Background

Nasal polyps are very common and are divided into three types.

Type of Polyp	Characteristics
Inflammatory polyps	Most common Usually multiple and bilateral Usually >30 yrs Association with asthma or chronic rhinitis Translucent, moist surface
Nasal polyps in cystic fibrosis	20% of children with cystic fibrosis Grossly resemble inflammatory polyps
Antrochoanal polyps	Originates from the wall of the maxillary antrum connected with a long narrow stalk Extends along the choana into nasopharynx 4-6% of all nasal polyps Frequent in childhood 90% are solitary

Under the microscope, there are similar findings for all three polyp types.

Type of Polyp	Histology
Inflammatory polyps	Localized outgrowths of the lamina propria with edema Basement membrane thickened Variable mixture of inflammatory cells Neutral mucin
Nasal polyps in cystic fibrosis	Lack basement membrane thickening Few stromal eosinophils Mucous glands and cysts contain predominately acid mcuin
Antrochoanal polyps	Lack basement membrane thickening Stroma is less edematous and more fibrotic than inflammatory polyps Large vascular spaces may be present Patchy inflammation

The pathologist is sometimes faced with the presence of atypical cells within the stroma of these nasal polyps. These cells are most common in polyps from younger patients and also in polyps with a prominent fibrous stroma. They are most common in antrochoanal polyps and are composed of hyperchromatic nuclei with a spindled or multinucleated appearance concentrated in the submucosal region or near small vascular channels. Mitotic figures are rare and the cellularity is not increased, contrasting with a malignant sarcoma such as a rhabdomyosarcoma.

Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.

Nasopharynx

• Inflammatory polyp-Microscopic Photo
  

Last Updated 4/1/2001

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