Mycobacterium intracellulare Tenosynovitis with Rice Body Formation with Literature Review

Rice body formation is a rare response to chronic inflammation of the synovial membrane. It is most commonly associated with rheumatoid arthritis and tuberculosis. Recently, there have been reports of rice bodies caused by non-tuberculous mycobacterial infection. We describe a case of rice body formation in a 69-year-old man who presented with pain and swelling in his third finger for six months after being punctured by a wire 1 year ago. He had no other notable recent medical history. Magnetic resonance imaging showed a large amount of fluid collection with diffuse thickening and enhancement of the synovium and rice bodies along the flexor tendon of the third finger. During surgery, multiple granular white rice bodies were found from the third carpal bone to the distal phalanx. Mycobacterium intracellulare was identified through mycobacterial culture and the patient was treated with rifampin, ethambutol, and clarithromycin, without recurrence. This case reveals that Mycobacterium intracellulare infection can cause tenosynovitis with rice bodies.