Fact-sheet: Nasal polyp
Updated on 04/18/2017 at 6:59 AM
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Definition
The antrochoanal polyp, or Killian's polyp, is a solitary inflammatory sinonasal polyp arising in the maxillary sinus and then extending into the nasal cavity through the maxillary ostium or an accessory ostium.
Sphenochoanal or ethmochoanal polyps also exist, but are rarer.
Etiopathogenesis is debated (cystic, allergic, and inflammatory theories)
Clinical features
Presents with nasal obstruction associated with rhinorrhea, or in the setting of snoring.
Most often discovered in adolescence, predominantly in males.
Progression is slow.
Nasal endoscopy reveals a translucent mass, resembling any other polyp, but with a pedicle arising from a sinus. It may show scattered vascular markings if large
CT
Dumbbell-shaped mass arising from a sinus and extending into a nasal cavity, with a narrow pedicle through a sinus ostium.
Low density, mucoid type.
Peripheral enhancement.
Usually no bone lysis, but may show a expansile, remodeling appearance.
Complete opacification of the ipsilateral sinus giving a sinusitis-like appearance, which would warrant MRI if an incidental finding, though CT is usually sufficient for preoperative workup in the absence of clinical uncertainty.
MRI
Morphologically identical.
Marked, fluid-like T2 hyperintensity
T1 hyposignal
Enhancement of the peripheral mucosa without central enhancement of the edematous lamina propria
Management
Surgical resection as complete as possible including the antral base, nowadays via an endoscopic approach.
