A Case of Primary Carcinoma in the Cystic Duct Detected by Intraductal Ultrasonography (Idus)

The patient, 68 years old, was admitted to our hospital complaining of epigastric pain and icterus. Percutaneous transhepatic cholangioscopy (PTCS) showed papillary tumor in the bile duct. Biopsy specimen through PTCS revealed adenocarcinoma. Intraductal ultrasonography (IDUS) and endoscopic ultrasonography (EUS) demonstrated a tumor in the cystic duct protruding into the common bile duct. In addition, IDUS showed that the tumor did not invade into the common bile duct, whereas EUS could only demonstrate main part of the tumor existing in the cystic duct and other part in the common bile duct with no evidence of invasion. IDUS was useful in the diagnosis of carcinoma occuring in the cystic duct.