A88 EARLY-ONSET GASTRIC POLYPS IN CHILDREN WITH FAMILIAL ADENOMATOUS POLYPOSIS: A CASE SERIES

Abstract

Abstract Background Familial adenomatous polyposis (FAP) syndrome is a familial inherited autosomal dominant polyposis syndrome which predisposes affected individuals to a significantly increasing risk of colorectal cancer before the age of 30 years. Studies examining the rates of duodenal and gastric neoplasia in patients with FAP are scarce. Recent reports have shown a concerning rise in gastric cancer in Western FAP patients with certain endoscopic features. Current guidelines suggest screening with gastroscopy beginning at the age of 20 to 25 years. Aims We report a case series of seven pediatric patients with evidence of early-onset upper gastrointestinal adenomatous polyps. Methods A retrospective chart review was performed for all patients diagnosed with FAP between January 2012 and December 2016 in Winnipeg Children’s Hospital which is the only pediatric tertiary-care hospital in Manitoba. A total of seven pediatric patients from 3 different families were enrolled in our case series. The following data were collected: age of diagnosis, gene mutation, time of first screening endoscopy and total number of endoscopies, number of gastric and colonic polyps, pathology results, surgeries and further routine investigations. Descriptive data were then reported on each patient. Results Five of seven patients (71.4%) exhibited maternal inheritance of the APC gene mutation. The mean age of diagnosis was 5.3 years (SE 2.4, range 2–9 years) with male predominance (n=5, 71.4%). Mean age at first colonoscopy was 9.8 years (SE 2.05; range 6.6–11.9) and 9.9 years (SE 1.88; range 6.6–11.9 years) at first gastroscopy. Five (71.4%) patients had evidence of gastric polyps and three (43%) had evidence of duodenal polyps before the age of 14 years. All patients showed an increasing burden of gastric polyposis with age. Tubular adenomas were seen in all patients who developed >50 gastric polyps (n=5), two with low-grade dysplasia diagnosed at the ages of 11 and 15 year. One patient with duodenal polyps showed tubular adenomatous changes at the age of 13.6 years. Capsule endoscopy was performed in all patients and none showed any small bowel polyposis beyond the duodenum. All seven patients had colonic tubular adenomas, two with low-grade dysplasia (at ages of 14 and 15 years) and only one without polyps at the initiation of endoscopic screening. No patients underwent surgery prior to age 15 years. Conclusions The presence of gastric and duodenal polyps in pediatric patients with FAP is not uncommon and may be underestimated. Early screening gastroscopy with gastric and duodenal biopsies should be considered at a younger age than what has currently been recommended. Funding Agencies None