S3209 Annular Pancreas as a Cause of Recurrent Pancreatitis and Exocrine Insufficiency: A Case Report

Introduction: Annular pancreas, an uncommon congenital anomaly, involves pancreatic tissue encircling the duodenum's second part, with a prevalence estimated at 3-15 cases per 100,000 individuals in various populations. Often asymptomatic and found incidentally in adults, it can manifest with abdominal pain, post-prandial fullness, nausea, or vomiting. This clinical case report aims to explain how annular pancreas can present through recurrent acute pancreatitis episodes, potentially fostering progression to chronic pancreatitis and its associated complications, notably exocrine pancreatic insufficiency. Case Description/Methods: A 51-year-old man, with a history of cholecystectomy for a gallbladder polyp, presented with several years of intermittent right upper quadrant abdominal pain. During these episodes, serum amylase and lipase levels were consistently elevated. Contrast-enhanced computed tomography scans during these episodes did not show typical definitive signs of acute pancreatitis. Further investigation with magnetic resonance imaging revealed an annular pancreas at the level of the pancreatic head, causing relative narrowing of the second duodenal segment over approximately 3 cm. The pancreatic duct followed a looped course at this particular level, but the common bile duct and main pancreatic duct were otherwise normal. Laboratory tests showed mildly elevated triglycerides and a markedly decreased fecal elastase level, indicative of developing exocrine pancreatic insufficiency. IgG4 levels were normal. Esophagogastroduodenoscopy (EGD) showed a 10 mm subepithelial bulge in the postbulbar duodenum and a broad-based 15 mm subepithelial lesion near the second duodenal portion, adjacent to the annular pancreas identified. Endoscopic ultrasound (EUS) confirmed the annular pancreas and demonstrated a focal, likely benign lesion in the pancreatic head, suggestive of early-stage chronic pancreatitis. Discussion: This case highlights annular pancreas presenting with recurrent episodes of acute pancreatitis and evidence of exocrine pancreatic insufficiency. The diagnosis was established through advanced imaging (magnetic resonance imaging, EUS) after initial computed tomography scans were non-diagnostic for typical pancreatitis. This case underscores the importance of considering annular pancreas in the differential diagnosis of recurrent pancreatitis, especially when initial imaging is inconclusive. Comprehensive evaluation, including assessment for exocrine function, is crucial for appropriate management and improving outcomes.