Do Routine Gastric and Duodenal Biopsies Add Value in Patients with Eosinophilic Esophagitis? Evidence from a Large Single-Center Case Registry

Background/Objectives: The recommendation of routine gastric and duodenal biopsies at index endoscopy on suspicion of eosinophilic esophagitis (EoE) remains controversial because of the limited supporting evidence. We aimed to evaluate the prevalence, clinical relevance, and predictors of gastric and duodenal histopathology in a large real-world EoE cohort. Methods: This retrospective single-center study included adult and pediatric patients with EoE diagnosed between 2001 and 2024 and enrolled in the EoE CONNECT registry. Gastric and/or duodenal biopsies obtained at diagnosis or follow-up were reviewed. Histologic findings were classified into specific diagnostic categories and analyzed according to clinical presentation, endoscopic features, and age group. Results: We evaluated 340 patients (35.7% children), of whom 88.5% underwent both gastric and duodenal biopsies. The overall diagnostic yield for extra-esophageal findings was 20.9%, predominantly Helicobacter pylori-associated gastritis (18.8%), but with a very low yield of clinically meaningful diagnoses such as celiac disease (0.6%) and eosinophilic gastritis (0.3%). Symptoms and endoscopic abnormalities were not significantly associated with pathological findings (p=0.11). Moreover, age-stratified analysis revealed no significant differences in specific diagnoses, although patients with pathological extra-esophageal biopsies were significantly older (p<0.001). Follow-up biopsies demonstrated resolution of most pathological findings after the initial diagnosis, with Helicobacter pylori-associated gastritis accounting for the majority of cases that resolved. Conclusions: Routine extra-esophageal biopsies in the context of patients with EoE have a low diagnostic yield and rarely alter clinical management, regardless of age. Therefore, our findings advocate for a selective rather than universal approach to extra-esophageal sampling in patients with EoE.