Figure 4. a. Magnetic resonance cholangiopancreatography (MRCP) showed the branch duct of the pancreas penetrating to the common bile duct (arrow) and dilated intrahepatic bile duct. b. Endoscopic retrograde cholangiopancreatography (ERCP) showed filling defect in the middle common bile duct (arrow), which consisted of mucus discharged from the fistula.