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Synovial Osteochondromatosis

  • Author: Johnny U V Monu, MD, MS; Chief Editor: Felix S Chew, MD, MBA, MEd  more...
 
Updated: Apr 23, 2015
 

Overview

Synovial osteochondromatosis (SOC) is a benign condition characterized by synovial membrane proliferation (demonstrated in the images below) and metaplasia. The entity also is termed synovial chondromatosis. The synovial lining of a joint, bursa, or tendon sheath undergoes nodular proliferation, and fragments may break off from the synovial surface into the joint.[1] There, nourished by synovial fluid, the fragments may grow, calcify, or ossify. The intra-articular fragment may vary in size from a few millimeters to a few centimeters.[2, 3, 4, 5, 6, 7]

Malignant transformation of synovial chondromatosis to synovial chondrosarcoma (CHS) is recognized to be a rare event. In a study of 78 patients who presented with primary synovial chondromatosis, 5 went on to develop malignant change (incidence of 6.4%). The mean age at first diagnosis of synovial chondromatosis was 28 years, and the median time from original diagnosis to malignant transformation was 20 years (range, 2.7-39 years).[8]

The images below present a detailed view of SOC of the shoulder.

Plain radiograph of a 19-year-old man who initiall Plain radiograph of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Frontal radiograph of the shoulder shows multiple rounded, calcified bodies in the axillary recess and in the subscapularis bursa.
Magnetic resonance imaging (MRI) scan of a 19-year Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Coronal T1-weighted image of the shoulder shows multiple hypointense foci in the axillary recess and in the subacromial space. Note the hypointense foci deep to the deltoid in the subdeltoid bursa. The foci result from the presence of osteocartilaginous bodies in these areas. Cartilage bodies may be present in the sleeve of the biceps tendon.
Magnetic resonance imaging (MRI) scan of a 19-year Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Oblique sagittal proton density– and T2-weighted images show multiple, rounded, hypointense foci in the subscapularis bursa projecting underneath the coracoid process. Note the high signal intensity simulating the presence of surrounding fluid from the joint effusion. Some of the high signal intensity results from edematous proliferating synovium. The synovium is dissecting the body of the scapula and the infraspinatus. Note the solitary osteochondral body in that location.
Magnetic resonance imaging (MRI) scan of a 19-year Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Oblique sagittal proton density– and T2-weighted images show multiple, rounded, hypointense foci in the subscapularis bursa projecting underneath the coracoid process. Note the high signal intensity simulating the presence of surrounding fluid from the joint effusion. Some of the high signal intensity results from edematous proliferating synovium. The synovium is dissecting the body of the scapula and the infraspinatus. Note the solitary osteochondral body in that location.
Image from a 19-year-old man who initially present Image from a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Some of the multiple stones were removed from the patient's shoulder during surgery. Note the lamellate pattern to the chondral bodies.
Sagittal T1-weighted and sagittal short-tau invers Sagittal T1-weighted and sagittal short-tau inversion recovery (STIR) images of the ankle show proliferating synovium, which is seen as foci of increased signal intensity on the STIR images.
Sagittal T1-weighted and sagittal short-tau invers Sagittal T1-weighted and sagittal short-tau inversion recovery (STIR) images of the ankle show proliferating synovium, which is seen as foci of increased signal intensity on the STIR images.

The degree of calcification varies, and calcification may be seen as a few calcific specks or as foci of frankly ossified bodies.[9] The fragments may be found free within the joint cavity, or they may be embedded within the proliferating synovium, which may extend into the surrounding soft tissues. The natural history of SOC entails gradual progression of disease, joint deterioration, and secondary osteoarthritis. Essentially, the disease is a benign process, and although studies in the literature have reported malignant transformation, this finding is decidedly unusual.

Preferred examination

Radiographic findings are frequently diagnostic. CT scans and CT arthrograms also may be used, especially for demonstrating noncalcified intra-articular bodies. MRI usually helps establish the diagnosis, and the images demonstrate the true extent of the disease. Ultrasonographic examination may be used to investigate accessible joints.

Radiographs should be obtained first.[10, 11, 12, 13, 14] MRI scans should then be obtained preoperatively. When MRI is not readily available, CT arthrography may be performed.

Limitations of techniques

Radiographs may not demonstrate noncalcified bodies. CT scans may not demonstrate the full extent of proliferating synovial disease. SOC may be confused with pigmented villonodular synovitis (PVNS) if only MRI scans are available, and plain radiographs may help in such cases.

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Radiography

Plain radiographs frequently show characteristic features, including multiple (usually >5) calcified or osseous bodies within the joint or bursa, as in the images below. When fragments are not calcified, intrasynovial fragments may not be seen on plain images, and arthrographic studies are required to demonstrate the bodies.

Frontal radiograph of the knee shows multiple calc Frontal radiograph of the knee shows multiple calcified bodies in the proximal tibiofibular joint in a patient with synovial osteochondromatosis.
Lateral radiograph of the knee shows multiple calc Lateral radiograph of the knee shows multiple calcified bodies in the proximal tibiofibular joint in a patient with synovial osteochondromatosis.
Frontal radiograph of a patient with synovial oste Frontal radiograph of a patient with synovial osteochondromatosis of the knee joint. The bodies are located in the popliteal space of the knee.
Lateral radiograph of a patient with synovial oste Lateral radiograph of a patient with synovial osteochondromatosis of the knee joint. The bodies are located in the popliteal space of the knee.

Pressure erosions (saucerization; as demonstrated in the image below) and cyst formation can be seen in adjacent bone, although this is more typical for joints with lax capsules, such as the hip. A similar observation may be found in patients with PVNS.

Lateral view of the ankle of a man who presented w Lateral view of the ankle of a man who presented with ankle discomfort. Increased soft-tissue density is noted both anteriorly and posteriorly, simulating joint effusion. Note the stippled calcification seen posteriorly, resulting from calcification in some of the cartilage bodies. The anterior corner of the distal tibia is truncated as a result of pressure erosion. Similar pressure erosions may be seen in hip and knee joints in which synovial osteochondromatosis occurs. Note the mild osteopenia around the ankle; this is likely a result of hyperemia.

Degree of confidence

With plain radiography, differential diagnoses include degenerative joint disease in which osteophytes have broken off into the joint; however, SOC tends to have a larger number of bodies in the joint (usually >5). Other differential diagnoses include soft-tissue and intra-articular chondromas. In advanced stages of SOC, secondary degenerative changes are often observed.

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Computed Tomography

CT scanning is rarely necessary to make a diagnosis, and the CT scan's features are similar to findings on plain radiographs. CT scanning may show noncalcified bodies.

See the CT scans depicting synovial osteochondromatosis, below.

Axial computed tomography (CT) images of the elbow Axial computed tomography (CT) images of the elbow at the level of the radial ulna joint. Note the presence of osteocartilaginous bodies in the radial ulna joint and also posteriorly.
Sagittal reconstruction from a spiral computed tom Sagittal reconstruction from a spiral computed tomography (CT) scan series of the elbow shows the distribution of the calcified bodies in the olecranon fossa and around the posterior and anterior aspects of the joint.
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Magnetic Resonance Imaging

In synovial osteochondromatosis (SOC), T1-weighted and proton density–weighted images often demonstrate multiple rounded bodies that are isointense or hypointense relative to muscle. Some bodies demonstrate signal intensity (or lack of it) similar to that of cortical bone.[15]

See the magnetic resonance images depicting SOC, below.

Magnetic resonance imaging (MRI) scan of a 19-year Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Coronal T1-weighted image of the shoulder shows multiple hypointense foci in the axillary recess and in the subacromial space. Note the hypointense foci deep to the deltoid in the subdeltoid bursa. The foci result from the presence of osteocartilaginous bodies in these areas. Cartilage bodies may be present in the sleeve of the biceps tendon.
Magnetic resonance imaging (MRI) scan of a 19-year Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Oblique sagittal proton density– and T2-weighted images show multiple, rounded, hypointense foci in the subscapularis bursa projecting underneath the coracoid process. Note the high signal intensity simulating the presence of surrounding fluid from the joint effusion. Some of the high signal intensity results from edematous proliferating synovium. The synovium is dissecting the body of the scapula and the infraspinatus. Note the solitary osteochondral body in that location.
Magnetic resonance imaging (MRI) scan of a 19-year Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Oblique sagittal proton density– and T2-weighted images show multiple, rounded, hypointense foci in the subscapularis bursa projecting underneath the coracoid process. Note the high signal intensity simulating the presence of surrounding fluid from the joint effusion. Some of the high signal intensity results from edematous proliferating synovium. The synovium is dissecting the body of the scapula and the infraspinatus. Note the solitary osteochondral body in that location.
Sagittal T1-weighted and sagittal short-tau invers Sagittal T1-weighted and sagittal short-tau inversion recovery (STIR) images of the ankle show proliferating synovium, which is seen as foci of increased signal intensity on the STIR images.
Sagittal T1-weighted and sagittal short-tau invers Sagittal T1-weighted and sagittal short-tau inversion recovery (STIR) images of the ankle show proliferating synovium, which is seen as foci of increased signal intensity on the STIR images.

Some bodies may lie free, and some are completely intra-articular, whereas others may be adherent to the synovial surface. Some bodies may be found deep in the synovial lining, embedded in adjacent soft tissue.

T2-weighted images may show areas of high signal intensity consistent with joint effusion and synovial thickening.

In a study of 144 patients with synovial chondromatosis of the temporomandibular joint evaluated by MRI, 3 lesion types were visualized: loose body (32.6%), homogeneous mass (49.3%), and a mixture of the two (18.1%). Bony evaluations included 4 stages of erosion: without erosion, chondral breakdown, bony absorption, and bony perforation. Of the bony perforations, 80% were homogeneous masses and 20% were mixed loose body/homogenous mass.[16]

The intravenous administration of a gadolinium-based contrast material usually enables the differentiation of joint effusion from hyperplastic synovium, which shows heterogeneous enhancement. Joint effusion may be hemorrhagic.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or magnetic resonance angiography scans.

NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness.

Degree of confidence

When the presence of calcification is ambiguous, plain radiographs are useful adjuncts to MRI scans for establishing the diagnosis.

False positives/negatives

On MRI scans, SOC may appear somewhat similar to pigmented villonodular synovitis (PVNS), but the 2 conditions are easily differentiated by using plain radiographs.

The distinguishing feature of SOC is calcification, which appears as signal voids in the synovium. This finding is optimally visualized when the intra-articular fragments are calcified.

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Nuclear Imaging

Radionuclide studies (see the image below) may be obtained when the plain radiographic features are not clear. The affected areas usually show increased radionuclide uptake on technetium-99m bone scans.[17]

Delayed bone scan shows diffusely increased uptake Delayed bone scan shows diffusely increased uptake around the tibiotalar joint. This indicates increased metabolic activity and is consistent with synovitis around the ankle.
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Contributor Information and Disclosures
Author

Johnny U V Monu, MD, MS Professor of Imaging Sciences and Orthopedics, University of Rochester School of Medicine and Dentistry; Head and Program Director, Musculoskeletal Radiology, Department of Radiology, University of Rochester Strong Memorial Medical Center

Johnny U V Monu, MD, MS is a member of the following medical societies: Radiological Society of North America

Disclosure: Nothing to disclose.

Specialty Editor Board

Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand

Disclosure: Nothing to disclose.

Javier Beltran, MD Chair, Department of Radiology, Maimonides Medical Center

Disclosure: Nothing to disclose.

Chief Editor

Felix S Chew, MD, MBA, MEd Professor, Department of Radiology, Vice Chairman for Academic Innovation, Section Head of Musculoskeletal Radiology, University of Washington School of Medicine

Felix S Chew, MD, MBA, MEd is a member of the following medical societies: American Roentgen Ray Society, Association of University Radiologists, Radiological Society of North America

Disclosure: Nothing to disclose.

Additional Contributors

David S Levey, MD Orthopedic and Neurospinal MRI, Forensic Diagnostic Radiologist; President, David S Levey, MD, PA, San Antonio, Texas

David S Levey, MD is a member of the following medical societies: International Society of Forensic Radiology and Imaging, Forensic Expert Witness Association, Technical Advisory Service for Attorneys, Bexar County Medical Society, Texas Medical Association

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author Mayumi Oka, MD,to the development and writing of this article.

References
  1. Garner HW, Bestic JM. Benign synovial tumors and proliferative processes. Semin Musculoskelet Radiol. 2013 Apr. 17(2):177-8. [Medline].

  2. Pau M, Bicsák A, Reinbacher KE, Feichtinger M, Kärcher H. Surgical treatment of synovial chondromatosis of the temporomandibular joint with erosion of the skull base: a case report and review of the literature. Int J Oral Maxillofac Surg. 2013 Dec 3. [Medline].

  3. Reed LS, Foster MD, Hudson JW. Synovial chondromatosis of the temporomandibular joint: a case report and literature review. Cranio. 2013 Oct. 31(4):309-13. [Medline].

  4. Zhu Y, Zheng C, Deng Y, Zhang Y, Hu X. Arthroscopic surgery for removal of 112 loose bodies of synovial chondromatosis of the temporomandibular joint. J Craniofac Surg. 2013 Nov. 24(6):2166-9. [Medline].

  5. Dimnjakovic D, Bojanic I, Mahnik A, Smoljanovic T. Synovial chondromatosis of the elbow. Coll Antropol. 2013 Jun. 37(2):633-8. [Medline].

  6. Fukui K, Kaneuji A, Amaya S, Matsumoto T. Synovial osteochondromatosis of the hip with femoroacetabular impingement and osteoarthritis: a case report. J Orthop Surg (Hong Kong). 2013 Apr. 21(1):117-21. [Medline].

  7. Ho YY, Choueka J. Synovial chondromatosis of the upper extremity. J Hand Surg Am. 2013 Apr. 38(4):804-10. [Medline].

  8. Evans S, Boffano M, Chaudhry S, Jeys L, Grimer R. Synovial chondrosarcoma arising in synovial chondromatosis. Sarcoma. 2014. 2014:647939. [Medline]. [Full Text].

  9. Matsumura Y, Nomura J, Nakanishi K, Yanase S, Kato H, Tagawa T. Synovial chondromatosis of the temporomandibular joint with calcium pyrophosphate dihydrate crystal deposition disease (pseudogout). Dentomaxillofac Radiol. 2012 Dec. 41(8):703-7. [Medline]. [Full Text].

  10. Goldberg RP, Genant HK. Calcified bodies in popliteal cysts: a characteristic radiographic appearance. AJR Am J Roentgenol. 1978 Nov. 131(5):857-9. [Medline].

  11. Kenan S, Abdelwahab IF, Klein MJ, et al. Case report 817: synovial chondrosarcoma secondary to synovial chondromatosis. Skeletal Radiol. 1993 Nov. 22(8):623-6. [Medline].

  12. Adams ME, Saifuddin A. Characterisation of intra-articular soft tissue tumours and tumour-like lesions. Eur Radiol. 2007 Apr. 17(4):950-8. [Medline].

  13. Prager RJ, Mall JC. Arthrographic diagnosis of synovial chondromatosis. Am J Roentgenol. 1976 Aug. 127(2):344-6. [Medline].

  14. Noyek AM, Holgate RC, Fireman SM, et al. The radiologic findings in synovial chondromatosis (chondrometaplasia) of the temporomandibular joint. J Otolaryngol Suppl. 1977. 3:45-8. [Medline].

  15. Ontell F, Greenspan A. Chondrosarcoma complicating synovial chondromatosis: findings with magnetic resonance imaging. Can Assoc Radiol J. 1994 Aug. 45(4):318-23. [Medline].

  16. Chen MJ, Yang C, Qiu YT, Jiang Q, Shi HM, Wei WB. Synovial chondromatosis of the tempromandibular joint: Relationship between MRI information and potential aggressive behavior. J Craniomaxillofac Surg. 2015 Apr. 43(3):349-54. [Medline].

  17. Zimmerman C, Sayegh V. Roentgen manifestations of synovial osteochondromatosis. Am J Roentgenol Radium Ther Nucl Med. 1960 Apr. 83:680-6. [Medline].

  18. Reed LS, Foster MD, Hudson JW. Synovial chondromatosis of the temporomandibular joint: a case report and literature review. Cranio. 2013 Oct. 31(4):309-13. [Medline].

 
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Plain radiograph of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Frontal radiograph of the shoulder shows multiple rounded, calcified bodies in the axillary recess and in the subscapularis bursa.
Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Coronal T1-weighted image of the shoulder shows multiple hypointense foci in the axillary recess and in the subacromial space. Note the hypointense foci deep to the deltoid in the subdeltoid bursa. The foci result from the presence of osteocartilaginous bodies in these areas. Cartilage bodies may be present in the sleeve of the biceps tendon.
Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Oblique sagittal proton density– and T2-weighted images show multiple, rounded, hypointense foci in the subscapularis bursa projecting underneath the coracoid process. Note the high signal intensity simulating the presence of surrounding fluid from the joint effusion. Some of the high signal intensity results from edematous proliferating synovium. The synovium is dissecting the body of the scapula and the infraspinatus. Note the solitary osteochondral body in that location.
Magnetic resonance imaging (MRI) scan of a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Oblique sagittal proton density– and T2-weighted images show multiple, rounded, hypointense foci in the subscapularis bursa projecting underneath the coracoid process. Note the high signal intensity simulating the presence of surrounding fluid from the joint effusion. Some of the high signal intensity results from edematous proliferating synovium. The synovium is dissecting the body of the scapula and the infraspinatus. Note the solitary osteochondral body in that location.
Image from a 19-year-old man who initially presented with a history of shoulder pain of insidious onset. The patient was found to have synovial osteochondromatosis. Some of the multiple stones were removed from the patient's shoulder during surgery. Note the lamellate pattern to the chondral bodies.
Frontal radiograph of the knee shows multiple calcified bodies in the proximal tibiofibular joint in a patient with synovial osteochondromatosis.
Lateral radiograph of the knee shows multiple calcified bodies in the proximal tibiofibular joint in a patient with synovial osteochondromatosis.
Frontal radiograph of a patient with synovial osteochondromatosis of the knee joint. The bodies are located in the popliteal space of the knee.
Lateral radiograph of a patient with synovial osteochondromatosis of the knee joint. The bodies are located in the popliteal space of the knee.
Lateral view of the ankle of a man who presented with ankle discomfort. Increased soft-tissue density is noted both anteriorly and posteriorly, simulating joint effusion. Note the stippled calcification seen posteriorly, resulting from calcification in some of the cartilage bodies. The anterior corner of the distal tibia is truncated as a result of pressure erosion. Similar pressure erosions may be seen in hip and knee joints in which synovial osteochondromatosis occurs. Note the mild osteopenia around the ankle; this is likely a result of hyperemia.
Delayed bone scan shows diffusely increased uptake around the tibiotalar joint. This indicates increased metabolic activity and is consistent with synovitis around the ankle.
Sagittal T1-weighted and sagittal short-tau inversion recovery (STIR) images of the ankle show proliferating synovium, which is seen as foci of increased signal intensity on the STIR images.
Sagittal T1-weighted and sagittal short-tau inversion recovery (STIR) images of the ankle show proliferating synovium, which is seen as foci of increased signal intensity on the STIR images.
Lateral radiograph of the elbow of a 29-year-old man who presented with locking and reduced range of motion of the elbow. Soft-tissue fullness simulating effusion is noted. In addition, rounded, calcified bodies are seen anteriorly and posteriorly around the elbow.
Axial computed tomography (CT) images of the elbow at the level of the radial ulna joint. Note the presence of osteocartilaginous bodies in the radial ulna joint and also posteriorly.
Sagittal reconstruction from a spiral computed tomography (CT) scan series of the elbow shows the distribution of the calcified bodies in the olecranon fossa and around the posterior and anterior aspects of the joint.
 
 
 
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