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

Explanation

## Histological Classification of Nasal Polyps **Key Point:** Inflammatory (eosinophilic) polyps account for approximately 90% of all nasal polyps and are the most common type encountered in clinical practice. ### Characteristics of Inflammatory Polyps - Benign, non-neoplastic growths - Arise from mucosa of nasal cavity and paranasal sinuses - Histology shows edematous stroma with variable eosinophilic infiltration - Associated with chronic rhinosinusitis, allergic rhinitis, and aspirin sensitivity - Typically bilateral and multiple ### Other Nasal Polyp Types | Polyp Type | Frequency | Key Features | Malignant Potential | |---|---|---|---| | **Inflammatory (Eosinophilic)** | 90% | Bilateral, edematous, eosinophil-rich | None | | **Antrochoanal** | 4–5% | Unilateral, arises from maxillary antrum, extends into nasopharynx | None | | **Allergic Fungal Sinusitis** | 1–2% | Fungal colonization, eosinophil-rich, polypoidal masses | None | | **Inverted Papilloma** | <1% | Unilateral, intact basement membrane, risk of malignant transformation | High (5–15%) | **High-Yield:** Inverted papilloma is rare but MUST be recognized because of its malignant potential and need for aggressive management and surveillance. **Clinical Pearl:** Bilateral nasal polyps in a child should raise suspicion for cystic fibrosis; sweat chloride testing is indicated. [cite:Scott-Brown's Otolaryngology 8e]