Bilateral thenar hammer syndrome

Background: Thenar hammer syndrome is a very rare condition that mimics rheumatic diseases such as carpal syndrome tunnel, Raynaud's phenomenon, and hand synovitis. Objective: To describe the sonographic presentation of thenar hammer syndrome in a typical patient. Methods: Grey-scale sonography and colour Doppler imaging of the hands with an iU22 scanner (Philips) were performed. Results: In B mode, the lesion was seen as a large, rounded, heterogeneous area combining hypoechoic and echogenic components. Pseudoaneurysm was diagnosed based on presence of a cystic saccular formation arising directly from the adjacent artery and exhibiting an irregular thick wall with turbulent blood flow in the lumen. Colour Doppler showed blood flow in part of the lumen, the rest of which was filled with a thrombus seen as echogenic tissue. Conclusion: Sonography can help to diagnose thenar hammer syndrome. Angiography may be unnecessary in patients with normal colour Doppler findings. © 2010 Société française de rhumatologie.