A wrist mass is rarely caused by a ruptured tendon in the forearm. The common pathologies are ganglia, tendon tenosynovitis, and giant cell tumors of tendon sheaths. Less common causes are nerve sheath tumors, vascular lesions, or an accessory muscle belly. The authors investigated a case of neglected ruptured flexor carpi ulnaris tendon that mimics a mass in the wrist. To the authors’ knowledge, this is the first case report in relevant literature. During investigation, the high-resolution musculoskeletal ultrasound suggested a soft tissue tumor or a ruptured flexor carpi ulnaris tendon. The magnetic resonance imaging scan indicated an accessory flexor carpi ulnaris muscle belly. The diagnosis of ruptured flexor carpi ulnaris tendon was confirmed by surgical exploration. This case indicates that ultrasound may be better suited than magnetic resonance imaging in evaluating a wrist mass for its accuracy, availability, and portability.
From the Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (C-LR, L-CW, Y-YH, F-SJ); and Department of Physical Medicine and Rehabilitation (C-LR, T-HY, T-HL) and Department of Orthopedics (L-CW), Shang-Ho Hospital, Taipei Medical University, Taipei, Taiwan.
All correspondence and requests for reprints should be addressed to Chi-Lun Rau, MD, Shuang Ho Hospital, Taipei Medical University, No. 291, Zhongzheng Rd, Zhonghe District, New Taipei City 23561, Taiwan.
Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.