Computed Tomography and Magnetic Resonance Imaging Findings of Malignant Solid Pseudopapillary Tumors of the Pancreas With Macroscopic Venous Tumor Thrombosis

Abstract

The purpose of this study was to report the imaging findings of malignant pancreatic solid pseudopapillary tumors (SPTs) with macroscopic venous tumor thrombi. The clinical features and imaging findings of 4 cases of malignant pancreatic SPT with venous tumor thrombi were retrospectively reviewed. The tumor thrombi were located in the splenic vein (n = 3) or the main portal vein and the proximal splenic vein (n = 1). Venous thrombi were connected with the main pancreatic tumors and showed venous filling defects on computed tomography and magnetic resonance imaging. Tumor thrombi primarily consisting of necrotic component and/or hemorrhage displayed no enhancement after contrast injection (n = 3). The enhancement pattern of the tumor thrombi that consisted mainly of tumor nests was consistent with pancreatic SPT (n = 1), that is, a slight enhancement in the arterial phase and a progressive enhancement in the portal venous phase and the equilibrium phase. Venous tumor thrombi associated with hemorrhage were hyperintense on both T1-weighted and T2-weighted images. It is uncommon for pancreatic SPTs to spread by invading the venous system and forming macroscopic venous tumor thrombi.