It is most commonly encountered in adults and rare in children. Polyps are the most common expansile lesions of the nasal cavity . Incidence increases in patients with conditions known to be associated with polyps such as infectious rhinosinusitis, cystic fibrosis, aspirin sensitivity, allergic fungal sinusitis, asthma and nickel exposure .
Clinical symptoms may include progressive nasal obstruction, rhinorrhea, facial pain, headache, anosmia, etc . It can also cause a particular pattern of chronic sinusitis as a result of obstruction of the drainage pathways of the paranasal sinuses.
Polyps are formed by the influx of fluid into the lamina propria of the sinonasal Schneiderian mucosa .
- extensive mucosal polyps occupying and obliterating the nasal cavity and the paranasal sinuses
- usually, they are hypodense, but may be hyperdense due increased protein content or fungal infection
- associated local benign bone remodeling or erosion (as opposed to a mucocele where the entire sinus is expanded )
- enlargement of infundibula
- attenuation of the ethmoid sinus walls and nasal septum
- occasionally sparing of the inferior nasal meatus
- truncation of middle turbinate
- opacified ethmoid sinuses with convex lateral walls and air-fluid levels
- a concurrent fungal sinus infection may be present
- sinonasal retention cyst
- can be indistinguishable
- usually spares the nasal cavity
- allergic fungal sinusitis
- commonly associated with polyps
- hyperdense central areas
- MRI may show low T1 and T2 signal
- granulomatosis with polyangiitis
- centered in the nasal cavity