An adult case of large defect of small mesenteric hiatal hernia causing small bowel obstruction.

Background: Small mesenteric hiatal hernias (SMHHs) are defined as a small group of internal hernias (IHs) that frequently diagnosed in children. However, SMHHs are relatively rare in adults. Bowel loop herniation via an abnormal mesenteric defect can lead to strangulated intestinal obstruction. Congenital SMHHs are commonly observed in pediatric patients, with some cases involving neonatal death.

Case presentation: A 24-year-old healthy male patient visited our hospital with a 2-day history of a sudden onset lower abdominal pain. He was initially diagnosed with enteritis. However, his symptoms worsened, and he was brought to our hospital. Contrast-enhanced computed tomography (CT) scan showed formation of a closed loop in the small intestine within the pelvis and signs of ischemia. As the patient was diagnosed with small bowel obstruction (SBO) caused by IH, emergency laparoscopic surgery was performed to loosen the obstruction. The patient was found to have ascites and small-bowel necrosis. A part of the small intestine that measured 30 cm was strangulated via a large-diameter defect (17 × 11 cm) in the ileal mesentery. Via a small abdominal incision, the necrotic bowel was resected, and the mesenteric defect was repaired.

Conclusion: SMHHs are rare in adults, and they should be considered as potential causes of strangulated intestinal obstruction in adults without a history of laparotomy or trauma.