Cystic duplication of the caecum mimicking intussusception.

Diagnosis of gut duplications are often only made intraoperatively as they are uncommon and do not feature strongly in the differential diagnoses. A case of caecal cystic duplication mimicking intussusception is discussed with the aim of improving diagnostic accuracy in future cases. A 7 month old boy presented with the classical triad of abdominal pain, bleeding per rectum and a palpable mass. Barium enema revealed a mass in the caecum suggestive of an intussusceptum. Repeated attempts at hydrostatic reduction were unsuccessful as the mass was immobile. Laparotomy revealed cystic duplication of the caecum without intussusception. The bleeding per rectum was due to an ulcer in the colonic epithelium overlying the cyst.