Accessory Spleen Masquerading as an Intrapancreatic Tumor: A Case Report.

The finding of splenic tissue within the pancreas, also known as splenosis or intrapancreatic accessory spleen (IPAS), is a relatively uncommon condition that presents as an intrapancreatic mass. The discovery of an intrapancreatic mass often prompts a thorough diagnostic workup for a primary pancreatic malignancy, often exposing patients to unnecessary risks associated with invasive testing and even surgery. The benign, asymptomatic nature of this finding places emphasis on utilizing non-invasive techniques for confirmation of the diagnosis, reducing risks of morbidity and mortality in this patient population. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) will display near-identical signal intensities (SI) between the spleen and the intrapancreatic mass, as well as identical contrast-enhancement patterns. Nuclear medicine evaluation with Tc-99m heat-damaged red blood cells (HDRBCs) is often used as a confirmatory test and allows for differentiation from malignancies.