Pancreatic ductal adenocarcinoma concomitant with intraductal papillary mucinous neoplasm: a report of 8 cases.

Branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) is recognized as a risk factor for pancreatic ductal adenocarcinoma (PDAC) that is unrelated to the malignant transformation of IPMN. We experienced 8 cases of resected PDAC concomitant with IPMN from March 1988 to December 2012, and 7 patients had >2 risk factors, including IPMN, for pancreatic cancer. Seven of the IPMNs were <30 mm in size, while none had mural nodules. Four cases of PDAC were detected during the follow-up period for BD-IPMN. Neither magnetic resonance cholangiopancreaticography nor contrast-enhanced computed tomography performed 5 months prior to the detection of PDAC resulted in its early detection in 2 cases. The clinical features of the 8 cases indicate that particular attention is required for patients with >1 risk factor, in addition to IPMN, for pancreatic cancer. A shorter interval of surveillance than that suggested by the international consensus guidelines 2012 is required, even if the IPMNs are small, for the early detection of PDAC.