Thank you so much to Dr. Rosanne Metz of Toronto for this case. This 46-year-old man presented with chronic mild dull aching, crepitus and reduced range of motion of his left elbow. Radiographs revealed an intra-articular collection of amorphous, somewhat fl occulent calcifi c densities in a region of soft tissue swelling immediately medial and posterior to the proximal ulna (Figures A and B). DIAGNOSIS: Synoviochondrometaplasia DISCUSSION: a benign arthropathy characterized by formation of intra-articular loose bodies synonyms include osteochondromatosis, osteochondral loose bodies, joint mice synovial metaplasia forms cartilage which detaches and may calcify or ossify, resulting in multiple intra-articular loose bodies clinically most prevalent in males (3:1) between 30-50 years of age 70 percent of cases occur in the knee; elbow is second most frequent site can manifest as insidious but intensifying pain (over years), crepitus and joint locking two main forms: primary – apparently arises spontaneously, but recurrent microtrauma has been implicated; secondary – more common, and develops as a sequela to degenerative or neuropathic joint disease, osteochondritis dessicans, osteochondral fractures, or joint dislocations differential diagnosis includes multiple sesamoid bones, pseudogout, synovioma, pigmented villonodular synovitis and chondrosarcoma surgical removal is usually indicated, but recurrence is not uncommon References: Yochum TR, Rowe LJ. Essentials of Skeletal Radiology. 1997, Williams & Wilkins, Baltimore.