Figure 26a. Ductal cholangiocarcinoma in a patient with preexisting sclerosing cholangitis. (a) Axial US scan through the porta hepatis shows a thick-walled common bile duct (diameter, 2.2 cm) with an indwelling stent. (b) Axial US scan through the porta hepatis obtained 3 months later shows marked enlargement of the common bile duct (diameter, 3.1 cm). Cholangiocarcinoma was proved at histopathologic analysis. Cross-hatch calipers in each image indicate the lateral margins of the duct.