Annular Pancreas Causing Gastric Diverticulum in a 29-Year-Old Man: A Rare Complication of an Uncommon Condition

CASE REPORT Annular pancreas (AP) is a rare congenital anomaly characterized by pancreatic tissue encircling the duodenum, leading to variable degrees of obstruction.1,2 In adults, AP is often misdiagnosed because of its nonspecific presentation.3 Chronic duodenal obstruction may result in complications, including gastric diverticulum.4 A 29-year-old man presented with a 5-year history of recurrent postprandial abdominal pain, early satiety, and nonbilious vomiting. He reported progressive weight loss over the previous year. Prior evaluations, including a noncontrast computed tomography in his home country (Haiti), were unremarkable. A repeat evaluation in the United States revealed persistent gastric distention. Upper endoscopy revealed retained food and a prepyloric diverticulum (Figure 1). A 5.8-mm ultra-slim endoscope failed to pass through the pylorus. Contrast-enhanced computed tomography and magnetic resonance imaging demonstrated a complete AP encircling the second portion of the duodenum with upstream gastric dilation (Figures 2 and 3). The patient underwent laparoscopic gastrojejunostomy, which confirmed duodenal obstruction due to AP. Given the limited space, a hand-sewn gastrojejunostomy was performed. Postoperatively, the patient recovered well, tolerating a full oral diet. Follow-up showed complete symptom resolution.Figure 1.: Upper endoscopy showing prepyloric diverticulum of stomach (yellow arrow) and pylorus (box).Figure 2.: Contrast-enhanced axial abdominal computed tomography scan highly suggestive of annular pancreas configuration (arrows), encircling the second portion of the duodenum (arrowhead), and a distended stomach (curved arrow).Figure 3.: Axial T1 magnetic resonance imaging depicting a complete annular pancreas (arrows) around the proximal second portion of the duodenum(arrowhead), with an enlarged stomach (curved arrow).This case highlights AP as a rare but important consideration in adults with unexplained gastric outlet obstruction and the potential for secondary gastric diverticulum formation. DISCLOSURES Author contributions: S. Boateng: Conceptualization, manuscript drafting, literature review, final approval and is the article guarantor. G. Heymann: Critical revision, imaging interpretation, final manuscript approval. F. Mejia: Case review, manuscript editing, final approval. BA Lerner: Surgical insights, manuscript review, final approval. C. Loeser: Supervision, manuscript review, final approval. Financial disclosure: None to report. Informed consent was obtained for this case report.