Imaging findings of intraductal tubulopapillary neoplasm (ITPN) of the pancreas and literature review

Objective: To investigate clinicopathological features and the imaging findings of intraductal tubulopapillary neoplasm (ITPN), in order to improve the recognition and imaging diagnosis for ITPN. Methods: Five patients with ITPN confirmed by surgical pathology were retrospectively collected to analyze the imaging findings and clinic data in combination with relevant literatures. Results: Four patients presented as soft tissue masses growing in the lumen of pancreatic duct. In the four patients, the tumors showed iso-or mild hypo-density and no calcifications on unenhanced CT, mild hypo-or iso-intensity on T₁WI, mild hyper-and iso-or hypo-intensity on T₂WI, hyper-intensity on DWI, and hypointensity on the ADC map compared with surrounding pancreatic parenchyma. The long axis of the lesions were consistent with the long axis of the main pancreatic duct in the four patients. In one patient, the tumor showed multiple cystic lesions and irregularly thickened cystic walls and septa without calcification on CT/MRI. The enhancement of the intraductal solid masses and solid components were slightly delayed and lower than that of the surrounding pancreatic parenchyma in each phases on CT and/or MRI. ITPN could presented as 'the 2-tone duct sign' on CT/MRI, and 'the cork-of-wine-bottle sign' on MRCP. Conclusion: ITPN is rare, and its intraductal growth behavior can be considered as a typical feature. (authors)