Mucin-hypersecreting bile duct tumor characterized by a striking homology with an intraductal papillary mucinous tumor (IPMT) of the pancreas.

BACKGROUND AND STUDY AIMS: The mucin-hypersecreting bile duct tumor, which closely resembles an intraductal papillary mucinous tumor (IPMT) of the pancreas, is rare, and its clinical features are not well known. We report our experience of nine patients with this type of tumor, and analyze the data in order to elucidate its clinicopathologic characteristics.

PATIENTS AND METHODS: Between 1995 and 1998, nine consecutive patients (four men, five women; mean age 54) who were diagnosed as having a mucin-hypersecreting bile duct tumor were enrolled in this study.

RESULTS: Recent or previous attacks of biliary pain and acute cholangitis were reported by most of the patients. Characteristics included a widely open ampulla of Vater with extrusion of mucin, and a diffuse dilated intrahepatic and extrahepatic bile duct with amorphous filling defects on cholangiogram. On cholangioscopic examination, a papillary mass or minute mucosal lesion was found in the dilated bile duct containing thick viscid mucin. Nine patients were referred for an operation, and curative resection was performed in eight of them. Using histologic examination, well differentiated adenocarcinoma in the background of benign hyperplasia and adenoma was documented in all patients except one, who showed pure adenoma.

CONCLUSION: The mucin-hypersecreting bile duct tumor can be characterized by a striking homology with IPMT of the pancreas in clinical, radiologic, and pathologic features.