2025 Volume 39 Issue 4 Pages 645-651
A 75-year-old man presented with epigastric pain and sought care at a previous hospital. Jaundice and increased levels of serum hepatobiliary enzymes and tumor marker were noted, leading to his referral to our hospital. Contrast computed tomography revealed a mass with contrast enhancement in the distal bile duct, along with wall thickening extending from the mass to the confluence of the cystic duct. A 16-mm multilocular cystic lesion was observed in the pancreatic head; however, no significant enhancement was observed. Magnetic resonance imaging showed the mass with a hyperintense signal on diffusion weighted imaging and a low signal on the apparent diffusion coefficient map. Cholangioscopy revealed a papillary mass in the distal bile duct; however, the biopsy result did not show malignant features. We suspected distal bile duct cancer with branched intraductal papillary mucinous neoplasm (IPMN). A subtotal stomach-preserving pancreaticoduodenectomy was performed. Histopathological examination of the specimen showed a papillary and irregularly growing tumor; the specimen was diagnosed as IPNB with associated invasive carcinoma, pT1N0M0, pStage I. The cystic lesion in the pancreatic head was diagnosed as branched IPMN.
