Solid-Pseudopapillary Tumor of Pancreas: MR Imaging features and their correlation with pathological findings

Abstract

Objective To describe the MRI features and pathologic findings of solid-pseudopapillary tumor of the pancreas(SPTP) to assess the diagnostic value of MRI in this disease. Methods MR images and pathologic findings of 8 patients who underwent surgery for SPT between January 2005 and June 2007 in our hospital were retrospectively analyzed. Results All 8 cases demonstrated solitary solid-cystic masses. The tumors in 4 cases were located in the pancreatic head, 1 in the pancreatic neck and 3 in the tail. Of the 8 cases, the maximal diameter of 6 tumors was larger than 5 cm, only 2 tumor was 1.6 cm and 2.2 cm in diameter, respectively. On MRI, 8 tumors presented as heterogeneous intensity with solid and cystic component. Six mainly contained solid components and the other 2 cystic components. After contrast administration, the solid parts of the lesions showed slight enhancement during arterial phase and gradual progression during portal vein phase and delay phase. But the cystic parts of the lesions were homogeneous in signal intensity and showed no enhancement.Six of the 8 cases demonstrated hemorrhage within tumors showing hyperintensity on T1WI. In 5 of the 8 cases, the discontinuous speudocapsules were detected and the tumors invaded the adjacent structures. The invasion of mesocolon was detected in 3 cases during operation, the wall of duodenum was invasive in 2 cases and superior mesenteric vein was invasive in 2 cases. The common bile duct and pancreatic duct dilated in 2 cases. Accurate preoperative diagnosis was made in 7 cases whereas 1 case was misdiagnosed as gastrointestinal stromal tumor. Conclusion MR imaging can reveal the characteristic features of SPTP and is helpful for accurate preoperative diagnosis. Key words: Pancreas neoplasm; Magnetic resonance imaging; Pathology