Ultrasound findings in AL musculoskeletal amyloidosis

Systemic AL amyloidosis is one of the differential diagnosis of chronic musculoskeletal disease, especially when swollen and painful joints is associated with claw hands. Ultrasound evaluation is a good diagnosis tool, showing a characteristic joint and tendon involvement and assisting in guided biopsy procedure. We report a 55 year old caucasian woman, diagnosed for two years with RA without improvement under different DMARDs, admitted for fixed flexion contractures of both hands ("claw hands"), worsening pain and swelling of small joints of hands and feet, elbows and shoulders. Pad shoulder sign and bilateral anterior wrist and elbow pads, macroglossia, thickened skin of fingers and ecchymotic rashes on forearm and around eyes were observed. Ultrasound examinations showed subdeltoid and bicipitoradial bursitis, presence of inhomogeneous hypoechoic material around bicipital tendons and tenosinovitis of the extensor tendons of the hand, and synovial thickening of elbow and shoulder joints. Complete analysis of the bone marrow biopsy and biopsy specimens from subacromial bursa were positive for AL amyloidosis.