Evolution of incidental branch-duct intraductal papillary mucinous neoplasms of the pancreas: A study with magnetic resonance imaging cholangiopancreatography

摘要

AIM To investigate the type and timing of evolution of incidentally found branch-duct intraductal papillary mucinous neoplasms(bd-IPMN) of the pancreas addressed to magnetic resonance imaging cholangiopancreatography(MRCP) follow-up.METHODS We retrospectively evaluated 72 patients who underwent, over the period 2006-2016, a total of 318 MRCPs(mean 4.4) to follow-up incidental, presumed bdIPMN without signs of malignancy, found or confirmedat a baseline MRCP examination. Median follow-up time was 48.5 mo(range 13-95 mo). MRCPs were acquired on 1.5T and/or 3.0T systems using 2D and/or 3D technique. Image analysis assessed the rates of occurrence over the follow-up of the following outcomes:(1) imaging evolution, defined as any change in cysts number and/or size and/or appearance; and(2) alert findings, defined as worrisome features and/or high risk stigmata(e.g., thick septa, parietal thickening, mural nodules and involvement of the main pancreatic duct). Time to outcomes was described with the Kaplan-Meir approach. Cox regression model was used to investigate clinical or initial MRCP findings predicting cysts changes.RESULTS We found a total of 343 cysts(per-patient mean 5.1) with average size of 8.5 mm(range 5-25 mm). Imaging evolution was observed in 32/72 patients(44.4%; 95%CI: 32-9-56.6), involving 47/343 cysts(13.7%). There was a main trend towards small( 0.01).CONCLUSION Changes in MRCP appearance of incidental bd-IPNM were frequent over the follow-up(44.4%), with relatively rare(8.3%) occurrence of non-malignant alert findings that prompted further diagnostic steps. Changes occurred at a wide interval of time and were unpredictable, suggesting that imaging followup should be not discontinued, though MRCPs might be considerably delayed without a significant risk of missing malignancy.