Intraductal Papillary Mucinous Tumor of the Pancreas

Intraductal papillary mucinous neoplasm (IPMN) also known by its unified term Intraductal papillary mucinous tumor (IPMT), are rare cystic neoplasms of the pancreas formed of papillary proliferations of mucin-producing epithelial cells with or without excessive mucus production and/or cystic dilation of the pancreatic duct. Most commonly, it has been described in individuals between 60 and 80 years, regardless of age. Majority of IPMNs are located in the pancreatic head (75%) whereas the rest involves the body/tail regions. Patients often present with recurrent abdominal pain, due to intermittent obstruction of the pancreatic duct by mucin head. IPMNs are classified into 3 types: Branch duct, Main duct, and Mixed IPMN. Branch duct type lesions demonstrate a macrocystic or microcystic pattern, involves the dilation of side branches and manifest as grape like clusters arising from main pancreatic duct (MPD). Main duct type involves the MPD, may be diffuse or segmental and are more prone to malignancy. Mixed type involves the dilatation of the main duct and the branch ducts of the uncinate process. The cross sectional imaging such as CT or MRI features includes presence of a cystic mass, MPD dilatation especially downstream in the main type. MPD is usually normal or slightly dilated and appears as round or oval, small, clustered cystic masses in the branch type. Predictive factors of malignant IPMN includes history of diabetes, alcohol abuse, male sex, large tumor size, mural nodularity > 5mm, dilatation of MPD > 10 mm, thickened cystic wall and internal septae. Endoscopic Retrograde Cholangiopancreatography (ERCP) represents the standard of reference for diagnosis of IPMN, often limited due to inadequate delineation of pancreatic duct because of limited opacification and also intraductal papillary excrescences that may prevent full ductal evaluation. MR imaging is considered superior to ERCP, given the ability of MR imaging to reveal the full extent of ductal involvement, particularly when obstructing mucus prevents diagnostic opacification of the entire duct. Differential diagnosis of main duct type IPMN includes chronic pancreatitis. The dilatation of MPD and presence of mural nodules favors IPMN. Branch duct IPMN must be distinguished from mucinous and serous tumors of the pancreas based on communication of the pancreatic duct with the lesion that favors IPMN. IPMNs should be completely excised for a good prognosis. The extent of pancreatic resection is decided based on imaging studies. Typical resections, such as pancreatoduodenectomy, distal pancreatectomy along with splenectomy, or total pancreatectomy, are performed for malignant cases. The reported case was histopathological confirmed to be IPMN with moderate dysplasia.