A Case of Mixed Neuroendocrine-non-neuroendocrine Neoplasm with Dilatation of the Main Pancreatic Duct

Abstract

A 61 year-old man with a 6-month history of epigastric pain visited our hospital for close exploration and treatment. A computed tomography (CT) showed a 50×30 mm low density area at the pancreatic tail which was suggestive of pancreatic cancer. It also revealed the dilatation of the main pancreatic duct (MPD) at the pancreatic head, and intraductal tumors were detected in the main pancreatic duct at the pancreatic head by endoscopic ultrasonography. Fine needle aspiration for the pancreatic tail tumor exhibited atypical cells showing both phenotypes of the acinar and of the neuroendocrine. Since the cytological examination for the tumor in the main pancreatic duct at the pancreatic head obtained similar cells, total pancreatectomy was performed. Pathological diagnosis of the pancreatic tail tumor was mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) accompanied with intraductal polypoid growth (IPG) reached to the main pancreatic duct at the pancreatic head, and the main tumor showed higher activity with the Ki-67 score of 50%. Unfortunately, he was detected having multiple liver metastases 4 months after the surgery, and administration of everolimus was started. The recurrent disease progressed even after starting the treatment, and he died a year after the surgery. We report here an extremely rare case of MiNEN accompanied with IPG.