A 35-year-old man with a 2-year history of nasal obstruction and rhinorrhea presents with bilateral nasal masses. Endoscopy reveals smooth, pale, gelatinous polyps arising from the lateral nasal wall. A 28-year-old woman with cystic fibrosis presents with similar nasal obstruction and is found to have bilateral nasal polyps on examination. Which feature best distinguishes antrochoanal polyps from cystic fibrosis-associated nasal polyps?

Explanation

## Discriminating Features: Antrochoanal vs. CF-Associated Polyps ### Key Anatomical Distinction **Key Point:** Antrochoanal polyps originate from a single stalk in the maxillary sinus and extend through the maxillary ostium into the nasopharynx, whereas CF-associated polyps are typically bilateral, multiple, and arise from diffuse sinonasal mucosa. ### Comparative Table | Feature | Antrochoanal Polyp | CF-Associated Polyps | |---------|-------------------|----------------------| | **Laterality** | Unilateral (90%) | Bilateral (80%) | | **Origin** | Single stalk from maxillary sinus | Multiple sites, diffuse mucosa | | **Number** | Single or few | Multiple small polyps | | **Age of onset** | 20–40 years | Childhood (< 10 years) | | **Associated condition** | Isolated (no systemic disease) | Cystic fibrosis | | **Histology** | Mature fibrous tissue, minimal inflammation | Eosinophil-rich, allergic inflammation | | **Treatment** | Surgical excision of stalk | Medical (topical steroids) + address CF | ### Clinical Pearl **Clinical Pearl:** The pathognomonic finding in antrochoanal polyps is the **single stalk origin from the maxillary sinus** with extension into the nasopharynx. This unilateral, single-origin pattern is the gold standard discriminator. CF-associated polyps, by contrast, are almost always bilateral and multiple, reflecting the underlying mucus plugging and chronic inflammation affecting the entire sinonasal tract. ### High-Yield Mnemonic **Mnemonic:** **ACE** = **A**ntrochoanal = **C**areful **E**xcision of stalk (single origin, unilateral). ### Imaging Correlation CT or MRI of antrochoanal polyps shows a pedunculated mass with a clear stalk arising from the maxillary sinus, often with widening of the maxillary ostium. CF polyps show diffuse, bilateral sinonasal involvement without a discrete stalk. [cite:Bhattacharyya 2014 Otolaryngology]