Biliary Giardiasis Presenting with Unique Image Findings of the Distal Bile Duct: A Case Report

A 79-year-old immunocompetent man was referred to our hospital due to elevated hepatobiliary enzyme levels. Imaging revealed shaggy homogeneous thickening of the distal bile duct with a common bile duct stone. Bile cytology revealed Giardia lamblia, leading to a diagnosis of biliary giardiasis. He had consumed well water contaminated with wild animal feces, which is considered a potential or suspected source of a G. lamblia infection. After stone removal and metronidazole monotherapy, the hepatobiliary enzyme levels normalized. Biliary giardiasis can occur even in immunocompetent individuals, and shaggy homogeneous thickening of the bile duct may be a noteworthy finding of biliary giardiasis.