Pathomorphological features of eosinophilic esophagitis before and after treatment with proton pomp inhibitors

Eosinophilic esophagitis (EoE) is characterized by predominant eosinophilic infiltration of esophageal mucosa, >15 eosinophils in a high power field (HPF). Proton pomp inhibitors (PPI) are medications of choice to start therapy of EoE. Objective. To perform histological and morphometric analysis of biopsy pieces of esophageal mucosa before and after treatment with PPI. Material and methods. Of the 84 patients newly diagnosed with EoE, 30 were in the PPI therapy group. Patients underwent esophagogastroduodenoscopy with biopsy for initial diagnosis and follow-up evaluation. Biopsy specimens were stained with hematoxylin and eosin, combined PAS/Alcian blue staining and Mallory staining to detect fibrosis. Morphometric analysis was performed using the Eosinophilic Esophagitis Histologic Scoring System (EoEHSS) for initial diagnosis and Eosinophilic Esophagitis Histology Remission Score (EoEHRS) to assess the onset of remission. Results. In initial biopsies peak eosinophil count comprised 46 (25—89) eosinophils HPF, rates of basal zone hyperplasia and dilated intercellular spaces were both 100%, followed by lamina propria fibrosis (98.04%), surface epithelial alteration (77.38%), eosinophilic abscesses (57.14%), eosinophil surface layering (28.57%) and dyskeratosis (21.43%). Using EoEHSS, the total score for the grade was 12 (8—13.75) and the total score for the stage was 10 (8—12). Peak eosinophil count after the treatment alleviated in all the patients (4 (1—12) eosinophils HPF, p<0.05). The severity and the extent of other parameters has significantly decreased. Using EoEHSS, the total score for the grade was 4 [3—8] and the total score for the stage was 4 (3—7), p<0.05. Conclusion. Not only peak eosinophil count, but structural changes of esophageal mucosa should be taken into account while evaluating biopsies for initial diagnostic and to analyze the treatment response. EoEHRS remission criteria were reached in 40% patients on PPI therapy.