A Histopathological Study of Mean Eosinophil Count in Adult Gastrointestinal Pathologies: A Cross-sectional Study

Introduction: Elevated eosinophil counts are associated with various Gastrointestinal Tract (GIT) conditions, including autoimmune gastritis, gastroesophageal reflux disease, drug reactions, infections, radiation enteritis, collagen vascular disease, and inflammatory bowel disease. Assessing these eosinophils is essential for interpreting endoscopic biopsies, as they are frequently found alongside varying quantities of neutrophils and lymphocytes. Despite the growing prevalence of eosinophil-associated diseases, there is limited information regarding abnormal increases, distribution patterns across different diagnosis, and normal eosinophil levels. Aim: To determine the eosinophil count and its distribution in various gastrointestinal lesions and to examine their association with final diagnosis. Materials and Methods: A cross-sectional observational study was conducted in the Department of Pathology, Ramaiah Medical College, Bengaluru, India on a total of 503 biopsy samples from various sites of the GIT from 299 cases over a period of three months from January 2023 to March 2023. Haematoxylin and eosin-stained slides obtained from formalin-fixed paraffin-embedded blocks of all study patients were reviewed. Eosinophil counts were performed on performed on Haematoxylin and Eosin (H&E) stained slides. Areas with maximal eosinophilic counts were visually identified, and the mean mucosal eosinophilic count was obtained from five different hotspot high-power fields. The average eosinophil count from these five fields was recorded, and the final report was expressed as ‘eosinophils/hpf.’ The average mean eosinophil count was tabulated, and the distribution in various gastrointestinal lesions and their association with the final diagnosis were studied. Statistical Package for Social Sciences (SPSS) version 22.0 software was used for data analysis after the data was entered into a Microsoft Excel spreadsheet. Results: A total of 503 biopsy samples from various sites of the GIT from 299 cases were examined. Higher average mean eosinophil counts appeared to be significantly associated with adenomatous polyps of the stomach (p-value<0.001), transverse colon (p-value=0.001), descending colon and rectum (p-value=0.027), and tuberculosis of the terminal ileum (p-value=0.013). Conclusion: The present study sheds light on the distribution and diagnostic significance of eosinophilic infiltration across various segments of the GIT in present population group. While eosinophils are usually detected in varying numbers in most mucosal biopsies of the GIT, present findings significantly contribute to defining the limits of eosinophil association in different conditions that can feature significant eosinophilia. Highlighting the causes of significant mucosal eosinophilia will also be of profound assistance in considering the differential diagnosis of eosinophilic gastroenteritis.