Intraductal US findings of perihilar biliary obstruction caused by hepatocellular carcinoma

Background/Aim: Perihilar biliary obstructions caused by hepatocellular carcinoma (HCC) are rare and can be frequently misdiagnosed as cholangiocarcinoma on cholangiogram before histological confirmation. The aim of this study was to identify intraductal US (IDUS) features of HCC invading the perihilar biliary tree to differentiate from cholangiocarcinoma. Methods: Between 1998 and 2005, twelve patients (mean age; 61.2 years, men; 9) who underwent wire guided IDUS with suspicious malignant perihilar biliary obstruction had histological evidence of HCC. IDUS was performed with a catheter US probe (diameter, 2.0mm; frequency, 20MHz) via the transpapillary route. IDUS findings were retrospectively reviewed by consensus. Results: 1) IDUS was successfully performed in all patients, without sphincterotomy. 2) IDUS showed a completely filling, polypoid tumor without ductal wall change and tumor base in all patients. 3) The findings of a positive nodule in a nodule (75%), the smooth surface pattern (91.6%), and iso or low echogenicity (83.3%) were frequently associated with HCC invading bile duct. 4) Two of six patients underwent transpapillary fluoroscopic bile duct biopsy showed HCC on histologic examination. Conclusion: Intraductal US features may help in the differentiation of HCC from intraductal cholangiocarcinoma in the patients with perihilar biliary obstruction.