Figure 1: Serial coronal reformatted contrast-enhanced CT through upper abdomen. (a) Pre-treatment image shows mildly enlarged liver and normal common bile duct (diameter 7 mm) (arrow). (b and c) CT done immediately before discontinuation of pembrolizumab shows dilated common bile duct (15 mm) (solid arrow in b) with wall enhancement. Gallbladder shows wall edema (open arrow). Central intrahepatic bile ducts are also dilated (arrow in c). (d) CT done approximately four months later shows persistent dilatation of common bile duct (arrow)