Pancreatic fat content may increase the risk of imaging progression in low‐risk branch duct intraductal papillary mucinous neoplasm

Objective To identify risk factors of imaging progression (increase in cyst size or main pancreatic duct size, or a new mural nodule) in low‐risk branch duct intraductal papillary mucinous neoplasm (BD‐IPMN), including obesity‐related factors such as pancreatic fat content. Methods Our hospital databases were searched for patients who had completed health checkup, including upper abdominal magnetic resonance imaging (MRI) over 48 months (August 2012 to July 2016). Individuals with BD‐IPMN without worrisome features and high‐risk stigmata who underwent surveillance with at least one follow‐up MRI, irrespective of the follow‐up period, were included. Pancreatic computed tomography attenuation indexes were defined as the difference between the pancreas and spleen attenuation (P ‐ S) and the pancreas to spleen attenuation ratio (P/S). Results Among 75 patients diagnosed as having low‐risk BD‐IPMN, during a median follow‐up of 36 months, 11 (15%) had imaging progression in cyst size, including two with worrisome features. A multivariate logistic analysis showed that the initial cyst size and both indexes (P ‐ S, or P/S) were significantly associated with imaging progression in IPMN, respectively (Model 1: odds ratio [OR] 1.188, 95% confidence interval [CI] 1.060‐1.331, P = 0.003; OR 0.871, 95% CI 0.776‐0.977, P = 0.019; Model 2: OR 1.186, 95% CI 1.064‐1.322, P = 0.002; OR 0.002, 95% CI 0.000‐0.970, P = 0.049). Conclusions Pancreatic fat content and initial cyst size were significantly associated with imaging progression in low‐risk BD‐IPMN. Revisions of international consensus Fukuoka guidelines might be customized based on initial cyst size and pancreatic fat content.