Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

: 2003  |  Volume : 13  |  Issue : 3  |  Page : 281--283

Synovial osteochondromatosis

NA Pendse, A Diwan, V Menghani 
 Vardhman MRI Centre, SDM Hospital Campus, Bhawani Singh Marg, Jaipur-302015, India

Correspondence Address:
N A Pendse
Vardhman MRI Centre, SDM Hospital Campus, Bhawani Singh Marg, Jaipur-302015

How to cite this article:
Pendse N A, Diwan A, Menghani V. Synovial osteochondromatosis.Indian J Radiol Imaging 2003;13:281-283

How to cite this URL:
Pendse N A, Diwan A, Menghani V. Synovial osteochondromatosis. Indian J Radiol Imaging [serial online] 2003 [cited 2021 Jan 28 ];13:281-283
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Synovial Osteochondromatosis ( SOC ), also known as Osteochondromatosis or Synovial Chondromatosis, is an unusual benign neoplasm affecting typically the large joints in young to middle aged adults, with a predilection of two to four fold for men over women. The disease is usually monoarticular and joints affected are Knee, Hip, Shoulder, Elbow and Ankle, though any synovial joint may be affected. The disease is characterized by synovial proliferation, calcification and formation of multiple (even hundreds) intra articular loose bodies.


A 17 year old male presented with complaints of intermittent right hip pain and restriction of movements since five years. There was no history of trauma or any other significant illness. On examination the joint was tender and showed fixed flexion deformity. Routine lab investigations were normal.

X ray of the Hip showed multiple juxta articular calcified / ossified bodies [Figure 1]. Mild reduction in joint space and osteopenia were also noted. No saucerization or scalloping was seen.

CT scan of Hip confirmed the presence of osseous bodies within the joint [Figure 2].

MRI of the Hip was performed which showed multiple loose bodies and associated synovial changes. The loose bodies showed an isointense periphery and hypointense centre on T1 images [Figure 3],[Figure 4], while on T2 [Figure 5],[Figure 6] and Fat Suppressed IR images they showed a hypointense periphery and central hyperintensity. The affected synovium and associated joint effusion appeared hyperintense on both T2 and FSIR images [Figure 4],[Figure 5].


SOC is a benign neoplasm characterized by synovial proliferation & chondrometaplasia, and may affect the synovial lining of a joint, bursa or tendon sheath [1]. The disease is usually monoarticular [2]. The affected synovium undergoes metaplastic transformation into cartilage forming chondroblasts, which mature into chondrocytes to form nodules of hyaline cartilage [3].

Nodular proliferation of the synovium occurs and fragments are pushed towards the joint cavity ( path of least resistance ), where they survive and enlarge to form cartilaginous bodies. The central portions necrose and undergo calcification followed by enchondral ossification. They may break away giving rise to the classical picture of multiple intrarticular osseous loose bodies or may remain attached to articular surface of the synovium. The affected joint cavity becomes distended and packed with loose bodies resulting in pain, mechanical obstruction, joint destruction and finally degeneration. Three phases of the disease are described : synovial proliferation and metaplasia without loose bodies, metaplasia with loose bodies, and an inactive phase with loose bodies but without synovial metaplsia [3].

If the osseous bodies are in a non stress bearing environment they may be resorbed by osteoclasts and disappear, though this is rather exceptional.

Malignant transformation into Chondrosarcoma is reported but is extremely rare [1].

Usual clinical presentation is that of intermittent joint pains, swelling, stiffness and restriction of movements and instability. Occasionally, locking or internal derangement due to impingement by loose body may be the presenting symptom, this being more common in the knee where it may mimic a meniscal tear [3].

Radiographic evaluation is frequently diagnostic and loose bodies may be picked up in upto seventy percent of cases. In instances where little or no ossification has occurred, only a soft tissue mass or a mass with fine granular calcification is seen. As the degree of ossification increases, more and more radiodense bodies may be picked up and in advanced cases striking nodular calcification makes the diagnosis immediately evident [4]. Chronic cases will show changes of secondary degenerative arthritis. Arthrography may be used in cases lacking ossification where loose bodies are seen as radiolucent defects [1].

CT scan shows the presence of mineralized or unmineralized loose bodies and findings are similar to those on radiographic evaluation.

MRI is the preferred investigative modality because of it's ability to demonstrate in exquisite detail the synovial changes as well as the presence of loose bodies. The affected synovium and effusion appear hyperintense on T2 and FSIR images and iso to hypointense on T1 images. Contrast enhancement enables further differentiation between the two. The loose bodies may show variable signal depending on the degree of mineralization [3],[4],[5]. Surgical treatment by complete synovectomy is preferred though recurrence is not uncommon [6].


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