Endoscopic and endoscopic ultrasound (EUS) features of annular pancreas: duodenal ulceration and a dilated bile duct.

Annular pancreas is a rare congenital anomaly in which a ring of pancreatic tissue encircles the secondpart of the duodenum [1]. Here we present the endoscopic findings in two patientswith annular pancreas, including the first endoscopic ultrasound (EUS) video to be published of the condition, illustrating the pancreatic duct coursing around the duodenum. Our first patient was a 70-year-old man who presented with severe anemia. Esophagogastroduodenoscopy showed narrowing of the second part of the duodenumwith ulceration and contact bleeding (●" Fig.1). Biopsies did not reveal any malignancy or evidence of Helicobacter pylori infection. Abdominal computed tomography (CT) showed a ring of pancreas encircling the duodenum (●" Fig.2). The patient was discharged with a prescription for omeprazole. At follow-up more than a year later, there was no outlet obstruction and the anemia had resolved. Magnetic resonance imaging (MRI) confirmed the presence of annular pancreas (●" Fig.3). Our second patient was a 59-year-old man with Ogilvie’s syndrome. Abdominal CT revealed a 15-mm dilated common bile duct (CBD) along with dilated bowel loops. Liver function tests were normal. Radial EUS evaluation of the biliary tree did not show any stone or stricture, but the pancreas and pancreatic duct were seen encircling the second part of the duodenum and merging with the distal CBD at the ampulla (●" Fig.4,●" Video1). The dilated CBD was attributed to the annular pancreas. Annular pancreas was first described by Tiedemann in 1818 and named by Ecker in 1862 [2]. It results from the failure of the ventral anlage of the pancreas to rotate with the duodenum during gestation. Symptomatic anemia and a dilated CBD are extremely rare presentations of annular pancreas [3,4]. The diagnosis of this condition can be confirmed by EUS, CT, or MRI [5].