Annular pancreas and obstructive jaundice.

Annular pancreas is a rare abnormality which, in some cases, will be an incidental finding. Recently, two case reports have highlighted the possibility that annular pancreas is responsible for extrahepatic biliary obstruction in the absence of pancreatitis. We present a case of obstructive jaundice in which an annular pancreas was noted at both ERCP and CT scanning, but in which the cause of the obstruction was a carcinoma of the ampulla of Vater. Obstructive jaundice should not be attributed to an annular pancreas until the alternative differential diagnoses have been positively excluded.