Tuberculous synovitis of the elbow joint.

Tuberculous synovitis in the elbow joint is extremely rare in developed countries. We describe a 68-year-old man who had had a gradually enlarging mass over the volar side of the left proximal forearm near the elbow joint for 4 months. Plain roentgenograms of the diseased elbow showed early osteoarthritic change. Magnetic resonance imaging revealed diffuse synovitis with a large 8 x 8 cm extra-articular synovial cyst. Synovectomy was performed and histopathologic examination of the surgical specimen revealed granulomatous inflammation with caseation, prominent Langhan's giant cells, and sparse acid-fast bacilli. The patient had been receiving antituberculous chemotherapy for at least 8 months at the time of examination and had no recurrence of swelling or discharging sinuses during follow-up. Differential diagnoses in patients with elbow swelling should include pigmented villonodular synovitis, hemophilic arthropathy, rheumatoid arthritis, degenerative joint disease, and tuberculosis. Simple aspiration may enable earlier diagnosis, before destructive arthropathy becomes advanced.