Which of the following is the most common histological type of benign nasal polyp?

Explanation

## Histological Classification of Nasal Polyps **Key Point:** Inflammatory fibroid polyps (also called eosinophilic polyps or allergic polyps) are the most common benign nasal polyps, accounting for >90% of all nasal polyps. ### Histopathological Features - Edematous stroma with sparse inflammatory infiltrate - Lined by intact respiratory epithelium - Rich in eosinophils and mast cells - Absence of mucoserous glands in the polyp body ### Comparison of Common Nasal Polyps | Polyp Type | Frequency | Origin | Key Feature | Malignant Potential | |---|---|---|---|---| | Inflammatory fibroid | >90% | Maxillary/ethmoid sinus | Eosinophil-rich stroma | None | | Antrochoanal | 4–6% | Maxillary sinus | Extends into nasopharynx | Low | | Inverted papilloma | Rare | Lateral nasal wall | Intact epithelium inverts into stroma | High (5–15%) | | Allergic fungal | Rare | Ethmoid/sphenoid | Fungal elements + eosinophils | None | **High-Yield:** Inflammatory fibroid polyps are almost always benign and do not require oncologic surveillance, unlike inverted papillomas. **Clinical Pearl:** The term "allergic polyp" is a misnomer—these polyps are not truly allergic in origin but represent a chronic inflammatory response, often associated with allergic rhinitis or asthma. [cite:Scott-Brown's Otorhinolaryngology Ch 5]