Histopathological Characteristics and Inflammatory Cell Infiltration in Sinonasal Inverted Papilloma

Area of Science:

• Otorhinolaryngology
• Pathology
• Immunology

Background:

• Sinonasal inverted papilloma (SNIP) is a benign epithelial tumor with poorly understood inflammatory roles.
• Characterizing inflammation in SNIP is crucial for understanding its pathogenesis.

Purpose of the Study:

• To compare histopathological patterns and inflammatory markers of SNIP.
• To differentiate SNIP from chronic rhinosinusitis with nasal polyps (CRSwNPs) and normal ethmoid mucosa.

Main Methods:

• Analyzed 58 tissue biopsies from SNIP, CRSwNP, and normal ethmoid sinus groups.
• Assessed epithelial remodeling markers (p63, CK5) and inflammatory cell infiltration (neutrophils, macrophages, eosinophils).
• Quantified cytokine levels (IL-1β, IL-6, TNF-α) using immunohistochemistry.

Main Results:

• SNIP exhibited significantly higher expression of p63 and CK5 compared to other groups.
• Increased neutrophil and macrophage infiltration was observed in SNIP, varying across grades.
• Elevated inflammatory cytokine levels were found in SNIP compared to CRSwNP, with a positive correlation between p63 and cytokines.

Conclusions:

• Excessive epithelial remodeling is a key feature of SNIP.
• SNIP is associated with significant sinonasal mucosal inflammation.
• Distinct inflammatory and remodeling profiles differentiate SNIP from CRSwNP.