Intraductal papillary mucinous neoplasms (IPMNs) are rare pancreatic tumors, accounting for less than 1-2% of all neoplasms of the pancreas. The main characteristic of IPMNs is their favorable prognosis, as these pre-malignant or malignant lesions are usually slow-growing tumors and radical surgery is frequently possible. According to the localization of the lesions, three different tumor types have been identified: the main-duct IPMN, the branch-duct IPMN and the mixed-type IPMN (involving both the main pancreatic duct and the side branches). IMPNs do not present pathognomonic signs or symptoms. The obstruction of the main pancreatic duct system may cause abdominal pain and acute pancreatitis (single or recurrent episodes). The tumor may be incidentally discovered in asymptomatic patients, particularly in those with branch-duct IPMNs. In clinical practice, any non-inflammatory cystic lesion of the pancreas should be considered as possible IPMN. Computed tomography, magnetic resonance imaging with cholangiopancreatography and endoscopic ultrasonography can localize an IPMN and assess its morphology and size. The choice between non-operative and surgical management depends on the risk of malignancy and on the definitive distinction between benign and malignant IPMNs. Main-duct IPMNs have a high risk of malignant degeneration, especially in older patients. The clinical and radiological features, as well as treatment and outcome, of eight patients with IPMN (five with main-duct, two with branch-duct and one with mixed-type) observed by the authors over the last ten years are presented.
Not all mixed-type intraductal papillary mucinous neoplasms behave like main-duct lesions: Implications of minimal involvement of the main pancreatic duct