Synovial chondromatosis: a pictorial review

Transcription

1 Synovial chondromatosis: a pictorial review Poster No.: C-1307 Congress: ECR 2014 Type: Educational Exhibit Authors: L. Silva, M. O. E. Castro, B. M. Q. Santos, C. Bilreiro, F. Aleixo; Portimão/PT Keywords: Connective tissue disorders, Diagnostic procedure, Conventional radiography, MR, CT, Musculoskeletal system, Musculoskeletal soft tissue, Musculoskeletal joint DOI: /ecr2014/C-1307 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 25

2 Learning objectives To discuss and illustrate the imaging characteristics of synovial chondromatosis, as observed in different imaging modalities. Page 2 of 25

3 Background Synovial chondromatosis (SC), previously known as synovial osteochondromatosis, synovial chondrometaplasia, articular ecchondrosis and synovial chondrosis, is a benign process characterized by the presence of multiple round cartilaginous nodules or osseous loose bodies within the synovium. It can be classified as primary (benign neoplastic process) or secondary (associated with joint abnormalities, such as mechanical or arthritic conditions that cause intraarticular chondral bodies). Rarely, it may involve extraarticular sites, arising in synovium about the tendons or bursa [1, 2]. Its histologic appearance may suggest a more aggressive chondroid neoplasm. Radiologic findings are frequently pathognomonic, although variable depending on the stage of the disease. Page 3 of 25

4 Findings and procedure details SC classification Primary synovial chondromatosis (PSC) The primary form of SC has an incidence of 1:100,000 and typically affects patients in the third to fifth decades of life, with a male predominance [1, 2] (Fig. 1 on page 10, Fig. 2 on page 11, Fig. 3 on page 11, Fig. 4 on page 12). There is still debate about its physiopathology. Although PSC was first considered to represent chondroid metaplasia in the synovium of a joint, currently, due to recent cytogenetic work, it is considered a benign neoplastic process, with production of similarsized round cartilaginous nodules. These nodules, nourished by synovial fluid, grow and most of them calcify, with some of them progressing to ossification [1, 2]. Secondary synovial chondromatosis (SSC) The secondary form of SC is very common and is associated with joint abnormalities, such as mechanical or arthritic conditions that cause intraarticular chondral bodies [1] (Fig. 5 on page 13, Fig. 6 on page 14, Fig. 7 on page 15). These conditions may promote the detachment of cartilaginous or osteocartilaginous fragments from the articular surface, that become imbedded in the synovium [3, 4]. Like in PSC, these fragments, nourished by synovial fluid, may grow and proliferate [5]. The loose bodies may also stimulate metaplastic changes in the synovial layer, contributing to further development of (osteo)chondral bodies [4, 5]. Because it is frequently related to degenerative arthropathy, patients with SSC are generally older than those with the primary form. Clinical Presentation The clinical diagnosis of SC may be difficult as the clinical history and physical examination are non-specific. The patients most often complain of pain, swelling and restricted range of motion of the affected joint. Symptoms are often insidious at disease onset and are gradually progressive, with an average of 5 years duration before diagnosis [1, 2]. Page 4 of 25

5 The most commonly affected joint is the knee (50%-65%) (Fig. 1 on page 10), followed by the hip (Fig. 2 on page 11), elbow (Fig. 3 on page 11), shoulder (Fig. 4 on page 12) and ankle. Other less commonly affected joints are the metacarpophalangeal, interphalangeal, distal radioulnar, acromioclavicular, temporomandibular, proximal tibiofibular and apophyseal articulations [1, 2]. PSC is usually a monoarticular disease, although up to 5%-10% of cases demonstrate polyarticular involvement (more frequently associated with the secondary form of the disease) [1, 2]. SC, in some cases, may involve extraarticular sites, arising in the synovium about the tendons or bursa (tenosynovial and bursal chondromatosis, respectively) [1, 2, 6] (Fig. 5 on page 13). Clinically, patients with the extraarticular form complain of a painless mass or only mild tenderness upon palpation of the lesion and, unlike the intraarticular form, usually there is no limitation of joint motion [1]. Pathology Macroscopically, PSC consists of hyperplastic synovium covering bluish white, multilobulated, nodular projections of hyaline cartilage diffusely involving the entire joint surface. These subsynovial cartilaginous nodules, or chondromas, may extend into adjacent soft tissues and bursa and may extrinsically erode bone. They are generally uniform in size and shape and their number varies widely from only several to over 1000; sometimes they may coalesce [1], originating a large solitary mass (up to 20 centimeters) (Fig. 8 on page 16). Microscopically, SC is composed of lobules of hyaline cartilage, surrounded by synovial lining. With long-standing disease, these lobules may undergo calcification or ossification which may progress to contain central yellow marrow [1]. A variable degree of synovial proliferation or hyperplasia may also be present. In 1977, Milgram described three stages in PSC: Stage 1 - the chondromas are attached to the synovium; Stage 2 - the chondromas breach the synovium and are released as free bodies into the joint capsule; Stage 3 - the synovial disease becomes inactive but the intraarticular nodules remain. Page 5 of 25

6 It should be pointed out that there is no correlation between these stages versus duration of clinical symptoms or patient age. There is also no evidence in the literature that PSC progresses through these stages in any definite order [1, 2]. The chondromas are often hypercellular with atypical histologic features, including multinucleation, nuclear crowding, nuclear enlargement, hyperchromasia and mild mixoyd changes. These atypical features, which may suggest a malignant cartilage neoplasm, are actually typical for SC. So, correlation of histologic analysis with radiologic features is essential for the correct diagnosis of this benign entity [1, 2]. Imaging features Imaging features of SC are frequently pathognomonic [1, 2]. Radiography Radiographic features of PSC include multiple intraarticular chondral bodies of uniform size, evenly distributed throughout the joint, with "ring-and-arc" chondroid mineralization. With long-stage disease, the pattern of mineralization may progress to enchondral ossification with a peripheral rim cortex of calcification and inner trabecular bone (target appearance) (Fig. 1 on page 10, Fig. 3 on page 11, Fig. 4 on page 12). Bone density is usually preserved, although juxtaarticular osteopenia may develop due to disuse. Secondary osteoarthritis may eventually arise in more advanced untreated disease. In SSC the osteochondral bodies are fewer in number and more variable in size (suggesting various times of origin), often exhibiting several rings of calcification, in contradistinction to the single ring seen in primary disease. Radiographic features associated with the underlying joint abnormality (most commonly, osteoarthritis) are also evident (Fig. 6 on page 14, Fig. 7 on page 15). Extrinsic erosion of bone may be seen in up to 30% of cases, particularly in joints with a tight capsule (hip, wrist, hand and foot) ( Fig. 8 on page 16). Ultrasonography On ultrasound, it may present as a heterogeneous avascular mass, surrounded by fluid, with hyperechoic foci, representing the cartilaginous nodules or osseous loose bodies (Fig. 5 on page 13). Posterior acoustic shadowing may or may not be present, Page 6 of 25

7 depending on the degree of mineralization. Dynamic ultrasound examination may be useful since the nodules may change in position. CT CT is the optimal radiologic modality to identify and characterize the calcified intraarticular fragments. SC presents as a soft tissue mass with low-attenuation and a lobular outline. As on plain films, calcified nodules may present a "ring-and-arc" pattern of mineralization or a target appearance; these changes are better appreciated on CT (Fig. 1 on page 10, Fig. 3 on page 11, Fig. 5 on page 13, Fig. 7 on page 15). CT is also the best imaging modality to evaluate extrinsic bone erosions (Fig. 2 on page 11, Fig. 8 on page 16). After intravenous administration of contrast material, peripheral and septal enhancement may be seen. One shortfall of CT compared to MR is its inability to show marrow invasion. MR MR is the best modality to evaluate the lesion extension as it can depict the degree of extrinsic bone erosion and marrow invasion. Joint effusion is typical and the lesion itself presents as nodules of signal intensity similar to muscle on T1-weighted images and high signal intensity on T2-weighted images, with or without focal areas of low signal intensity or fat-like signal intensity, depending on the degree of mineralization/ossification of the loose bodies. Based on the MR signal intensity of the nodules, Kramer and co-workers described three patterns of PSC: Subtype A (16% of cases) - The chondral nodules are not mineralized. They are difficult to distinguish from the synovial fluid since they share the same signal intensity characteristics (correlates to Milgram stage 1 lesion). Although, after gadolinium administration, there may be peripheral enhancement of the nodules if they are attached to and derive a vascular supply from the synovium (Fig. 1 on page 10); Subtype B (75% of cases) - The nodules are of low signal intensity on all pulse sequences. This is due to calcification of the cartilaginous nodules, which becomes more conspicuous on gradient-echo MR images due to magnetic susceptibility effects (correlates to Milgram stage 2 lesion) (Fig. 1 on page 10, Fig. 3 on page 11, Fig. 4 on page 12); Page 7 of 25

8 Subtype C (9% of cases) - The nodules contain fatty marrow and consequently are isointense to fat on all pulse sequences and show signal suppression on fat saturation sequences. A low signal intensity peripheral rim, similar to bony cortex, may also be seen (correlates to Milgram stage 3 lesion) (Fig. 1 on page 10, Fig. 3 on page 11, Fig. 4 on page 12). MR is also the best exam to evaluate lesion extension along bursae away from the intraarticular component. This feature, if not recognized and treated properly, may lead to local recurrence. As in CT, MR may reveal peripheral and septal enhancement following intravenous administration of contrast material (Fig. 1 on page 10). Differential diagnosis Pigmented villonodular synovitis (PVNS) - this disease is a monoarticular process that may resemble SC subtype A. Due to paramagnetic susceptibility effects of haemosiderin-laden synovial tissue, PVNS typically shows low signal foci on T2-weighted images and susceptibility artifact on gradient-echo sequences. These characteristics are not found on SC subtype A [2]. Radiography demonstrates no calcifications in the lesion. (Fig. 9 on page 17). Synovial chondrosarcoma - most synovial chondrosarcomas arise in pre-existing SC, although progression of SC to malignancy is rare (5% prevalence in the largest published series) [7]. Histologic differentiation of these two diseases is difficult due to overlapping cytoarchitectural features. Some features may be helpful in the differential diagnosis, sugesting malignancy. These include a rapidly growing mass or a recurring mass following excision, metastatic disease, cortical destruction and periosteal reaction with permeation and infiltration into the bone marrow. SC bone erosions, however, may also be deep [2, 8]. Fibrinous "rice bodies" - this entity may be found in TB arthropathy and in inflammatory arthritis (e.g., rheumatoid arthritis). It may mimic the noncalcified subtype of SC on imaging (Fig. 10 on page 18). Osteochondritis dissecans - this is a pathologic process of uncertain etiology affecting the articular cartilage and subchondral bone. Trauma, ischemia, abnormal ossification and genetic factors are suggested causes. It is characterized by partial or complete demarcation of a segment of articular cartilage and subchondral bone with or without ultimate detachment and extrusion into the joint. In this way, it may resemble SC subtype B or C, Page 8 of 25

9 although in osteochondritis dissecans the articular surface defects should be clearly depicted [9] (Fig. 11 on page 19). Lipoma arborescens - this disease is a rare idiopathic intra-articular lesion characterized by nonneoplastic fatty deposits that replace and distend the synovium. These fatty deposits follow fat signal intensity on all MR pulse sequences, which can resemble SC subtype C. However, on plain radiographs or CT scan there will be no ossified loose nodules, but joint effusion with radiolucent areas suggestive of fat (Fig. 12 on page 20). Coexistent degenerative changes are frequently present. The exact cause is unknown, but the most accepted hypothesis suggests that lipoma arborescens represents a nonspecific synovial reaction to inflammatory or traumatic stimuli [8, 10]. Treatment and prognosis Synovial chondromatosis is treated by either open or arthroscopic surgical resection, although the latter technique cannot be used to treat extraarticular disease. Removal of chondral bodies, synovectomy or a combination of both may be necessary. Recurrent disease may be secondary to incomplete resection, with recurrence rates ranging from 3% to 23% [1, 2]. Page 9 of 25

10 Images for this section: Fig. 1: Primary synovial chondromatosis of the right knee, in a 26-year-old female patient. (a) Lateral radiograph of the right knee shows several small intra-articular nodules, uniform in size, with "ring-and-arc" chondroid mineralization. These are better depicted on CT (b, c, h). MR (d, e, f, g, i) demonstrates that most of these nodules are slightly hyperintense to muscle on T1-weighted (d) and PD-weighted fat saturated (e) images (subtype A), while others are calcified, hypointense in all pulse sequences (subtype B). Notice that one of the nodules, located at the popliteal recess, exhibits adipose bone marrow foci (subtype C), as demonstrated in T1-weighted (g) and CT images (h). After gadolinium administration, peripheral and septal enhancement is evident (i). Page 10 of 25

11 Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Fig. 2: Primary synovial chondromatosis of the right hip, in a 19-year-old male. Large erosion on the postero-medial aspect of the right femoral head (arrow), produced by a non mineralized chondral body (subtype A). Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 11 of 25

12 Fig. 3: Primary synovial chondromatosis of the right elbow, in a 50-year-old woman. (a) Plain radiographs of the right elbow show multiple small calcified nodules, uniform in size. CT scan (b, c) shows calcified and ossified chondral bodies. Notice the geodes (arrow in b) and osteophytes (arrow in c) due to secondary osteoarthritis. (d, e, f, g) MR confirms the presence of subtypes B (hipointense on all pulse sequences) and C (bone marrow foci) chondral nodules. Notice the magnetic susceptibility effects on the gradient-echo image (g). Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 12 of 25

13 Fig. 4: Primary synovial chondromatosis of the left shoulder, in a 27-year-old man. (a, b) Plain radiographs show multiple small nodules, uniform in size, with chondroid-like calcifications. (c, d, e, f, g, h) MR reveals distension of the axillary and subscapularis recesses, as well as of the biceps tendon sheath, produced by these calcified and ossified (subtypes B and C) loose bodies, with extension into adjacent soft tissues (arrow and arrowhead in h). Notice the magnetic susceptibility effects on the gradient-echo image (f). Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 13 of 25

14 Fig. 5: Synovial chondromatosis of the left anserine bursa secondary to a tibial exostosis, in a 13-year-old female patient. (a) Anteroposterior radiograph of the left knee shows soft tissue densities with chondroid-like calcifications adjacent to the medial part of the proximal tibia. A medial tibial exostosis is faintly seen (arrow). (b) Ultrasound of the anserine bursa shows a heterogeneous avascular mass with hyperecoic foci, some of which display acoustic shadowing. (c) CT scan shows a small medial tibial exostosis-like bony outgrowth in the area of the pes anserinus, shaped like a rose thorn, consistent with a pes anserinus spur (arrow). Surrounding this lesion, within the anserine bursa, several loose bodies with a "ring-and-arc" chondroid pattern of mineralization are present. (d, e, f) MR depicts four loose bodies inside a fluid distended anserine bursa, isointense to muscle on T1 (d) and hyperintense on T2 (e), with hypointense mineralized portions. After gadolinium administration, peripheral enhancement is evident (f). Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 14 of 25

15 Fig. 6: Synovial chondromatosis of the left knee secondary to osteoarthritis in a 67year-old man. Anteroposterior (a) and lateral (b) plain radiographs of the left knee show osteoarthitic changes and calcified nodular bodies posterior to the knee joint (arrow in b). (c) Coronal T1-weighted MR images further demonstrates the osteoarthritic changes (bone spurs and articular cartilage loss). Sagital PD-weighted (d) and axial fat saturated PD-weighted (e) images show low signal intensity loose bodies inside a Baker's cyst. Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 15 of 25

16 Fig. 7: Synovial chondromatosis of the knee secondary to osteoarthritis in a 50-yearold woman. CT scan shows osteophytes and narrowing of joint spaces, consistent with osteoarthritis. Notice the variable sized ossified intra-articular loose bodies (arrows in c and d). Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 16 of 25

17 Fig. 8: Large solitary synovial chondromatosis of the right shoulder in a 73-year-old woman. (a) Anteroposterior radiograph shows a large solitary calcification adjacent to the medial aspect of the humerus, causing extrinsic pressure erosion on the bone, with well defined sclerotic margins. Axial (b) and coronal (c) CT scan better depict the pattern of mineralization, with a peripheral rim cortex of calcification and inner nonmineralized component. Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 17 of 25

18 Fig. 9: Pigmented villonodular synovitis of the left knee in a 65-year-old man. Sagital PD (a) and T2-weighted with fat saturation (b), coronal T2*(c) and PD-weighted (d) and axial PD-weighted with fat saturation (e) images show multiloculated joint effusion with low signal foci and areas of synovial proliferation, more prominent in the suprapattelar recess. (f) Plain radiographs show no abnormal calcifications in the lesion. These findings may mimic SC subtype A. Notice the extensive magnetic susceptibility artifacts on the T2* image. Department of Radiology, Centro Hospitalar e Universitário de Coimbra - Coimbra/PT Page 18 of 25

19 Fig. 10: Flexor tenosynovitis of the left wrist with rice bodies in a 46-year-old male patient, complaining of swelling and pain after a pig bite in the hand. MR shows distention of the tendinous sheath of the flexor pollicis longus and common flexor sheath by innumerable same sized nodules, isointense to muscle on T1-weighted (a) and slightly hyperintense on T2-weighted (b) and fat saturated PD-weighted images (c, d). After gadolinium injection (e), synovial enhancement is evident, but no enhancement of the loose bodies can be appreciated. (f) Ultrasound reveals a hypoechoic hourglass-like distension of the flexor tendon sheath with a subtle nodular echostructure. (g, h) On plain radiographs, no calcified nodules are seen. These nodular structures can be difficult to distinguish from noncalcified SC on imaging. Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 19 of 25

20 Fig. 11: Osteochondritis dissecans of the lateral femoral condyle of the right knee in a 38-year-old female. CT scan on coronal plane shows an irregular defect in the articular surface of the medial aspect of the lateral femoral condyle (arrow in a). In a more posterior location, a calcified loose body is seen (arrowhead in b). This is consistent with osteochondritis dissecans. Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 20 of 25

21 Fig. 12: Lipoma arborescens of the left knee in a 59-year-old male. (a, b, c, d) Axial and coronal T1-weighted and T2-weighted with fat saturation MR sequences depict heterogeneous joint effusion, containing nodular and lobular images that follow the signal intensity of fat on all pulse sequences. This may resemble SC subtype C, but there are no calcified or ossified nodules on the plain radiographs (e, f), which show extensive degenerative changes and fullness of the suprapatellar recess with faint radiolucent areas within it, suggestive of fat. Radiologia, Centro Hospitalar do Barlavento Algarvio - Portimão/PT Page 21 of 25

22 Conclusion The pathologic appearance of SC may be misleading because of significant histologic atypia, and therefore radiologic correlation is vital to achieve a correct diagnosis. CT is the best imaging modality to detect calcified bodies. Both CT and MR are good in evaluating bone erosions, although MR is the optimal modality to detect bone marrow invasion. Due to its superior musculoskeletal anatomical definition, MR can also show soft tissue and extraarticular involvement. A multimodality imaging approach is desired to fully characterize this condition and to allow for optimal patient management. Page 22 of 25

23 Personal information Luís Duarte Silva, MD Miguel Oliveira e Castro, MD Bruno Santos, MD Carlos Bilreiro, MD Francisco Aleixo, MD Department of Radiology, Centro Hospitalar do Algarve, Portimão, Portugal Page 23 of 25

24 References 1. Murphey MD, Vidal JA, Fanburg-Smith JC, Gajewski DA. From the Archives of the AFIP: Imaging of Synovial Chondromatosis with Radiologic-Pathologic Correlation. RadioGraphics 2007, 27: McKenzie G, Raby N, Ritchie D. A pictorial review of primary synovial osteochondromatosis. EurRadiol 2008, 18: Wuisman PIJM, Noorda RJP, Jutte PC. Chondrosarcoma secondary to synovial chondromatosis. Report of two cases and review of the literature. Arch Orthop Trauma Surg 1997, 116: Schofield TD, Pitcher JD, Youngberg R. Synovial chondromatosis simulating neoplastic degeneration of osteochondroma: findings on MRI and CT. Skeletal Radiol 1994, 23: Peh WC, Shek TW, Davies AM, Wong JW, Chien EP. Osteochondroma and secondary synovial osteochondromatosis. Skeletal Radiol : Luís Duarte Silva, Miguel Oliveira e Castro, Bruno Santos, Carlos Bilreiro, Francisco Aleixo (2013, Dec 19). Synovial osteochondromatosis of the anserine bursa secondary to a tibial exostosis, {Online}. URL: 7. Davis RI, Hamilton A, Biggart JD. Primary synovial chondromatosis: a clinicopathologic review and assessment of malignant potential. Hum Pathol 1998;29: Sheldon PJ, Forrester DM, Learch TJ. Imaging of Intraarticular Masses. RadioGraphics 2005, 25: Boutin RD, Januario, JA, Newberg AH, Gundry CR, Newman JS. MR Imaging Features of Osteochondritis Dissecans of the Femoral Sulcus. American Journal of Roentgenology 2003, 180: Coll JP, Ragsdale BD, Chow B, Daughters TC. Best Cases from the AFIP: Lipoma Arborescens of the Knees in a Patient with Rheumatoid Arthritis. RadioGraphics 2011, 31: Page 24 of 25

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