Clinical Characteristics of Chronic Rhinosinusitis With Nasal Polyp According to Histopathological Endotypes and Staining Method for Neutrophilic Polyp Classification and Its Clinical Implication

Abstract

Background and Objectives There are various methods used to histologically assess the cell count of neutrophils in nasal polyps. With various classification of neutrophilic nasal polyps, determining the appropriate staining techniques and criteria is deemed important for the diagnosis of neutrophilic nasal polyps by assessing neutrophil cell counts. In this study, we tried to optimize different methods of neutrophil counting and staining by comparing clinical outcomes.Subjects and Method We studied 207 patients who underwent endoscopic sinus surgery for chronic rhinosinusitis with nasal polyp from August 2014 to September 2018. Patients’ nasal polyp were taken to make following three slide sections: hematoxylin and eosin, human neutrophil elastase (HNE), myeloperoxidase. After staining, microscope picture (×400) was taken and neutrophils were counted. Neutrophil polyp (NP) was classified either by the tissue neutrophil count (20/HPF) or by the neutrophil percentage (1%/total cell) for clinical outcome comparison.Results Two groups were made after HNE staining: the NP and the non-NP groups. The L-K scores and delta showed significant differences between each group while neutrophil was defined based on 20 counts/HPF (<i>p</i><0.001). By Kaplan-Meier estimation, there was no statistical meaning between the two groups. But the NP group had a tendency to recur more than the non-NP group while 20 counts/HPF definition was used (<i>p</i>>0.05).Conclusion HNE staining and 20 counts/HPF were the most specific for neutrophil counting. Analyzing the nasal polyp into two groups due to histologic types showed that the NP group had worse prognosis than the non-NP group. In conclusion, neutrophils in the nasal polyp might be considered seriously for clinical outcomes.