Usefulness of the Eosinophilic Esophagitis Histologic Scoring System in Distinguishing Active Eosinophilic Esophagitis From Remission and Gastroesophageal Reflux Disease

Background: Eosinophilic esophagitis (EoE) is defined as esophageal dysfunction in the presence of > 15 intraepithelial eosinophils per high-power field (eos/hpf) in either the mid or distal esophagus. The current focus of EoE pathologic evaluation is the peak eosinophil count (PEC), although histologic features other than eosinophilic inflammation are also commonly observed. In addition, histologic variance between the mid and distal esophagus in EoE has not been rigorously studied. The aim of our study was to utilize a recently developed EoE histologic scoring system (EoEHSS) to compare the mid and the distal esophageal histology in patients with active EoE (EoE-A), EoE in remission (EoE-R), and gastroesophageal reflux disease (GERD). Methods: EoEHSS was used to prospectively evaluate the severity and extent of changes in multiple histopathologic features (PEC; basal zone hyperplasia (BZH); eosinophilic abscesses (EA); eosinophil surface layering (ESL); dilated intercellular spaces (DIS); surface epithelial alteration (SEA); dyskeratotic epithelial cells (DEC); lamina propria fibrosis (LPF)) in the mid and distal esophageal biopsies in 85 pediatric patients at a tertiary medical center. These patients were divided into three cohorts: EoE-A (n = 36), EoE-R (n = 12) and GERD (n = 37). Results: Total grade (severity) and stage (extent) scores were significantly higher in EoE-A compared to EoE-R and GERD patients in both the mid and the distal esophagus. The mean total grade scores in the mid esophagus, but not the distal esophagus remained higher in EoE-R as compared to GERD patients. Specific histopathologic features independent of PEC were different in distal and mid esophagus in EoE-A. About one-half of children with active EoE had different EoEHSS scores in their mid and distal esophageal biopsies. Conclusions: EoEHSS yields histologic insights beyond those derived from PEC and helps in more objective, reproducible and accurate diagnosis of EoE and GERD. It also provides a more comprehensive understanding into the pathophysiology of EoE.