Ectopic pancreatic tissue, also known as a pancreatic rest, is an uncommon congenital anomaly defined as extrapancreatic tissue located far from the pancreas and without any connection via vascular or anatomical means to it. Such tissue may occur throughout the GI tract but has a propensity to affect the stomach and the proximal small intestine. The majority of patients with pancreatic ectopia are asymptomatic, but when symptoms occur, they can be presented in a variety of ways. We report a patient with acute surgical abdomen due to a duodenal perforation caused by inflammation of ectopic pancreatic tissue in duodenum and stomach. Histology of the resected duodenum and stomach demonstrated heterotopic pancreatic tissue acute inflammation without atypia, suggesting "pancreatitis of the duodenum and stomach". To date, there have been a few reports describing perforation of the stomach due to heterotopic pancreas. Therefore, the present case was considered to be a very rare case of this disorder. To conclude, heterotopic pancreas should always be considered in the differential diagnosis of acute abdomen.