Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is subdivided based on the site of involvement within the main pancreatic duct (MPD) as follows: the main duct (MD), the branch duct, or a mixture of the two. Surgical resection is strongly recommended for MD-IPMNs because of their high malignant potential. In a previous surgical series, the malignancy rate of MD-IPMN was 36-100%. 1 However, this may be an overestimation of the actual risk. Surgical series can present selection bias, as patients who undergo surgical resection are more likely to present with criteria suspicious for progression.