Bicipital synovial cyst in poly-articular juvenile idiopathic arthritis

Abstract

Background: Large synovial cysts are rare in juvenile idiopathic arthritis ( JIA). They are usually located in popliteal area. Bicipital cyst is uncommon and has been described in systemic onset of JIA during an inflammatory attack. We describe the presentation and clinical course of bicipital synovial cyst occurring in patient with polyarticular subtype of JIA. In our knowledge, it's the first case reported.Case presentation: Our patient had an active disease with high level of biological inflammation. After ruling out the infectious origin of the cyst, the diagnosis was confirmed by ultrasonography revealing a liquid nature of the formation and magnetic resonance imaging showing the continuity between the shoulder's joint effusion and the cyst. A complete resolution was obtained 4 weeks after control inflammation using high dose of anti inflammatory drugs (prednisone 1mg/kg/d, indomethacin 3 mg/kg/d). Conclusion:Bicipital cyst is an unusual condition of JIA, extremely rare in polyarticular form. His etiology remains poorly understood. Our Patient had a high level of biological inflammation as in systemic subtype. The diagnosis is confirmed by ultrasonography. Magnetic resonance imaging may be helpful in case of doubt. The treatment is no specific and based on the control of the disease activity. Even though bicipital cyst is rare manifestation of JIA, it should be considered as a complication of active disease related to inflammatory phenomena.