Rice bodies (musculoskeletal)
Rice bodies are multiple small loose intra-articular bodies that macroscopically resemble polished grains of white rice. They are located in the synovial fluid, bursae or tendon sheaths .
Rice bodies can range from asymptomatic to causing joint pain, effusion and occasionally mechanical symptoms such as locking.
The pathogenesis of these loose bodies has been debated and is probably multifactorial. Proposed theories suggest that it may be due to shedding of infarcted synovium, a nidus of cellular debris or they may develop independently subsequently becoming encased by fibrin with different levels of organization.
They are most commonly seen in rheumatoid arthritis but may also be seen in :
- chronic synovitis
- chronic bursitis
- T1: iso-hypointense
- T2: hypointense
- T1 + Gad: non-enhancing
If tightly packed, they may be hard to differentiate especially if isodense to joint effusion.
- synovial chondromatosis
- high T2 signal (when non-mineralized)