See “Good Agreement Between Endoscopic Findings and Biopsy Reports Supports Limited Tissue Sampling During Pediatric Colonoscopy” by Manfredi et al on page 773.
In contrast to the practice in adult gastroenterology, obtaining biopsies at the time of an endoscopic procedure has been considered important for the endoscopic evaluation of infants and children. Manfredi et al (1) question this practice in children having a colonoscopy by demonstrating a good correlation between endoscopic and histologic findings. In children with a normal-appearing mucosa, the likelihood of having a normal colonic biopsy is extremely high. Most of the discrepancy between visual and histologic findings occurred when the mucosa appeared to be abnormal, but the pathologist found normal histology. Patients who were immunosuppressed or who had or were suspected of having inflammatory bowel disease were more likely to be in the group with abnormal histology and normal-appearing mucosa.
Earlier studies from our group identified intraepithelial eosinophils in the upper gastrointestinal tract in the esophagus of children with symptoms of reflux as an early marker of inflammation (2). Had mucosal biopsies not been obtained from normal-appearing mucosa, this biomarker would not have been identified.
This recent study raises the issue as to the relevance of colonic mucosal biopsies in children with a normal-appearing mucosa. Because approximately 90% of the subjects in this retrospective, but consecutively enrolled cohort were >20 kg, the observations apply primarily to children >5 years of age. Clinicians should be careful in extrapolating these data to younger children who may be more likely to have mucosal inflammation related to dietary protein intolerance without appreciable endoscopic changes. Mucosal biopsies in young children may also identify a lack of B cells or changes in T-cell subsets that support a diagnosis of an immunoregulatory defect. These conditions are often suspected based on a clinical history of recurrent infections or specific laboratory studies and represent a group in which mucosal biopsies may be diagnostic. For these reasons, additional data in children <5 years of age are needed to determine the relevance of biopsies in this age group.
As Manfredi et al point out, colonoscopy is often performed in older children to diagnose inflammatory bowel disease. If the endoscopy appears normal, the likelihood of finding pathology on histology is low. Rare conditions such as microcytic colitis, including lymphocytic and collagenous colitis, can only be diagnosed by mucosal biopsy. Furthermore, patients with Crohn disease may have mucosal granulomata in biopsies with normal-appearing mucosa. Although this report raises important questions about the value of mucosal biopsies in a cost-containing environment, future studies should be powered to determine which patients are most likely to benefit from biopsies. Perhaps the strategy mentioned by the authors of reducing the number of biopsies using “endoscopic appearance and evidence-based risk stratification” will enable clinicians to have the confidence they need to reassure their patients that the colonic mucosa is indeed normal. Perhaps the location of the biopsy is not relevant if there is a specific finding such as a granuloma or absent B cells. Prospective studies that are appropriately powered may guide us in deciding how many biopsies should be obtained from a normal-appearing area of the colon. Until this evidence exists, clinicians will (and should) continue to take biopsies from normal-appearing areas, although based on Manfredi et al's study, they may elect to take fewer biopsies collected into a smaller number of specimen containers.
1. Manfredi MA, Jiang H, Borges LF, et al. Good agreement between endoscopic findings and biopsy reports supports limited tissue sampling during pediatric colonoscopy. J Pediatr Gastroenterol Nutr
2. Winter HS, Madara JL, Stafford RJ, et al. Intraepithelial eosinophils: a new diagnostic criterion for reflux esophagitis. Gastroenterology