Sonographic findings from inflammatory arthritis due to antisynthetase syndrome

Inflammatory arthritis is a common feature of antisynthetase syndrome. Ultrasonography is able to characterize important features of bone and tendon pathology but has not been evaluated in this setting. We review the sonographic findings in a series of patients with antisynthetase syndrome and inflammatory arthritis. A retrospective chart review was performed of patients with antisynthetase syndrome-associated inflammatory arthritis who had undergone ultrasound imaging for joint pathology. Seventeen sonographic assessments of eight patients were included. Synovial hypertrophy was seen in all eight patients, with active Doppler signal present in six patients (13 of 17 ultrasound locations). Tendon involvement was common, with tenosynovitis in seven patients (11 of 17 ultrasound locations). Erosions were present in five patients. Musculoskeletal ultrasound showed significant joint pathology including proliferative synovitis and tenosynovitis. This may be severe and associated with erosive disease. Further systematic studies are needed to better understand the articular involvement of antisynthetase syndrome.Key points• Marked inflammatory change—with proliferative synovitis, tenosynovitis, and erosions—can be seen in selected patients with antisynthetase syndrome (ASyS).• Inflammatory arthritis from ASyS can be severe and erosive in the absence of RF and ACPA and can be refractory to immunosuppressive therapy used to manage the myositis and interstitial lung disease.• Systematic sonographic evaluation of patients with ASyS is needed to further evaluate pathology and treatment response of inflammatory arthritis.