Internal herniation secondary to congenital mesenteric defect with associated fibrous congenital bands in an adult male

Internal hernias secondary to congenital mesenteric defects are a rare cause of small bowel obstruction (SBO) in adults. Additionally, the identification of chronic congenital mesenteric defects and congenital bands is notably rare. Herein, we report the case of an 18-year-old man presenting with acute abdominal pain and bilious vomiting, without constipation or distention. Contrast enhanced computed tomography demonstrated dilated small bowel loops consistent with obstruction. Emergency laparoscopy revealed internal herniation of the small bowel through a congenital mesenteric defect, along with two fibrous congenital bands. The procedure was converted to laparotomy, during which the bands were divided, the hernia was reduced, and the mesenteric defect was closed. The patient recovered uneventfully. This case highlights the diagnostic challenges of congenital internal hernias causing SBO in adults and reinforces the importance of maintaining awareness of this rare entity in the evaluation of SBO in the virgin abdomen.