Intrapancreatic accessory spleen.

Accessory spleens are common, usually asymptomatic, incidentally discovered congenital foci of splenic tissue. They occur most commonly near the splenic hilum, with almost 20% in or near the pancreatic tail. On contrast-enhanced computed tomography (CT), differentiation of an intrapancreatic accessory splenule (IPAS) from other pancreatic tail lesions such as islet cell tumors and metastatic disease can present a diagnostic challenge. A high index of suspicion on the part of the radiologist, based on the classic location with typical imaging features and a combination of cross-sectional imaging studies such as ultrasound, computed tomograph (CT), or magnetic resonance imaging (MRI) with nuclear medicine examinations, can confirm the diagnosis of intrapancreatic accessory splenule and prevent unnecessary biopsy and/or surgery.