A Rare Cause of Pediatric Small Bowel Obstruction: Congenital Rectouterine Hernia.

Small bowel obstruction caused by herniation through a peritoneal defect in the rectouterine pouch is an exceptionally rare entity, particularly in pediatric patients. We report the case of a 17-year-old previously healthy, nulliparous female who presented with four days of nausea, vomiting, and diffuse abdominal pain. She reported prior self-resolving episodes of similar symptoms, raising the possibility of intermittent herniation. CT demonstrated a high-grade small bowel obstruction with dilated loops in the pelvis and ascitic fluid, though specific signs of internal hernia, such as the mesenteric swirl sign or closed-loop configuration, were absent. Following a failed Gastrografin challenge, diagnostic laparoscopy was performed. Intraoperatively, a segment of small bowel was found incarcerated within a peritoneal defect in the rectouterine pouch. The bowel was successfully reduced laparoscopically and appeared viable. The hernia sac was excised, and the defect was widened to eliminate the potential space and prevent recurrence. The patient recovered uneventfully, with return of bowel function on postoperative day 1 and discharge on postoperative day 2. Pathologic examination confirmed fibroadipose tissue with reactive mesothelial lining consistent with a hernia sac. Given the patient's young age, nulliparity, and absence of prior pelvic surgery, a congenital etiology is favored, though this remains presumptive. Rectouterine pouch hernias are difficult to diagnose preoperatively because their presentation is nonspecific and imaging findings are often subtle, although a pelvic transition point may provide a clue. Definitive diagnosis is typically made intraoperatively. Prompt surgical intervention is essential to prevent bowel ischemia or strangulation, and laparoscopy provides both diagnostic and therapeutic benefit. To our knowledge, this represents the second reported pediatric case of a rectouterine pouch hernia and highlights the importance of considering rare internal hernias in adolescents presenting with bowel obstruction. Early minimally invasive exploration can facilitate timely diagnosis and effective management while minimizing morbidity.