Among pancreatic cystic lesions, mucinous cystic neoplasm (MCN) and intraductal papillary mucinous neoplasm (IPMN) of the pancreas are precursor lesions of pancreatic adenocarcinoma. IPMN is characterized by intraductal papillary proliferation of mucin-producing epithelial cells that exhibit various degrees of dysplasia. IPMN is classified as the main duct type (MD-IPMN), mixed type and the branch duct type (BD-IPMN) according to the location of involvement, and into four histological subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) according to the histomorphological and immunohistochemical characteristics. Most patients with MD-IPMN undergo tumor resection due to moderate to high risk of malignancy. Patients with BD-IPMN who do not undergo resection may develop malignant change, and concomitant separate pancreatic cancer occurs in 2-10% of patients with IPMN. Patients with BD-IPMN who do not undergo resection should do careful surveillance including endoscopic ultrasound sonography for the early detection of malignant change and separate pancreatic cancer.