Neoplastic endocrine differentiation of pancreatic ductal adenocarcinoma in a metastatic lymph node: report of a case.

The occurrence of non-neoplastic, scattered endocrine cells in pancreatic ductal adenocarcinoma (DAC) is thought to be a general phenomenon. Conversely, neoplastic endocrine differentiation (NED) of pancreatic DAC is extremely unusual. We report a case of NED in a metastatic lymph node from pancreatic DAC. This case is distinct because the main tumor of the pancreas was composed purely of DAC without endocrine differentiation, and the NED was found in only one of four metastatic peripancreatic lymph nodes. To our knowledge, no other such case has ever been reported. The patient was a 61-year-old woman who underwent pylorus-preserving pancreaticoduodenectomy for pancreatic head cancer. Some authors reported that pancreatic DAC with endocrine differentiation was associated with a better prognosis than DAC without endocrine differentiation. However, more cases must be studied to investigate the impact of NED of metastatic lymph nodes in pancreatic DAC.