Abstract
We report a rare case of intraductal papillary mucinous neoplasm (IPMN) accompanied by branch fusion between the ventral and dorsal pancreatic ducts. A 50-year-old man was admitted for evaluation of a dilated pancreatic duct in the pancreatic head. MRCP showed a dilated and winding pancreatic duct of the pancreatic head with a unique shape and dilated cystic branch, compatible with a diagnosis of branch type IPMN. After 2 years of observation, MRCP showed the dilatation of the cystic lesion of the branch duct to a diameter of 32 mm. The pancreatic cyst included a defect of signal intensity suggestive of an elevated malignant tumor, for which a pylorus-preserving pancreaticoduodenectomy was performed. Pancreatography of the resected specimen showed communication of the dorsal pancreatic duct with the ventral pancreatic duct through a corresponding lower branch. In Japan this type of incomplete fusion of the pancreatic duct is classified as “Branch fusion type II” by Hirooka. On pathology an intraductal papillary mucinous carcinoma (IPMC) with micro-invasion was diagnosed. The imaging of the branch fusion of the pancreatic duct obtained in this case is very unique.
