A case of high-grade pancreatic intraepithelial neoplasia diagnosed based on focal pancreatic parenchymal atrophy after acute pancreatitis

A 60-year-old male visited a previous hospital with upper abdominal pain. He was diagnosed with localized mild acute pancreatitis. Three months later, abdominal contrast-enhanced computed tomography showed focal parenchymal atrophy of the pancreas with distal pancreatic duct dilation. No obvious solid mass could be found at the site of the pancreatic duct stenosis on imaging examinations. Endoscopic retrograde pancreatography showed focal mild stenosis with distal pancreatic duct dilation in the tail of the pancreas. Carcinoma in situ of the pancreas was strongly suspected, especially based on the presence of focal atrophy of the pancreas around the site of stenosis of the main pancreatic duct and the distal pancreatic duct dilation. Laparoscopic distal pancreatectomy was performed. Histologically, high-grade pancreatic intraepithelial neoplasia was found in the epithelium of the stenotic main pancreatic duct and its branches. This case suggests that localized acute pancreatitis and focal atrophy of the pancreas with distal dilation of the pancreatic duct could be important clinical manifestations of pancreatic carcinoma in situ.