A case of benign intraductal papillary mucinous neoplasm of the pancreas containing two major subtypes.

Here we report a case of benign intraductal papillary-mucinous neoplasm (IPMN) of the pancreas containing two major subtypes. A 73-year-old man underwent pancreatoduodenectomy for a cystic mass, 5.0 cm in diameter. Histopathologic examinations revealed that IPMN was composed of gastric-type adenoma and intestinal-type borderline lesion. Marked intraluminal nodular growth was observed in the center of the tumor composed of intestinal-type cells positive for MUC2. Our observations suggest that gastric-type epithelium is a precursor of intestinal-type lesions in the stepwise progression of IPMN.