A case of jaundice

This 25 year old man presented with an attack of jaundice. Here are photographs of his duodenal ampulla and EUS
WHAT IS THE DIAGNOSIS?

■ Impacted gallstone

There is more than just a bulging ampulla

■ Pancreas divisum

Nope!

■ Mass in the head of pancreas

But 'mass' seems to be extending below ampulla

■ Choledochal cyst

Of course, you do ERCP's clearly!

■ Duodenal varices

Looks a little vascular and would be soft to touch!

explanation

That EUS does confirm a cystic dilatation of the distal part of the common bile duct.   Of course, the patient has a 'choledochal cyst' !    These are congenital cystic dilatations of parts of the biliary tree. In this case, only the distal CBD was involved, making this a 'type III' choledochal cyst which is located at the ampulla (see figure below). 

Most cases presents as jaundice or pain in infants. Chronic cholestasis may present later with biliary cirrhosis or cholangiocarcinoma. 

Fortunately, this case was discovered before cirrhosis and the patient was treated with surgery.