Abstract
INTRODUCTION: The 2010 World Health Organization classification of intraductal neoplasms of the pancreas includes intraductal tubulopapillary neoplasms (ITPNs) and intraductal papillary mucinous neoplasms, the latter being a rare and new concept. ITPN sometimes cause acute pancreatitis; therefore, distinguishing ITPN from idiopathic acute pancreatitis is important but challenging. PRESENTATION OF CASE: We present the case of a 72-year-old male who had recurrent pancreatitis for the past 2 years, his diagnosis was idiopathic acute pancreatitis. He was admitted to our hospital with severe acute pancreatitis and cholangitis due to intrapancreatic bile duct stenosis. After the treatment of cholangitis, contrast-enhanced computed tomography revealed a tumor at the pancreatic head. Endoscopic retrograde cholangiopancreatography (ERCP) showed stenosis of the main pancreatic duct and distal bile duct, and adenocarcinoma was detected using brush cytology of the bile duct stricture and pancreatic juice. The patient was diagnosed with invasive ductal carcinoma and pancreaticoduodenectomy was performed. Histopathological findings revealed dilation of the pancreatic duct, and proliferation of columnar cells and cuboid epithelial cells in the main pancreatic duct of the pancreatic head. Mucus production was poor, and immunostaining results revealed ITPN. The patient is alive and do not exhibit signs of recurrence for 12 months. DISCUSSION: ITPNs can cause acute pancreatitis, which can be challenging to preoperatively diagnose. ITPNs presenting as acute pancreatitis are rare, with reported only 5 cases. CONCLUSION: It is important to be keep in mind that there is a possibility of ITPN after diagnosis of idiopathic acute pancreatitis.