[A case of invasive micropapillary carcinoma of the pancreas concomitant with intraductal papillary mucinous neoplasm].

Invasive micropapillary carcinoma (IMPC), a rare subtype of adenocarcinoma, has a high incidence of lymph node metastasis and is associated with a poor prognosis. A 77-year-old woman was admitted to our hospital for the assessment of intraductal papillary mucinous neoplasm (IPMN). We diagnosed her with pancreatic cancer concomitant with IPMN and performed pancreaticoduodenectomy. The lesion was predominantly composed of ductal adenocarcinoma with a micropapillary component. On immunohistochemical analysis, a characteristic " inside-out pattern" was observed in the micropapillary component. This confirmed the diagnosis of pancreatic cancer with a micropapillary component. In the present report, we describe a very rare case of IMPC of the pancreas.