The variable manifestations of extraarticular synovial chondromatosis.

Clinically, patients with extraarticular synovial chondromatosis are seen with a juxtaarticular mass due to metaplasia of synovial cells and subsequent formation of cartilaginous nodules. Three patients are described to illustrate the varied clinical and radiographic features of this disease. One patient had involvement of the knee and wrist while another had involvement of the knee along with presumed intraarticular synovial chondromatosis of the elbow. The third patient had a solitary finger lesion. Routine radiographs in extraarticular synovial chondromatosis demonstrate either solitary or multiple calcified juxtaarticular masses with chondroid matrix. Bone scintigraphy reveals intense radionuclide uptake within the calcified masses. Computed tomography clearly defines the extent of the lesion. Arthrography can evaluate for intraarticular extension.