Islet Cell Tumor Arising from Heterotopic Pancreas in the Duodenum: A Case Report

that is lying outside its normal location and it lacks any anatomic or vascular connections with the pancreas. It is also described as pancreatic heterotopia, a term coined by Barbosa et al. (1) in 1946. The frequency of heterotopic pancreas has been estimated to be 1 case per 500 explorations of the upper abdomen or 0.6-13.7% of autopsies (2). Heterotopic pancreatic tissue may be found anywhere along the alimentary tract including the stomach, duodenum, small intestine, Meckel’s diverticulum and the biliary tract, and even in the lungs, umbilicus or fallopian tubes. Yet the most common site is the stomach and the pyloric canal. This lesion is usually asymptomatic; however, some patients have epigastric pain, upper gastrointestinal bleeding and occasional gastric outlet obstruction. In a few cases, the reported complications of heterotopic pancreas are pancreatitis, pseudocyst, cyst formation, insulinoma, adenoma and malignant transformation (3), but the exact rate of complications via a pathologic process hasn’t been identified and malignant transfomation is a rare finding. Furthermore, islet cell tumor arising from heterotopic pancreas in the duodenum is extremely rare; we found only one well documented case in our review of the literature, and this was a pathologic case report (4). In this report, we describe a case of islet cell tumor arising from a heterotopic pancreas in the duodenum, and we discuss the radiological presentation and the pathologic comparison.