Note that Intestinal Intussusception is a major cause of small bowel obstruction in children (much less common in adults). The leading edge of an intussusception (usually a pedunculated polypoid tumor) can be demonstrated in 80% of adults. In children, there is infrequently any apparent anatomic etiology.
Intussusception. Coiled-spring appearance (arrow) in jejuno-jejunal intussusception.