[Pancreas anulare as a rare differential diagnosis of duodenal stenosis in adulthood].

Annular pancreas is rare congenital malformation of the pancreas. In about 50% of the cases the malformation is asymptomatic until the third to fifth decade. We report on a 52-year-old male patient who presented with subtotal duodenal and gastric outlet stenosis. Duodenohemipancreatectomy (Whipple's procedure) was performed. The histological examination showed an annular pancreas with complicating inflammatory reactions (tryptic sialadenitis) of the pancreatic head causing additional obstruction. Annular pancreas should be taken into account as a possible cause of adult duodenal obstruction. Endoscopic retrograde cholangiopancreatography (ERCP) is the diagnostic modality of choice, and in combination with computed tomography the diagnosis can be obtained preoperatively in many patients. However, there are still patients in whom the diagnosis can finally be obtained only intraoperatively especially in cases where inflammatory pseudotumors or subtotal duodenal stenosis make ERCP impossible.