## Site of Origin of Nasopharyngeal Angiofibroma **Key Point:** Nasopharyngeal angiofibroma (NAF) arises almost exclusively from the posterolateral wall of the nasopharynx, specifically near the sphenopalatine foramen and the junction of the vomer and sphenoid rostrum. ### Embryological Basis The tumor originates from embryonic remnants at the junction of the sphenoid bone and vomer, where the sphenopalatine artery enters the nasopharynx. This explains why the mass typically extends into the pterygopalatine fossa and may involve the sphenoid sinus secondarily. ### Clinical Significance 1. **Vascular supply**: Primarily from the sphenopalatine artery (terminal branch of maxillary artery) 2. **Extension pattern**: Grows posteriorly into pterygopalatine fossa, then into infratemporal fossa and skull base 3. **Surgical approach**: Knowledge of origin site guides endoscopic resection via transnasal approach **High-Yield:** The posterolateral nasopharyngeal origin near the sphenopalatine foramen is pathognomonic for NAF and is tested frequently in NEET PG. **Clinical Pearl:** Tumors arising from other sites (sphenoid mucosa, roof, anterior wall) are extremely rare and would suggest alternative diagnoses such as hemangioma, lymphoma, or other nasopharyngeal masses. ### Differential Sites (Why They Are Wrong) | Site | Frequency | Typical Pathology | | --- | --- | --- | | Posterolateral nasopharynx (sphenopalatine) | 95–99% | Angiofibroma | | Sphenoid sinus | Rare secondary involvement | Not primary origin | | Roof of nasopharynx | <1% | Other tumors (lymphoma, carcinoma) | | Anterior nasopharynx | <1% | Carcinoma, adenoma | [cite:Dhingra ENT 8e Ch 15]
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