Distinguishing benign from malignant intraductal papillary mucinous tumors of the pancreas by imaging techniques

Objectives: It is often difficult to differentiate benign from malignant intraductal papillary mucinous tumors (IPMTs). This study aimed to differentiate them using various imaging techniques. Methods: Receiver operating characteristic curves were used to establish optimal cutoff values to differentiate benign from malignant tumors in 121 patients with histologically confirmed IPMTs. Results: For branch duct type, accuracy for malignancy was highest using endoscopic ultrasonography (EUS) to measure the cyst diameter, and accuracy was 68.2% at a cutoff value of 33.9 mm. For main duct type, accuracy was highest, 71.1% at a cutoff value of 8.4 mm for main duct diameter, with magnetic resonance cholangiopancreatography. For all imaging techniques and findings, accuracy was highest using EUS, 76.4% at a cutoff value of 5.4 mm for height of protrusion. Each imaging technique had a positive predictive value of 80% if the cut off value for the height of the protruding lesion was met. Conclusions: Malignancy can be strongly suspected when the height of protrusion exceeds the respective cutoff values. EUS was most effective to differentiate benign IPMTs from malignant tumors by assessing the height of protrusion.