A resected case of intraductal tubulopapillary neoplasm of the pancreas: report of a case.

The patient was a 61-year-old male who was referred to our hospital after dilatation of the main pancreatic duct was detected by screening ultrasonography. Computed tomography revealed a protruding lesion measuring 15 mm in diameter within the main pancreatic duct in the head of the pancreas, and magnetic resonance cholangiopancreatography revealed interruption of the duct at the tumor site. We performed pancreaticoduodenectomy under a suspected diagnosis of invasive ductal carcinoma. Gross examination of the resected specimen showed that the tumor invaginated into the main pancreatic duct, and no mucin was found. Histological examination revealed proliferation of high-grade dysplastic cells in a tubulopapillary growth pattern. Immunohistochemically, cytokeratin 7 expression was detected, but not trypsin expression. Based on these morphological features, we diagnosed the tumor as intraductal tubulopapillary neoplasm (ITPN). We report the case with bibliographic consideration, together with a review of intraductal neoplasms of the pancreas encountered at our institution.