Osteochondromas are common benign bone tumors. Synovial chondromatosis is a benign cartilaginous metaplasia that occurs in the synovium. The authors describe a unique case of synovial chondromatosis developing in the pes anserine bursa secondary to an underlying osteochondroma of the proximal medial tibia. It is unusual to see both of these processes occurring simultaneously in 1 location. After appropriate consent was obtained, the patient's case was reviewed. A 17-year-old boy presented with a painless mass in the medial aspect of the right leg. Initial imaging of the right leg showed a cartilaginous-appearing lesion arising from the tibia and several distinct additional cartilaginous masses in the adjacent soft tissue. After 16 months of observation, the patient began to have increasing pain in the region of the lesion. The patient underwent surgery for excision of suspected synovial chondromatosis of the right pes anserine bursa and osteochondroma of the proximal right tibia. Postoperatively, the patient had complete resolution of symptoms and regained full range of motion of the knee. He returned to full activities, including walking and running. Osteochondromas are common benign bone tumors. Synovial chondromatosis is a benign synovial metaplastic cartilaginous proliferation that occurs primarily in joints, but can occur in any synovial-lined space. In this case report, the authors describe a unique occurrence of both of these lesions simultaneously. The treatment was excision of the osteochondroma and resection of the chondromatosis lesions, which resulted in an excellent outcome.

Synovial chondromatosis of the cervical spine: a case report and review of the literature.

Synovial chondromatosis is a benign condition characterized by metaplastic changes of the synovial membrane typically affecting large joints. Cervical spine involvement is rare and has not been reported in a teenager. The authors report a case of cervical synovial chondromatosis in a 19-year-old male presenting with left-sided weakness and numbness from spinal cord compression. After gross total resection was accomplished via laminoplasty, the patient's presenting symptoms improved and continued to do so over the follow-up period. The likely cause of the synovial chondromatosis in this patient was repetitive neck trauma as a child from a motor vehicle accident and football. This case demonstrates that the pathophysiology of this rare entity can initiate in the pediatric population. Although rare, synovial chondromatosis should be considered in the differential diagnosis of calcified extradural masses in the teenage population.

Bursal synovial chondromatosis formation following osteochondroma resection.

Osteochondroma is a common tumor of the bone and can be complicated by adventitial bursa formation and malignant transformation of the cartilaginous cap. Synovial chondromatosis formation within these bursae is extremely rare and can be confused with malignant transformation of the osteochondroma cap to a chondrosarcoma. We describe a case of extra-articular synovial chondromatosis formation several years following osteochondroma resection. Cartilage nodule formation within the bursal synovial lining and proliferation of cartilage debris shed from the cartilaginous cap during surgery or biopsy are potential etiologies of this rare complication of osteochondromas.

Unusual cases of elbow locking due to synovial cysts: a report of two cases.

Sudden and intermittent locking of the elbow joint is a com- mon complaint among patients who commonly demonstrate degenerative changes in the elbow. Common causes of elbow locking include acute trauma, osteochondritis dessicans, synovial chondromatosis, and osteoarthritis. Two cases involving patients with symptoms of elbow locking secondary to reasons other than loose bodies within the joint are presented: a synovial cyst within the posterior aspect of the elbow, specifically within the olecranon fossa causing their painful symptoms of locking. These cases present unique features in the diagnostic approaches of elbow locking due to the unexpected association with synovial cysts. We believe that these findings can shed new light on the pathogenesis of this disease.

Fibroblast growth factor 2 involved in the pathogenesis of synovial chondromatosis of temporomandibular joint.

BACKGROUND: Synovial chondromatosis (SC) of temporomandibular joint (TMJ) is a rare proliferative disorder characterized by the formation of cartilaginous or osteocartilaginous nodules in synovium and joint space. Fibroblast growth factor 2 (FGF-2) is frequently applied in chondrogenic differentiation assays. Therefore, we hypothesized that FGF-2 might involved in the pathogenesis of SC. METHODS: SC synovium and loose bodies (LBs) specimens were observed by histological and immunohistochemical methods. Real-time PCR was conducted for comparing genes expressions in SC and normal synovium. SC synoviocytes were stimulated by FGF-2 in the presence or absence of its antagonist long pentraxin-3 (PTX3) for 6 days. Real-time PCR and alkaline phosphatase (ALP) activity were performed to examine the effects exerted by FGF-2 and PTX3. RESULTS: SC synovium, no matter facing the articular cavity or covering LB, was characterized by increased quantity of synoviocytes and blood vessels. FGF-2 was expressed in chondrocytes and fibroblast-like cells of LBs, and the wall of blood vessels. Expressions of chondrogenic genes (Sox9 and Wnt-4), osteogenic genes (Foxc2), FGF-2, and VEGF-A mRNA were significantly higher in SC synovium than that of the control group. The stimulation of FGF-2 on SC synoviocytes increased ALP activity and expressions of chondrogenic genes (Sox9, Col2α1, and Aggrecan), osteogenic genes (Foxc2, osteocalcin, and Col1α1), and VEGF-A, but PTX3 inhibited these effects. CONCLUSION: FGF-2 was responsible for the formation of cartilaginous loose bodies and involved in the pathogenesis of SC.

Secondary synovial osteochondromatosis of the ankle in a child.

We describe a case of a large intra-articular ossifying mass of the ankle joint in a 12-year-old boy who sustained a severe ankle twisting injury at 6 years of age. The mass is presumed to be the result of secondary synovial osteochondromatosis originated from a fractured osteochondral fragment of the medial tubercle of the posterior process of the talus. The mass could be differentiated from os trigonum syndrome, Trevor disease and primary synovial osteochondromatosis based on its location, size and radiologic and histological features.

[Synovial chondromatosis of the temporomandibular joint. A systematic review of the literature on its characteristics]. / Synoviale chondromatose van het temporomandibulaire gewricht. Een systematisch literatuuronderzoek naar de kenmerken.

Synovial chondromatosis of the temporomandibular joint is a disease which occurs rarely. A systematic review of the literature was carried out to identify its demographical, etiological, radiological, and clinical characteristics. A total of 191 case presentations were discovered. The mean age of patients was 47. The disease has been identified more frequently in women than in men. A part from pre-auricular swelling, the most frequently reported clinical characteristics resembled those of temporomandibular disorders. Abnormalities on radiographs were often evident. Insufficient evidence was found that trauma or rheumatoid arthritis plays a role in the development of this disease. Given the similarities with temporomandibular disorders, synovial chondromatosis should be considered in the differential diagnosis of patients suffering from complaints of temporomandibular dysfunction.

Temporomandibular joint synovial chondromatosis with a traumatic etiology.

Synovial chondromatosis (SC) is a metaplastic disorder characterized by the formation of cartilaginous nodules inside the articular space. SC is uncommon in the temporomandibular joint (TMJ). A few reports suggest a correlation between a traumatic episode and the development of SC. The authors describe the diagnosis, treatment and follow-up of a patient with unilateral SC of the left TMJ in conjunction with bony resorption on the mandibular condyle and a clear traumatic etiology. They review and comment on previous reports in the literature.

[Secondary synovial chondromatosis of the ankle joint]. / Sekundäre synoviale Chondromatose des oberen Sprunggelenks.

Synovial chondromatosis of the ankle is a rare condition, particularly secondary chondromatosis. In view of a possible traumatic pathogenesis, chondromatosis should be kept in mind in daily trauma and orthopedics practice. Diagnostic imaging gives a first indication. The key to differentiating between the primary and secondary forms is histological identification. This case shows the necessity of exact differentiation, even in cases of a causal link with a specific injury.

Gene delivery of TGF-ß1 induces arthrofibrosis and chondrometaplasia of synovium in vivo.

To understand the cellular and molecular events contributing to arthrofibrosis, we used an adenovirus to deliver and overexpress transforming growth factor-beta 1 (TGF-ß1) cDNA (Ad.TGF-ß1) in the knee joints of immunocompromised rats. Following delivery, animals were killed periodically, and joint tissues were examined macroscopically and histologically. PCR-array was used to assay alterations in expression patterns of extracellular matrix (ECM)-associated genes. By days 5 and 10, TGF-ß1 induced an increase in knee diameter and complete encasement of joints in dense scar-like tissue, locking joints at 90° of flexion. Histologically, massive proliferation of synovial fibroblasts was seen, followed by their differentiation into myofibroblasts. The fibrotic tissue displaced the normal architecture of the joint capsule and fused with articular cartilage. RNA expression profiles showed high levels of transcription of numerous MMPs, matricellular and ECM proteins. By day 30, the phenotype of the fibrotic tissue had undergone chondrometaplasia, indicated by cellular morphology, matrix composition and >100-fold increases in expression of collagen type II and cartilage link protein. Pre-labeling of articular cells by injection with recombinant lentivirus containing eGFP cDNA showed fibrotic/cartilaginous tissues appeared to arise almost entirely from local proliferation and differentiation of resident fibroblasts. Altogether, these results indicate that TGF-ß1 is a potent inducer of arthrofibrosis, and illustrate the proliferative potential and plasticity of articular fibroblasts. They suggest the mechanisms causing arthrofibrosis share many aspects with tumorigenesis.

A case of synovial chondromatosis of the temporomandibular joint secondary to preauricular trauma.

Synovial chondromatosis is a rare benign arthropathy characterized by chondrometaplasia of the synovial membrane, particularly in the temporomandibular joint (TMJ). The purpose of this article is to describe an uncommon case of synovial chondromatosis arising from the inferior joint space of the TMJ with an enlarged condyle secondary to preauricular trauma in a 44-year-old healthy male. The possible role of a traumatic event in the etiology, the usefulness of the combined performance of CT and MRI examinations for preoperative diagnosis and current treatment are discussed.