Medial indentation of the duodenal sweep by common bile duct dilatation.

The dilated common bile duct has long been recognized as a cause for a smooth, tubular impression across the duodenal bulb or immediate postbulbar duodenum. Only scattered references suggest that a smooth indentation on the medial aspect of the descending duodenum might also be due to an enlarged, tortuous common duct. Three cases of this condition are reported. The dilated common duct impression can mimic a pancreatic mass. While computed tomography, ultrasonography, or transhepatic cholangiography readily suggest the true diagnosis, potential pitfalls in patient management are possible when the first radiographic procedure is an upper gastrointestinal series.