[A case of macroscopically unvisualized mucin-hypersecreting biliary papillomatosis diagnosed by microscopy].

The mucin-hypersecreting biliary papillomatosis is a premalignant neoplasm characterized by intraductal papillary proliferation involving extensive areas of the intrahepatic and/or extrahepatic bile duct. We report a case of mucin-hypersecreting biliary papillomatosis manifested as obstructive jaundice and diagnosed only by microscopy, with a review of literatures. A 74-year-old female, who had a past history of cholecystectomy about 13 years ago, was admitted to our hospital with jaundice. A CT scan showed marked dilatation of intrahepatic and extrahepatic bile duct without intraductal filling defect or extrabiliary mass. During endoscopic retrograde cholangiopancreatography, mucin extrusion from the duodenal major papilla and dilated common bile duct with amorphous filling defects was noted. Percutaneous transhepatic biliary drainage for cholangioscopy was failed. In the operation field, there was a lot of mucin but was no visible mass at the common bile duct with bare eyes and cholangioscopy. However, papilloma was detected at the random biopsy specimen by microscopy. The patient underwent partial resection of common bile duct and choledocho-jejunal anastomosis.