A nasal polyp that originates from the maxillary sinus, extends through the maxillary ostium into the nasal cavity, and may prolapse into the nasopharynx and oropharynx is classified as which type?

Explanation

## Antrochoanal Polyp: Definition and Clinical Features **Key Point:** Antrochoanal polyp (also called Killian polyp) is a benign polyp that originates in the maxillary sinus and extends through the maxillary ostium into the nasal cavity, often prolapsing into the nasopharynx and oropharynx. ### Epidemiology and Origin - **Frequency:** Accounts for 4–5% of all nasal polyps - **Age of presentation:** Usually in children and young adults (5–30 years) - **Origin:** Arises from the mucosa of the maxillary sinus near the maxillary ostium - **Unilateral:** Always unilateral presentation (unlike inflammatory polyps) ### Pathological Pathway ```mermaid flowchart TD A[Maxillary sinus mucosa]:::outcome --> B[Polyp formation at ostium]:::outcome B --> C[Extends through maxillary ostium]:::action C --> D[Enters nasal cavity]:::action D --> E[Prolapse into nasopharynx/oropharynx]:::action E --> F[Presents with nasal obstruction, post-nasal drip, or oropharyngeal mass]:::outcome ``` ### Clinical Presentation - **Nasal obstruction** (unilateral) - **Post-nasal drip** - **Oropharyngeal mass** (if prolapsed into oropharynx) - **Epistaxis** (less common) ### Diagnosis and Management - **Imaging:** CT scan shows polyp originating from maxillary sinus - **Treatment:** Surgical removal (endoscopic marsupialization or complete excision) - **Recurrence:** Low recurrence rate if completely removed **High-Yield:** The key distinguishing feature is the **origin in the maxillary sinus** with **unilateral presentation** and **potential prolapse into the nasopharynx/oropharynx**. This is the pathognomonic presentation of antrochoanal polyp. **Clinical Pearl:** A patient presenting with a mass visible in the oropharynx that appears to be a nasal polyp should raise suspicion for antrochoanal polyp with prolapse into the oropharynx.