Ileal duplication cyst linked to type 3A ileal atresia: a rare case report and review of the literature.

BACKGROUND: Jejuno-ileal atresias represent a significant cause of neonatal intestinal obstruction, occurring in approximately 1 in 3000-5000 live births. Terminal ileal atresia, classified as type 3A according to the Louw and Barnard system, specifically involves a mesenteric defect. Ileal duplication cysts, typically cystic or tubular structures sharing a common muscular wall and blood supply with the native ileum, can be communicating or non-communicating and pose risks of obstruction, volvulus, bleeding, or perforation. This case highlights terminal ileal atresia (type 3A) concurrent with an ileal duplication cyst. CASE PRESENTATION: A term male neonate (2900 g), born via a normal delivery, presented on day 3 with low intestinal obstruction: failure to pass meconium, abdominal distension, bilious aspirates, and air-fluid levels on X-ray. Laparotomy on day 5 confirmed type 3A atresia with a 4 × 4 cm communicating duplication cyst that shared a wall and blood supply with the terminal ileum, 12 cm proximal to the ileocecal valve; 15-cm dilated proximal bowel was resected, the cyst was excised, the distal segment was flushed, and a primary anastomosis was performed. DISCUSSION: Antenatal mesenteric vascular accidents likely explain this co-occurrence, causing differential healing in which the spared segments form duplications. Mechanisms include volvulus or intussusception induced by the cyst. CONCLUSION: This case underscores antenatal mesenteric vascular accidents as a likely etiology of concurrent ileal atresia and duplication cysts, supported by histopathological evidence and prior theories. Surgical resection with anastomosis remains effective for such non-separable cysts. Early diagnosis and intervention optimize neonatal outcomes in such uncommon associations in resource-limited settings.