Gastric intestinal metaplasia in children and adolescents is reversible upon reaching adulthood

Background/Objectives: Gastric intestinal metaplasia (GIM) is considered an irreversible preneoplastic precursor for gastric adenocarcinoma in adults. However, its significance in children and the long-term outcome remain poorly understood. Methods: All children diagnosed with GIM between 2000 and 2020 were identified at a large tertiary referral centre. Upon reaching adulthood (≥18 years), the patients were invited to undergo follow-up esophagogastroduodenoscopy (using narrow-band imaging additionally to high-definition white light endoscopy), with gastric biopsies obtained according to the updated Sydney protocol. Childhood and adulthood gastric biopsies were re-evaluated by two experienced gastrointestinal pathologists using Kreyberg staining. Results: Paediatric GIM was diagnosed in 178/14,409 (1.2%) esophagogastroduodenoscopies performed during the study period. Fifty adult patients with childhood GIM agreed to participate in the study. The mean age at childhood and adulthood endoscopies were 14.3 years (median 15) and 25.2 years (median 24), respectively. The mean follow-up interval was 10.5 years. All childhood GIM cases were classified as complete-type. Notably, GIM completely resolved in 41/50 of patients (82%) by the time of adulthood follow-up. No dysplasia or carcinoma was detected in any patient. Childhood Helicobacter pylori infection, similar to other evaluated host-related factors, was not significantly associated with the persistence of GIM into adulthood (11.2% vs. 29.3%, p = 0.41). Conclusions: Childhood GIM was a rare finding but demonstrated a high rate of reversibility by adulthood regardless of Helicobacter pylori status, with no cases of dysplasia or carcinoma observed during long-term follow-up.