Whenever there is bile duct dilatation, the first priority is to look for obstruction.
If there is an obstruction, we first look for gallstones in the bile duct. If there are no gallstones involved, we then look for strictures.
The differential diagnosis for a stricture is based on the location.
* A distal stricture is most likely the result of a distal cholangiocarcinoma, pancreatic carcinoma or pancreatitis.
* A stricture within the liver is likely due to gallbladder carcinoma or inflammatory strictures like PSC (Primary Sclerosing Cholangitis) or AIDS cholangiopathy.
* Metastatic disease can occur anywhere within the bilairy system.
Once we have excluded obstruction, we have to think about nonobstructive biliary diseases like:
* Caroli disease
* Choledochal cyst
* Recurrent pyogenic cholangitis
* Primary sclerosing cholangitis