An unusual cause of acute abdomen: mesenteric heterotopic pancreatitis causing confusion in clinical diagnosis.

Heterotopic pancreas is defined as the presence of pancreatic tissue that lacks anatomic and vascular continuity with the main body of the pancreas. Frequent symptoms and signs are epigastric pain, abdominal fullness and tarry stools. The most frequent locations of heterotopic pancreas tissue are the stomach and jejunum; however, there are a few reported cases of heterotopic pancreas in the mesentery of the small intestine. Heterotopic pancreas may or may not cause complications related to the pathologic conditions of the pancreas itself. Here we present a case showing an unusual cause of acute abdomen, which caused confusion in the clinical diagnosis preoperatively. The definitive diagnosis was achieved only after histopathologic examination in the postoperative period. Final diagnosis of the patient was mesenteric heterotopic pancreatitis, which was a complication of heterotopic pancreas itself with a rarely seen location. In conclusion, mesenteric heterotopic pancreatitis is seen very rarely and may be an unusual cause of acute abdomen. If the pathologic condition develops in the heterotopic tissue, as in the case of heterotopic pancreas, signs and symptoms of the disease may cause confusion in the clinical diagnosis. We agree that preoperative diagnosis of heterotopic pancreas is still difficult, even in a symptomatic patient.