Solid Pseudopapillary Neoplasms of the Pancreas: Imaging Differentiation between Benignity and Malignancy

To evaluate the clinical, pathologic, and imaging findings of solid pseudopapillary neoplasm (SPN) of the pancreas in order to differentiate benign from malignant pancreatic neoplasms.We retrospectively identified 23 patients with 24 SPNs confirmed by pathology at National Taiwan University Hospital between January, 2001 and March, 2012. All computed tomography and magnetic resonance imaging were reviewed by two radiologists in consensus. Each tumor was analyzed for location of tumor, tumor margin, proportion of solid component, capsule morphology, growth pattern, presence of calcification, presence of upstream pancreatic duct dilatation, and enhancement pattern.SPN of the pancreas demonstrated variable degrees of hemorrhagic degeneration and calcification. Focal discontinuity of capsule was consistently observed in five malignant tumors (p = 0.004). There were no statistical differences between benign and malignant tumors based on location of tumor, tumor margin, proportion of solid component, growth pattern, presence of calcification, presence of upstream pancreatic duct dilatation, or enhancement patternAmong the various imaging features, we found that focal discontinuity of the capsule may suggest malignancy.