A 24-year-old male presented with an asymptomatic right perirenal cyst that was detected on ultrasound performed during a physical screening. Abdominal computed tomography showed a hypodense cystic mass between the liver and right kidney. Peristalsis of the cystic mass was observed via multi-phase CT scan, including plain scan, arterial phase, venous phase and delayed phase. The mass was completely resected by laparoscopy.