Inverted appendix mistaken for a polyp during colonoscopy and leading to intussusception.

A spectrum of appendiceal diseases, ranging from simple mucous distension to acute perforated appendicitis, are seen in patients with CF. We report a 6 year old boy with CF and recurrent periumbilical pain. During colonoscopy, a fleshy pedunculated mass at the junction of the ascending colon and caecum was mistaken for a polyp and excised.