Mucin-Secreting Bile Duct Adenoma – Clinicopathological Resemblance to Intraductal Papillary Mucinous Tumor of the Pancreas

We describe a case of mucin-secreting biliary adenoma associated with obstructive jaundice due to mucin production. Duodenal endoscopy revealed mucin secretion through an enlarged papilla of Vater. On the cholangiogram, large filling defects caused by mucin were observed in the dilated bile duct. Granular and/or papillary mucosa was noted from the hilar to the common bile duct by using percutaneous transhepatic cholangioscopy. Biopsy specimens taken from the papillary mucosa revealed slightly papillary projection without any evidence of malignancy. This lesion was diagnosed as mucin-secreting superficial adenoma and pancreatoduodenectomy was performed according to the malignant behavior. Using a histologic examination of the specimen, pure adenoma was documented. Since the surgical margin was positive, radiation was added for the residual adenoma in the intrahepatic bile ducts. The patient has been well without any evidence of recurrence for 21 months since her operation. It is only recently that the term ‘intraductal papillary mucinous tumor (IPMT)’, which is accepted as a distinct disease entity of pancreas, has begun to be used for mucin-secreting bile duct tumor. This case also seemed to clinicopathologically resemble an IPMT of the pancreas.