Incidental pancreatic cysts on 3D turbo spin echo MRCP: prevalence, and relation with clinical and imaging fatures.

PURPOSE: To estimate the prevalence of pancreatic cysts (PCs) in a population of patients addressed to Magnetic Resonance Cholangiopancreatography (MRCP) for disease unrelated to the pancreas, and to analyze it with respect to clinical and imaging features. MATERIALS AND METODHS: MRCPs performed over a 2-years period on 156 patients with unsuspected/unknown pancreatic disease were retrospectively reviewed to assess: PCs presence, number, size, location (head/body/tail), relation with the main pancreatic duct (close vs. far; communicating vs. non communicating), and evolution in patients who underwent follow-up examinations. Multiple logistic regression analysis was performed to evaluate the correlation of PCs with clinical information (age, sex, history of neoplasm or autoimmune biliary disease, presence of hepatic and/or renal cysts) and type of pancreaticobiliary findings at MRCP. RESULTS: Prevalence of PCs was 43.6%. Cysts ranged in size from 3.0 to 53 mm (mean, 6.7 mm), and were equal or less than 4 in number in 83.8% of patients. Based on number and relation with the main pancreatic duct, PCs were classified as intraductal-papillary-mucinous tumor (IPMT)-like lesions in 70.6% of patients with cysts, and as indeterminate lesions in further cases. During the follow-up on 20 patients no evolution of PCs was found, except for one case with proven IPMT showing increase in cysts number and dimensions. Features correlating with PCs at the multivariate analysis (p<0.01) were age ≥60 years-old, and history of autoimmune biliary disease, showing odds ratios of 4.78 (95%C.I. 2.31-9.91) and 0.18 (95%C.I. 0.05-0.60), respectively. CONCLUSIONS: PCs represent a frequent incidental finding at MRCP, correlating positively with increasing age, and negatively with hepatobiliary autoimmune disease. An IPMT-like pattern was present in the large majority of patients.