Adenocarcinoma of the sigmoid colon causing sigmoido-rectal intussusception: A rare entity in adults

Introduction: Intussusception occurs when a more proximal portion of the bowel (intussusceptum) invaginates into the more distal bowel (intussuscipiens). The pathomechanism is thought to involve altered bowel peristalsis at the intraluminal lesion, which is then a lead point for the intussusceptum. Intestinal intussusception is rare in adults, accounting for approximately 1 % of all bowel obstructions. We report a unique case in which a partially obstructing sigmoid cancer caused full thickness rectal prolapse requiring surgical intervention. Presentation of case: A 75-year-old male presented in the emergency department due to anal haemorrhage for 5 days. On clinical examination his abdomen was distended with signs of peritoneal irritation in the right quadrants. The CT scan showed sigmoid-rectal intussusception with an sigmoid colonic tumour. The patient underwent emergency anterior resection of the rectum without reduction of the intussusception. Histological examination revealed a sigmoid adenocarcinoma. Discussion: Intussusception is the most common urgent situation among the pediatric population but its incidence in adults is very rare. The diagnosis is difficult to establish with history and physical exam findings alone. Since in adults, unlike children, in most cases a malignant pathology acts as a lead point, the treatment of this pathology still reserves doubts. Recognizing and understanding pertinent signs, symptoms, and imaging findings is essential to the early diagnosis and appropriate management of adult intussusception. Conclusion: The appropriate management of adult intussusception is not always clear cut. There is controversy about the reduction before resection in cases of sigmoidorectal intussusception.