Rice body formation without rheumatic disease or tuberculosis infection in a sausage ring finger – a case report

Abstract

Subcutaneous masses in the finger gather numerous lesions, among which tumors, inflammation-induced lesions, and post-traumatic lesions. Rice bodies are very unfrequent lesions, encountered in rheumatoid or tuberculous chronic synovitis. We present the case of a young patient with no history of tuberculosis infection or rheumatoid pathology who required surgical treatment for a rice body formation localized on the palmar side of the fourth left finger. A 31-year old, right dominant hand man presented with a 15 years history of progressively growing “sausage-like swelling” of the finger. There was an inamovible, painless mass with restriction of the DIP and PIP joints range of motion, without skin lesion, redness or stiffness. Imaging showed a large non-agressive mass within the tendon sheath. We realized a complete excision of the mass. Histopathological examination showed synovial villus with body rice shape and central necrosis evoking tuberculous synovitis or reumatoid arthritis. However, there was no argument for mycobacterial infection nor rheumatoid pathology. Rice bodies mostly evoke chronic synovitis or arthritis in northern countries, but may also be found in infectious diseases such as mycobacterial infections, related to chronic bursitis. No physiopathological mechanism has been formally identified (microinfarctions after intra-articular synovial inflammation and ischemia + de novo formation and progressive enlargement by fibrin + alteration in fluid viscosity and fibrinogen content of the synovial fluid). Different locations of rice bodies have been documented such as shoulder, knee, extensor tendon in the hand, wrist and carpal tunnel and flexor tendon sheath, but at the knowledge of the authors, this is the first reported case of digit flexor sheath rice body formation not related to inflammatory disease such as mycobacteria infection or rheumatoid arthritis. Differential diagnosis include synovial chondromatosis, pigmented villonodular synovitis, gout, sarcoidosis, systemic lupus erythematosus, chronic fungal infection and atypical mycobacterial infection, but the absence of suggestive complications, negative bacterial and fungal cultures, and laboratory test results, allowed us to assume the absence of classic etiology. In a case like ours, even less described than tuberculosis or arthritis, there is no established treatment standard. Despite the absence of associated systemic therapy, radical excision of the mass should provide definitive treatment. Therefore, prolonged observation will be necessary to confirm absence of recurrence with radical excision. Rice body formation should be better known as a muskulosqueletal form of mycobacterial infection or rheumatoid affection either by radiologists, surgeons and pathologists to provide optimal care for patients.