Magnetic Resonance Imaging Spectrum of Solid Pseudopapillary Neoplasm of the Pancreas

Objective: To describe the magnetic resonance imaging spectrum of solid pseudopapillary tumors (SPTs), with an emphasis on solid SPTs. Methods: Thirty-two patients with proven SPTs with preoperative magnetic resonance were included. The SPTs were classified into 3 types: solid, cystic, and mixed; and 2 radiologists analyzed the images regarding the morphologic features and enhancement pattern. Results: Of 11 solid SPTs, 9 SPTs (81.8%) were less than 3 cm. Alternatively, of the 18 mixed SPTs and 3 cystic SPTs, 15 SPTs (71.4%) were larger than 3 cm. The predominant imaging features were homogeneous hypoenhancement with a gradually incremental enhancement pattern showing a sharp margin without hemorrhage, whereas those of the mixed SPTs were heterogeneous enhancement showing a sharp margin with internal hemorrhage. Conclusion: Solid SPTs frequently present as small, well-defined tumors with a gradual enhancement and without hemorrhage or necrosis, and with features that differ from those of mixed or cystic SPTs.