Clinical images: Synovitis on magnetic resonance imaging; osteochondromatosis at hip arthroscopy



Illustration 1.

The patient, an active 40-year-old man, presented with a long history of left groin pain and reduced range of motion of the left hip. Magnetic resonance imaging showed synovitis of the left hip with a small associated effusion, reported as being suggestive of pigmented villonodular synovitis (A). At arthroscopy, a number of very large, loose, cartilaginous bony fragments were observed; histologic analysis confirmed a diagnosis of benign osteochondromatosis (B). The fragments were successfully removed arthroscopically, after which the patient's symptoms resolved. In the setting of pain and reduced range of motion of the hip, osteochondromatosis should be considered, even if imaging results do not support this diagnosis.