Searching for Indicators of Malignancy in Pancreatic Intraductal Papillary Mucinous Neoplasms: The Value of 18FDG-PET Confirmed

Malignancy in intraductal papillary mucinous neoplasms (IPMN) of the pancreas may be predicted on the basis of a number of clinical and radiologic features, which have raised sensitivity but result in a specificity as low as 20-50%. We sought to confirm the additional value of F-18-18-fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) in diagnostic accuracy of imaging-based IPMN malignancy assessment. This prospective uncontrolled case series contained 44 patients with IPMN undergoing comprehensive diagnostic evaluation, including magnetic resonance cholangiopancreatography and (18)FDG-PET. Average follow-up time was 39.3 months (range 3-97 months). Diagnostic performance regarding the diagnosis of malignancy was evaluated for the classic preoperative assessment, including clinical signs, CA 19-9, imaging (computed tomography and magnetic resonance cholangiopancreatography), and International Consensus Guidelines criteria, as well as (18)FDG-PET scan. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 100, 22, 32, 100, and 43%, and 83, 100, 100, 94, and 96%, respectively, for comprehensive assessment without and with (18)FDG-PET [maximum standardized uptake value (SUVmax) cutoff of 2.5 MBq]. Elevated CA 19-9 values and positive PET scan were the only independent prognostic factors for malignancy (odds ratio 2.11, 95% confidence interval 1.15-2.74 and 5.49, 95% confidence interval 3.98-21.44, respectively). (18)FDG-PET is useful for detection of malignancy in IPMN, improving the differential diagnosis with benign cases by functional data. The choice of SUVmax cutoff should maximize specificity.