We present the case of a 12-year-old girl with Peutz-Jeghers syndrome (PJS). Enormous polyps of the transverse colon intussuscepting into the rectum turned out to be the rate cause of overflow incontinence. Although she presented all the signs of PJS at infancy, diagnosis was made only after a period of nine years, implying a lack of follow-up. We emphasize that when polyps occur in children, a complete examination is required, and once the diagnosis of Peutz-Jeghers syndrome is established, frequent endoscopic follow-up and resection of polyps are necessary.