Secondary Neoplasms

1. Pathogenesis:

• Secondary neoplasms may cause biliary obstruction. Possible sources include (top to bottom):
   
• Hepatocellular carcinoma.
   
• Pancreatic carcinoma.
   
• Ampullary tumor: occur at the ampulla of Vater and originate from the bile duct, pancreas, or duodenum.
   
• Periampullary duodenal tumors.

2. Radiographic findings:

• Hepatocellular carcinoma
   
• Radiographic findings can be found in the liver section.
   
• Pancreatic carcinoma
   
• US: in 95% of cases, a low echogenicity mass is shown causing bile duct obstruction.


Note hypoechoic mass ahead of pancreas (arrow).

• On CT, the following will likely be apparent: bile duct and pancreatic duct dilation (double duct sign); abrupt, focal, irregular stricture of the common biliary duct; bile duct encasement by direct extension or metastasis to peribiliary nodes.


CT shows pancreatic head mass (arrow).

• The diagram below shows a typical appearance of pancreatic carcinoma on ERCP.



• Ampullary tumor
   
• Biliary dilation is seen proximal to the tumor.
   
• Figures: Choledocholithiasis and ampullary carcinoma. (A) ERCP shows stones floating in the lumen of the common bile duct and tumor protruding from the wall of the distal common bile duct (arrow).


A                                  

• (B) CT shows dilated intrahepatic bile ducts due to common bile duct obstruction. (C) CT shows tumor surrounded by contrast material in dilated distal common bile duct (arrow).

        
B                                                                     C