Intersigmoid Hernia Masquerading as Small Bowel Stricture: A Diagnostic Challenge.

Internal hernias are an exceptionally uncommon cause of small bowel obstruction. Among these, sigmoid-mesocolon hernias, particularly intersigmoid hernias, are one of the rarest subtypes. A 66-year-old male with no history of abdominal or groin surgery presented with a six-hour history of acute lower abdominal pain and 48 hours of absolute constipation. Computed tomography demonstrated dilated small bowel loops with a transition point in the left iliac fossa. Initial conservative management failed to relieve symptoms. Midline laparotomy revealed a viable loop of mid-ileum herniated into a peritoneal pouch adjacent to the sigmoid colon, consistent with an intersigmoid internal hernia. The bowel was reduced, and the peritoneal recess was obliterated. The postoperative course was uneventful, and the patient was discharged home on day four. Intersigmoid internal hernia is an exceedingly rare cause of small bowel obstruction and should be considered in patients without prior abdominal surgery. Early surgical intervention remains key to preventing strangulation and ensuring favourable outcomes.