A 60-year-old woman was referred to our hospital with pancreatic cyst found by abdominal ultrasonography. Abdominal CT and MRCP demonstrated a multilocular cyst 30 mm in diameter in the pancreas head, without pancreatic duct dilation. Endoscopic ultrasonography demonstrated no mural nodule. The patient was diagnosed with branch duct intraductal papillary mucinous neoplasm (BD-IPMN) . After 12 years of follow-up, the enlarged cystic lesion up to 50 mm at the head of pancreas, dilated pa ncreatic duct up to 7 mm, and a contrast-enhanced mural nodule sized as 5mm in diameter in the cystic lesion were seen on CT scan. Pancreatic duodenectomy was conducted. Pathology showed an invasive pancreatic ductal carcinoma. This patient was diagnosed with an invasive cancer during a 12-year follow-up of BD-IPMN, which was successfully resected.
