Comparison of F-18-FDG PET/CT findings between pancreatic solid pseudopapillary tumor and pancreatic ductal adenocarcinoma

Abstract

ObjectivePancreatic solid pseudopapillary tumor (SPT) is a rare benign tumor. Little data are available on positron emission tomographic/computed tomographic (PET/CT) characteristics of this tumor. Therefore, we analyzed the metabolic characteristics of SPT using F-18-FDG PET/CT and compared the results with those of pancreatic ductal adenocarcinoma. MethodsWe retrospectively reviewed the records of 11 SPT patients and 46 patients with ductal adenocarcinoma. Ten SPT patients had primary tumors and 1 patient had metastatic SPT. Maximum standardized uptake value (max SUV), mean SUV, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor-to-background ratio (TBR) were evaluated. Mann–Whitney U test between pancreatic SPT and ductal adenocarcinoma was performed. In addition, age, gender and tumor size-adjusted analysis of covariance (ANCOVA) was done between pancreatic SPT and ductal adenocarcinoma. ResultsCompared with pancreatic ductal adenocarcinomas, SPTs had significantly higher tumor size-adjusted MTV and TLG. MTV and TLG values were significantly correlated with T-stage of the SPTs. In 1 SPT patient, metastases in the liver and mesentery were revealed by intense uptake of FDG on F-18-FDG PET/CT, and after PET/CT had suggested the presence of pancreatic SPT. ConclusionWe recommend that SPT be considered when a solid pancreatic mass with increased FDG metabolism is encountered on PET/CT. F-18-FDG PET/CT may be useful in detecting subtle metastases of SPT.