Intraductal papillary mucinous neoplasms of the pancreas: making a disposition using the natural history.

The process of Intraductal papillary mucinous neoplasms (IPMN) follows the adenoma-to-carcinoma sequence. If it progresses to malignancy about 5 years is required. Even though the process is slow IPMN provides the clinician with the opportunity to avoid malignancy if the patient is at risk. The natural history as observed through Kaplan Meier event curves for occurrence of malignancy show the process to malignancy is much faster (50% within 2 years) if pancreatitis-like symptoms are present or if the main pancreatic duct (MPD) is involved. Almost all decisions to resect (95% in our experience) are based on the presence of symptoms or the MPD location. Cyst size is used infrequently. Every patient with an IPMN should always have a planned follow-up and the frequency depends on the perceived risk of malignancy-immediate imaging if becomes symptomatic to every 2 to 3 years if asymptomatic side branch lesions. The natural history provides modern guidelines for making decisions in patients with a newly discovered IPMN.