Symptomatic Annular Pancreas in an Elderly Adult Diagnosed by EUS and Secretin MRCP

Abstract

Purpose: Annular pancreas (AP) is a rare congenital abnormality in which the ventral portion of the pancreas fails to rotate with the duodenum during embryological development, thus causing the ventral portion to remain partially or fully enveloped around the duodenum. The incidence of AP is unknown, as many cases are asymptomatic and undiagnosed. Adults with AP may present with a variety of symptoms suggestive of gastric outlet obstruction, or may present with gastrointestinal bleeding, pancreatitis, or biliary obstruction. Although as many as 50% of patients present in adulthood, there have been no published reports of cases above the age of 76. Surgery continues to remain the diagnostic “gold standard” for AP, but imaging techniques such as computed tomography (CT), magnetic resonance imaging, endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS) can now be used to make the diagnosis. We report the case of an 85 year old gentleman who presents with symptoms of partial gastric outlet obstruction who was diagnosed with AP by EUS and secretin magnetic resonance cholangiopancreatography (MRCP). Methods: N/A Results: An 85 year old gentleman with a past medical history of hypertension, diabetes, and cerebrovascular disease was admitted to the hospital for the evaluation of intermittent abdominal pain, nausea, vomiting, and weight loss. CT of the abdomen revealed a soft tissue mass surrounding the second portion of the duodenum causing duodenal compression. Esophagogastroduodenoscopy revealed a narrowed duodenal lumen as well as the presence of a duodenal diverticulum. EUS was performed revealing the soft tissue mass to be pancreatic tissue of normal echogenicity with the presence of an annular duct confirming the diagnosis of AP. ERCP was unable to be performed as the major papilla was within the duodenal diverticulum and could not be cannulated. Dynamic MRCP, with the intravenous administration of secretin, was performed to evaluate both the pancreatic and biliary ducts revealing no ductal dilatation but again confirming the diagnosis of AP. Conclusion: AP is a rare presentation in the elderly, yet a high index of suspicion needs to be maintained in elderly patients with a presentation of gastric and duodenal outlet obstruction. We highlight the role of EUS and secretin MRCP as highly sensitive and safe modalities compared to standard ERCP, with its associated risk of pancreatitis, to diagnose AP and its associated ductal abnormalities.