2026 Volume 68 Issue 8 Pages 1411-1417
A 56-year-old man was found to have a tumor in the pancreatic tail following an episode of acute pancreatitis. MRI revealed a 20-mm cystic lesion communicating with the main pancreatic duct, with a solid component inside. Contrast-enhanced CT and contrast-enhanced endoscopic ultrasonography (EUS) demonstrated that the solid component had an enhancement similar to that of the surrounding pancreatic parenchyma. Endoscopic retrograde cholangiopancreatography (ERCP) revealed a cystic lesion continuous with the main pancreatic duct, without evidence of mucus production. Brush cytology of the main duct near the cyst revealed Class Ⅳ atypia. Based on the preoperative diagnosis of intraductal tubulopapillary neoplasm (ITPN), the patient underwent surgical resection. However, the final pathological diagnosis was an intraductal oncocytic papillary neoplasm (IOPN). IOPN is often asymptomatic, and cases associated with acute pancreatitis are extremely rare. Mucin-poor intraductal neoplasms of the pancreas include IOPN, ITPN, and the pancreatobiliary type of intraductal papillary mucinous neoplasm (IPMN), all of which are often difficult to distinguish preoperatively. A comprehensive understanding of the clinicopathological characteristics of these tumors is essential for their accurate diagnosis and management.
