Antrochoanal polyp arises from which anatomical site?

Explanation

## Antrochoanal Polyp: Anatomical Origin **Key Point:** Antrochoanal polyps originate from the lateral wall of the maxillary sinus, typically near or at the maxillary ostium, and extend through the ostiomeatal complex into the nasopharynx. ### Pathogenesis and Anatomy ```mermaid flowchart TD A[Lateral wall of maxillary sinus<br/>near ostium]:::action --> B[Polyp grows through<br/>ostiomeatal complex]:::action B --> C[Extends into nasal cavity]:::action C --> D[Protrudes into nasopharynx<br/>via choana]:::outcome D --> E[Presents as unilateral<br/>nasopharyngeal mass]:::outcome ``` ### Distinguishing Features of Antrochoanal Polyps | Feature | Antrochoanal Polyp | Inflammatory Fibroid Polyp | |---|---|---| | **Origin** | Maxillary sinus (lateral wall) | Ethmoid sinuses | | **Laterality** | Unilateral (95%) | Bilateral and multiple | | **Location** | Extends into nasopharynx | Confined to nasal cavity | | **Age of onset** | Younger patients (10–30 years) | Any age | | **Histology** | Myxoid stroma, sparse eosinophils | Edematous stroma, abundant eosinophils | | **Recurrence rate** | 5–10% (if stalk not removed) | 10–30% | **High-Yield:** The key to diagnosis is that antrochoanal polyps present as a **unilateral nasopharyngeal mass** that can be traced back to the maxillary sinus origin via the ostiomeatal complex. **Clinical Pearl:** Patients with antrochoanal polyps often present with unilateral nasal obstruction and may have a visible mass in the nasopharynx on endoscopy. **Mnemonic:** **ACE** — **A**ntrochoanal, **C**hoana, **E**xtends (from maxillary sinus through ostiomeatal complex to nasopharynx). [cite:Dhingra ENT 8e Ch 8]