Tumor thrombus in the extrahepatic biliary tree is a rare mechanism of obst
ructive jaundice. We present a patient with a minute hepatocellular carcino
ma in the caudate lobe that invaded the common hepatic duct and caused bili
ary obstruction. Endoscopic sonography showed a tumor thrombus with central
echogenicity and a "nodule-in-nodule" pattern and suggested the correct di
agnosis. (C) 2001 John Wiley & Sons, Inc.