Histopathological and hematological changes in recurrent nasal polyposis.

Background There is a dearth of information regarding the histological and hematological differences between primary and recurrent chronic rhinosinusitis with nasal polyps (CRSwNP). The present study analyzed the histological changes in recurrent CRSwNP in terms of eosinophilic infiltrate, subepithelial edema, goblet cell hyperplasia, and basement membrane thickness. Blood levels of eosinophils and basophils were also measured prior to surgery on both primary and recurrent disease. Methods Thirty-two consecutive adult patients with nasal polyposis treated with primary surgery who subsequently underwent revision surgery were retrospectively enrolled. Results At primary surgery, a significant positive correlation (all p<0.05) emerged between all histopathological parameters, and between tissue eosinophil and blood eosinophil counts. A positive correlation between subepithelial edema scores and blood basophil levels (p<0.025) also came to light. At revision surgery, only basement membrane thickness correlated positively with: (i) tissue eosinophil count; and (ii) goblet cell hyperplasia (both p=0.001). In recurrent disease, there was again a positive correlation between eosinophil counts in tissue and blood (p<0.05). The mean tissue eosinophil count in recurrent CRSwNP was significantly lower than in the primary disease (p<0.001). Conclusions Our preliminary results support the hypothesis that tissue remodeling due to surgical and medical treatments for CRSwNP is a dynamic process involving important differences in tissue eosinophil counts between primary and recurrent CRSwNP. How tissue remodeling evolves after CRSwNP treatment warrants further investigation, not only in larger series of patients, but also after stratifying patients by the time elapsing since their treatment.