Background: Nasal inverted papilloma (NIP) is defined based on its histological characteristic of inverted epithelium growth into the stroma. The inversion can result in epithelial growth in the underlying connective tissue stroma when the basement membrane completely separates from the epithelial layer. To date, such inversion mechanism underlying NIP's pathological phenomenon is unknown. Therefore, we hypothesized that mediators and soluble proteins released by neutrophils, the most predominant infiltrating cells in NIP, is vital in causing the epithelial changes and pathogenesis of NIP. Methods: We collected 37 NIP tissues from patients who underwent surgical removal of NIP and performed hematoxylin-eosin (HE), immunohistochemical, and immunofluorescence staining to analyze in-depth the basic characteristics of NIP, including detecting the expression and distribution of MMPs and associated factors in NIP. Western blotting and quantitative real-time PCR were further performed to analyze the protein and mRNA expression levels of specific factors including MMPs, HIF-1α, and tissue inhibitors of metalloproteinases (TIMPs). Results: We observed finger-like projections that insert into the epithelium in NIP tissue as its main characteristics. The projections contain fibroblasts, extracellular matrix, capillaries, and infiltrating inflammatory cells. We found abundant neutrophils clustered at the finger-like projection of NIP, and also noted MMP-1 and MMP-9 were up-regulated in NIP (p<0.05), whereas TIMP-1/3 was decreased. The expression level of HIF-1α was also found to be increased in NIP tissue. We further showed that MMP-9 and HIF-1α were mainly expressed by neutrophils and were predominantly observed in the finger-like projections that contribute to the NIP pathology. Conclusion: Upregulation and release of MMP-9 and HIF-1α from infiltrating neutrophils may cause damage to the epithelial basement membrane and epithelial clefts, forming fingerlike projections with angiogenesis and fibroblasts insertion, resulting in epithelial growth in the tissue stroma, a typical histo-pathological characteristic in NIP.

Clinicians should be aware of lung function decline in nasal polyps patients, especially in those with tissue eosinophilia.

Background Visual Analog Scale (VAS) as determined by the patient is recommended by the European Position Paper on Rhinosinusitis and Nasal Polyps 2012 in evaluation of the total severity of the chronic rhinosinusitis (CRS) patients’ symptoms. Objective To evaluate the correlation between evaluations performed by otorhinolaryngologists and CRS patients with commonly used systems. Methods Scores of VAS and Sino-Nasal Outcome Test-20 (SNOT-20) Chinese version were obtained from 110 CRS patients with nasal polyps (CRSwNPs, n = 61) and without nasal polyps (CRSsNPs, n = 49) before surgery, which were compared with scores of Lund–Kennedy endoscopic staging system, the Lund–Mackay computed tomography (CT) staging system, and VAS from 3 attending otorhinolaryngologists. Results The median VAS scores given by CRS patients (6.0; 4.25–7.5) do not correlate significantly with the VAS scores by the 3 otorhinolaryngologists (5.5; 4.83–6.5) with a correlation coefficient of .218 (−0.146 to 0.466). For CRS patients, there was only a moderate correlation between scores of VAS and the SNOT-20 ( r = .37), and no significant difference of VAS scores between CRSwNP and CRSsNP, and between unilateral and bilateral nasal polys. For otorhinolaryngologists, a higher median VAS score was found in CRSwNP (6.0; 5.17–7.0), especially in bilateral (6.0; 5.0–7.08) and revision surgery (6.08; 5.33–7.63). The VAS scores of otorhinolaryngologists correlated significantly with the Lund–Mackay CT score ( r = .7536) and Lund–Kennedy endoscopic staging ( r = .5947). Conclusions VAS scores between patients and physicians are not correlated significantly in this study, but they fall within the same therapeutic range and do not change the clinical management of the patients.

Our study has confirmed that the therapeutic effects of ESS on olfactory function last for up to 6 months, particularly in patients with CRSwNP. Although the therapeutic effects plateaued at 3 months postoperatively, the olfactory function continues to recover between 3 and 6 months.

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