Intraductal papillary mucinous neoplasms of the pancreas (IPMNs) are potentially malignant intraductal epithelial neoplasms that are grossly visible (>1 cm) and are composed of mucin-producing columnar cells. The lesions show papillary proliferation, cyst formation, and varying degrees of cellular atypia [1,2].
IPMNs may involve the main pancreatic duct, the branch ducts, or both. Whereas patients with branch duct lesions are at lower risk for developing malignancy (approximately 20 percent at 10 years), patients with IPMN involving the main duct are at high risk (approximately 70 percent). As a result, these lesions need to be accurately diagnosed and characterized so that appropriate treatment can be recommended. (See "Pathophysiology and clinical manifestations of intraductal papillary mucinous neoplasm of the pancreas", section on 'Classification' and "Pathophysiology and clinical manifestations of intraductal papillary mucinous neoplasm of the pancreas", section on 'Pancreatic malignancy'.)
This topic will review the diagnosis and treatment of IPMNs. The pathophysiology and clinical manifestations of IPMNs and an overview of pancreatic cystic neoplasms are discussed separately. (See "Pathophysiology and clinical manifestations of intraductal papillary mucinous neoplasm of the pancreas" and "Classification of pancreatic cysts" and "Pancreatic cystic neoplasms".)
The differential diagnosis of intraductal papillary mucinous neoplasm of the pancreas (IPMN) includes chronic obstructive pancreatitis, mucinous cystic tumors of the pancreas, and, rarely, pancreatic ductal adenocarcinoma. (See "Classification of pancreatic cysts".)
Traditional abdominal ultrasound and computed tomography (CT) scanning often cannot distinguish IPMN from these entities. As a result, additional testing with endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP), endoscopic ultrasound (EUS), or pancreatoscopy is frequently required. None of these imaging modalities is conclusive, and each has advantages and disadvantages.