A case of intraductal papillary mucinous neoplasms after recurrent acute pancreatitis.

We report a case of main pancreatic duct (MPD)-type intraductal papillary mucinous neoplasms of the pancreas (IPMNs), in whom diagnostic imaging modalities showed abnormal findings after 4 episodes of acute pancreatitis. The patient was 51 years old at his first admission for acute pancreatitis. He experienced two more episodes of acute pancreatitis, though repeated computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) showed no abnormality to explain the cause of the pancreatitis. After 3½ years from his first episode of pancreatitis, CT and endoscopic ultrasonography revealed pancreatic duct dilation of the pancreas head. Seven years after the first admission, a second ERCP and intraductal ultrasonography revealed a partially dilated MPD with papillary tumors. He underwent pancreaticoduodenectomy, and the pathological diagnosis was intraductal papillary mucinous adenoma with moderate atypia. This case suggests that acute pancreatitis can precede visualized IPMNs. Therefore, acute recurrent pancreatitis with unknown etiology should be followed up for the possibility of IPMNs, in order to detect neoplastic changes in the early stage to provide a better prognosis for the patient.