Colonoscopy diagnosis of recurrent abdominal pain in a 4-year-old boy with intestinal duplication cyst involving colon, appendix, and ileum: a case report.

Background: Intestinal duplication cyst is an infrequent congenital malformation that can involve all the segments of the gastrointestinal tract. The cases of intestinal duplication cyst involving the colon, appendix, and ileum in children are particularly uncommon. The symptoms of abdominal pain are similar to other acute abdominal diseases in children, such as appendicitis, intussusception, and intestinal obstruction, so sometimes its diagnosis is challenging and leads to misdiagnosis.

Case presentation: We report a 4-year-old Asian boy who presented to the pediatric emergency department with abdominal pain and vomiting but no fever, peritonitis, or mass. No abdominal abnormality was found via radiology and ultrasonography. After 2 days' anti-inflammatory therapy, the patient was discharged with pain relief. A total of 9 months later, he was readmitted to the pediatric emergency department for the same complaint as the first admission. Abdominal physical examination and ultrasound examination were still negative. Barium examination found a large mass in the colon. Colonoscopy was performed before operation to confirm the rare co-cavity intestinal duplication cyst involving the colon, appendix, and ileum. After resection of intestinal duplication and ileocolonic anastomosis, the patient's abdominal pain and vomiting has not recurred for 5 years postoperatively.

Conclusions: The diagnosis of intestinal duplication cyst in children is difficult, especially the rare co-cavity and long segmental intestinal duplication, which is easily misdiagnosed. Colonoscopy may be an effective auxiliary diagnostic method, especially for diseases that are difficult to diagnosed clinically, such as recurrent abdominal pain.