Hepatobiliary imaging of common bile duct obstruction by a hydronephrotic kidney.

A patient with intermittent right upper quadrant abdominal pain thought to represent acute cholecystitis had common bile duct obstruction due to an enlarged right renal pelvis. A Tc-99m-HIDA scan provided the first clue to the diagnosis. The case reinforces the value of cholescintigraphy in diagnosing pathology outside the biliary system.