A case of asymptomatic intraductal papillary neoplasm of the bile duct without hepatolithiasis

Figure 1 A: Abdominal ultrasonography (US) of the liver showing slight dilatation of bile ducts in the right liver (S5); B: Contrast-enhanced CT scan of the abdomen showing markedly dilatation of bile ducts in the liver (S5). Solid masses were not observed.

Figure 2 Endoscopic retrograde cholangiopancreatography (ERCP) showing a biliary obstruction at the root of the hepatic duct, suggesting cholangiocarcinoma.

Figure 3 Cholangiography showing stricture of the bile duct (B5) and narrowness of bile duct (B8) in the right liver.

Figure 4 Macroscopic appearance of the resected right liver showing dilatation in the stump of the right intrahepatic duct, without a solid tumor component, which is surrounded by a fibrotic area.

Figure 5 Histopathological findings showing. A: A view of the intrahepatic bile ducts dilated with peri-ductal fibrosis (× 100); B: Carcinoma cells continuously proliferating from the intrahepatic large bile ducts to small bile ducts (× 400); C: Carcinoma cells continuously proliferating from the intrahepatic large bile ducts to small bile ducts (× 200); D: Carcinoma cells in bile ductules around the small portal area (× 200).

Figure 6 Immunohistological staining: MUC5AC, CK7 and CK20 are expressed in the tumor cells, whereas MUC1, MUC2 and p53 are not.