Does the severity of tissue eosinophilia of colonic neoplasms reflect their malignancy potential?

BACKGROUND/AIMS It was speculated that there was a relationship between the intensity of tissue eosinophilic infiltration in colonic malignancies and their prognosis. This retrospective study aimed to investigate the frequency and intensity of tissue eosinophilia in various colonic neoplasms, including serrated adenomas. METHODS We evaluated 448 colonic neoplasms to determine eosinophilic infiltration: 96 hyperplastic polyps, 50 serrated adenomas, 19 flat adenomas, 154 tubular adenomas, 71 tubulovillous adenomas, 13 villous adenomas and 45 adenocarcinomas. The eosinophilic infiltration was categorized into three groups by evaluating the percentage of eosinophils relative to total stromal inflammatory cells: mild (0-5%), moderate (5-40%), and marked (>;40%). Chi-square and Fisher's exact tests were used for analyses. P value <0.05 was considered statistically significant. RESULTS Moderate (46.7%) and marked (52.9%) intensity were noted in all colonic adenomas. Most of the hyperplastic polyps (96%) and adenocarcinomas (75.6%) showed mild intensity. Mostly moderate eosinophilic infiltration was observed in serrated adenomas. CONCLUSIONS Our findings suggest that the intensity of tissue eosinophilia is most prominent in adenomas including serrated adenomas and is diminished from adenoma to carcinoma. This finding may be used as a diagnostic indicator.