Structured histopathology and laboratory evidence in nasal polyposis with different pathogenesis.

Purpose: Non-steroidal anti-inflammatory drugs-exacerbated respiratory disease (NERD), intrinsic asthma, eosinophilic granulomatosis with polyangiitis (EGPA) and odontogenic sinusitis may be associated with nasal polyps. The aim of the study was to compare circulating inflammatory cells and structural histopathology of these groups of nasal polyposis. Methods: We retrospectively evaluated 71 patients with nasal polyps stratified according to the above-mentioned pathogenesis. All patients underwent preoperative laboratory investigations and primary endoscopic sinus surgery. Surgical specimens were submitted to structured histopathological evaluation. Results: The median tissue eosinophil count (cells/HPF) was significantly different between the considered groups of nasal polyposis (p=0.0004). The median of NERD sub-cohort was significantly higher than intrinsic asthma (p=0.0030), odontogenic CRS (p=0.0001) and EGPA ones (p=0.0094). Eosinophilic aggregates positive rate was significantly higher in NERD sub-cohort than in odontogenic CRS (p=0.0072), EGPA (p=0.0497) and asthma (p=0.0188) ones. EGPA sub-cohort had a higher neutrophil infiltrate positive rate than NERD (p=0.0105) and intrinsic asthma ones (p=0.0040). Odontogenic CRS sub-cohort had a higher neutrophil infiltrate positive rate than NERD (p=0.0140) and asthma ones (p=0.0096). EGPA sub-cohort had a higher presence of fibrosis than NERD (p=0.0237) and odontogenic CRS sub-cohort (p=0.0107). Odontogenic sub-cohort had a lower subepithelial edema positive rate than NERD (p=0.0028) and asthma (p=0.0149) ones. Conclusions: Structural histopathology may identify nasal polyps histotypes with different morphological patterns. The identified histopathological features can facilitate the recognition of rational therapeutic and followup approaches that consider the tissue modifications associated with the response to drugs and surgery.