[A case of metachronous invasive ductal carcinoma concomitant with intraductal papillary-mucinous neoplasm (IPMN) of the pancreas, which could not be detected in contrast-enhanced CT scan performed 3 months ago].

A 61-year-old man had been followed up in another hospital under diagnosis of branch duct type IPMN for 4 years. Contrast-enhanced CT scan for regular check performed 3 months ago revealed no increase of IPMN and no pancreatic tumor. However, he complained of back pain after that, MRI was performed. It revealed a solid tumor in size of 25mm diameter at the head of pancreas. The tumor was apparent from IPMN in several imaging modalities. Pancreatoduodenectomy was performed under diagnosis of invasive ductal carcinoma concomitant with IPMN. Post-operative pathological findings revealed IPMN was adenoma with mild atypia, and solid tumor was diagnosed invasive ductal carcinoma with solitary minute liver metastasis.