The incidence of pediatric inflammatory bowel disease is increasing worldwide, with a corresponding increase in the demand for colonoscopy. Colonoscopy is an invasive procedure and can be challenging in children. Additionally, colon cancer is rare in children; therefore, colonoscopy is usually not necessary. Careful history-taking and physical examination can accurately distinguish between several diseases, thereby obviating the need for colonoscopy to establish the diagnosis in children. A child’s age is an important factor in narrowing the differential diagnosis. Nevertheless, if diagnoses are not clinically distinguishable, endoscopy is necessary. The European Society for Paediatric Gastroenterology Hepatology and Nutrition guidelines published in 2017 provide indications for colonoscopy in children with unexplained anemia and/ or diarrhea, perianal lesions, rectal bleeding, and unexplained growth retardation [1].

Although some cases of lower gastrointestinal bleeding can be diagnosed clinically [2], diagnosis is challenging in children with lower gastrointestinal bleeding without other symptoms. Silbermintz et al. [3] described the role of endoscopic examination for diagnosis in children with lower gastrointestinal bleeding without other symptoms. The most common cause of asymptomatic lower gastrointestinal bleeding in children is juvenile polyps [2,4]; therefore, suspected juvenile polyps in children serve as an indication for colonoscopy. Several previous studies have reported that polyps were found in 7%–27.2% of children undergoing colonoscopy [4-7]. A multicenter study investigating 13,115 children who underwent colonoscopy in the USA reported that polyps were detected in 6.1% of all children who underwent colonoscopy and in 12% of children with lower gastrointestinal bleeding [5]. A study by Silbermintz et al. [3] excluded children with clinically suspected inflammatory bowel disease, those with previously diagnosed polyps, and those with familial adenomatous polyposis. Therefore, it is not possible to directly compare the prevalence of colon polyps with that reported in other studies. Nevertheless, Silbermintz et al. [3] reported that 41.6% of children who underwent colonoscopy for lower gastrointestinal bleeding without other symptoms were diagnosed with colonic polyps. This indicates that although colonoscopy is challenging in children, this examination is needed because of the relatively high incidence of polyps in children with lower gastrointestinal bleeding without other symptoms. It is important to note that polyps can readily be diagnosed and treated with colonoscopy.

Solitary polyps found in children are known to occur most commonly in the left-sided colon. Silbermintz et al. [3] reported that left-sided colon polyps were detected in 94.2% of children; however, children with polyposis syndrome or familial adenomatous polyposis were excluded from the study. Therefore, the prevalence of left-sided colon polyps in this study was higher than that observed in other studies. Our previous report demonstrated 84.9% of polyp located in left-sided colon [8]. A study that investigated 45% of children with multiple colon polyps reported that 35% of all polyps were found proximal to the sigmoid colon [9]. Another study performed in Taiwan reported that only 43.6% of juvenile polyps occurred in the rectosigmoid colon, and a solitary polyp was reported in 92.3% of cases [10]. Clinicians need to be aware that polyps may occur in the proximal colon and that multiple polyps or polyposis may occur anywhere in the colon; therefore, the initial colonoscopy should include a thorough examination of the entire colon.

In conclusion, colonoscopy is a useful test in children with suspected colonic lesions. The incidence of colonic polyps is relatively high in children with lower gastrointestinal bleeding without other symptoms. Colonoscopy is a useful diagnostic and therapeutic modality in children with colonic polyps. It should be performed in children only when absolutely necessary. Although most colonic polyps tend to occur in the left-sided colon, examination of the entire colon is recommended for accurate diagnosis.