A case of pancreatobiliary-type intraductal papillary mucinous neoplasm with associated invasive carcinoma of the pancreas showing unexpected intraductal extension along the main pancreatic duct

Abstract

Intraductal papillary mucinous neoplasms (IPMNs) are classified into three subtypes: gastric, intestinal, and pancreatobiliary, of which the pancreatobiliary type is the least common and has the highest malignancy potential. This report deals with the unique case of a 75-year-old woman with pancreatobiliary-type IPMN. Endoscopic ultrasonography which revealed a 15mm elevated lesion in the main pancreatic duct of the pancreatic head and a nodule measuring 3mm in the caudal direction. A pancreatoduodenectomy was performed, including the smaller nodule, and the intraoperative diagnosis of the cut-end margin of the pancreatic body revealed a high-grade IPMN in the main pancreatic duct, requiring a total pancreatectomy. The pathological diagnosis of the resected specimens revealed a pancreatobiliary-type IPMN with a maximum diameter of approximately 15mm filling the main pancreatic duct of the pancreatic head with an associated invasive carcinoma. In addition, atypical epithelium extended along the main pancreatic duct toward the pancreatic tail, for a total IPMN length of approximately 9cm. As this case illustrates, because pancreatobiliary-type IPMNs in the main pancreatic duct may show unexpected intraductal extension, it is necessary to pay close attention to the extent of resection based on an intraoperative diagnosis.