Duct of Luschka diagnosed by sonography in a patient with bile duct carcinoma and intrahepatic bile duct dilatation.

The bile duct of Luschka (BDL) is an anatomic anomaly that is an important cause of bile leakage after bile duct surgery. We report a case of bile duct carcinoma with dilated BDL that was diagnosed by ultrasonography (US). An 83-year-old man presented with an obstructive jaundice. US on admission revealed the presence of a solid hypoechoic mass in the bile duct at the hepatic duct confluence and a branch of the bile duct, about 2-4 mm in diameter, distinct from the dilated right anterior hepatic duct slightly upstream of the tumor. This branch had a spiral structure, extended along the gallbladder bed on the surface of segment 5 (S5) of the liver, and emanated small branches that entered the hepatic parenchyma. There has been no previous report of delineation of BDL by preoperative US.