This case demonstrates a rare example of de Quervain tenosynovitis diagnosed on a CT scan. US and MRI are the main imaging modalities used to diagnose this entity, whereas plain film can help exclude other possibilities such as fracture, osteomyelitis or trapezio-metacarpal osteoarthritis. CT has limited interest in the workup due to its inferior soft-tissue contrast capabilities compared to US and MRI as well as radiation concerns.