RICE BODIES CONTAINING CALCIUM MICROCRYST ALS IN OSTEOARTHRITIC SYNOVIAL-FLUIDS - A REPORT OF 4 CASES STUDIED BY TRANSMISSION ELECTRON-MICROSCOPY

Rice bodies are often found in inflammatory joint fluid specimens, esp ecially from rheumatoid arthritis patients, but have rarely been repor ted in osteoarthritis. We found rice bodies in knee joint fluid specim ens from four of 88 patients with osteoarthritis. There were three mal es and one female. Age ranged from 61 to 86 years. Three patients had slowly progressive knee osteoarthritis and one had rapidly destructive disease. Abundant, recurrent effusions occurred in all four patients despite one to five local corticosteroid injections per patient and ra diation synovectomy in two patients. The joint fluid specimens contain ed 120 to 320 cellS/mm3 and large numbers of rice bodies that stained with alizarin red S. Transmission electron microscopy studies showed t hat the rice bodies were composed of fibrin and contained numerous int ra- and extra-cellular calcium crystals composed of apatite alone in t wo cases and of a combination of apatite and calcium pyrophosphate dih ydrate in the two others. Collagen fibers and fragments of bone and ca rtilage were present in a few rice bodies. Phagocytic cells, type C sy noviocytes, chrondrocytes and a few inflammatory cells were also seen. These rice bodies composed mainly of fibrin and apatite may have play ed a role in the pathogenesis of the recurrent joint effusions in our patients.