Intrapancreatic Accessory Spleen: Possibilities of Computed Tomography in Differentiation From Nonfunctioning Pancreatic Neuroendocrine Tumor

Objective: The aim of this study was to evaluate the ability of computed tomography (CT) in differentiating between intrapancreatic accessory spleen (IPAS) from pancreatic neuroendocrine tumor (PanNET). Methods: Eight IPASs and 12 PanNETs in the pancreatic tail were retrospectively evaluated by 2 radiologists. Readers assigned a diagnosis to each examination and evaluated for the presence or absence of 9 CT findings that may aid in the diagnosis. Results: Reader 1 had a sensitivity of 0.83 and a specificity of 1; reader 2 had a sensitivity of 0.78 and a specificity of 0.86. Three of the 9 CT findings were found to be statistically significant in IPASs: the lesion present along the pancreatic dorsal surface, the lesion demonstrating the same enhancement as the spleen on venous phase, and heterogeneous enhancement during arterial phase. Conclusions: CT can be used to differentiate between IPAS and PanNET with good specificity and sensitivity. The IPAS mirrors the spleen's enhancement and is usually located along the dorsal surface of the pancreas.