Rice Bodies

RICE BODIES (corpora or corpuscula oryzoidea) belong to the group of free joint bodies (see Joint mouse). They are elastic, pale-yellow formations resembling melon seeds, with a layered structure on cross-section. Out of the entire mass of free joint bodies, they can be separated into a distinct group due to the peculiarity of their development, as well as because they are encountered not only in joints, but under analogous conditions also in tendon sheaths, synovial bursae, and hygromas. Rice bodies arise only under conditions of an inflammatory process accompanied to a greater or lesser degree by destruction of the inflamed surface, proliferation of granulation tissue, and almost always the presence of an exudate, frequently with a large amount of fibrin. Until recently, the question of the material substrate from which rice bodies arise has not been definitively resolved. Are these merely masses of fibrin compressed by joint movements, or do rice bodies arise from proliferations of granulation tissue undergoing necrobiosis and fibrinoid transformation? The latter is very probable, since histological examination of rice bodies reveals remnants of cellular elements within them. Their connection with the granulating surface is undoubted, since sometimes unconstricted rice bodies can be seen, and the exudative fluid may be almost absent or serous. The fibrinoid appearance of the mass of rice bodies is also not an argument in favor of their origin from an exudate containing fibrin, since examples of fibrinoid transformation of tissue undergoing necrobiosis are known in pathology. Whatever substrate rice bodies are formed from, their external appearance depends on purely local functional factors of the given regions, such as friction, pressure during movement, and the like. The etiology of the inflammatory process in which rice bodies are encountered is tuberculosis in the vast majority of cases, and tubercle bacilli have been found in rice bodies (Garré). Besides tuberculosis, cases of deforming arthritis, arthritis in syringomyelia (Goldmann) have been described. There is an opinion that tuberculous arthritides, tenosynovitis, bursitis, and hygromas accompanied by the formation of rice bodies have a benign clinical course, and the number of rice bodies in them can be enormous; thus, Sultan described 10,000 rice bodies in a tendon sheath.—For treatment and clinical features, see Joint mouse.