Annular Pancreas in a 13-Year-Old Boy: A Delayed Clinical Presentation of a Congenital Anomaly Highlighting Challenges of Diagnosis.

Introduction: The annular pancreas is a rare congenital anomaly that typically results in duodenal obstruction during the neonatal period. However, its presentation can be variable, with some cases remaining undiagnosed until adolescence and posing diagnostic challenges, especially in low-resource settings where advanced imaging may be limited. Case Presentation: We report the case of a 13-year-old boy with a three-year history of recurrent non-bilious projectile vomiting and epigastric pain. Despite normal laboratory findings, plain computed tomography (CT) and post-intravenous (IV) contrast CT scans revealed features suggestive of gastric outlet obstruction, including significant stomach distention and abrupt tapering of the duodenum. Owing to the inconclusive imaging results, surgical exploration was pursued. Intraoperative findings confirmed the presence of a band of pancreatic tissue encircling the first part of the duodenum, thereby establishing the diagnosis of an annular pancreas. A gastroduodenostomy was successfully performed, resulting in an uneventful recovery and resolution of symptoms during subsequent follow-up. Conclusion: This case underscores the importance of maintaining a high index of suspicion for the annular pancreas in patients presenting with chronic gastrointestinal symptoms. Although imaging modalities provide valuable clues, surgical exploration remains the gold standard for achieving a definitive diagnosis when findings are ambiguous. The successful surgical management of this patient underscores the crucial role of timely intervention, particularly in settings with limited diagnostic resources.