Mucosal surface shows squamous metaplasia with adjacent surface ulceration of the polyp.

Normal mucosa (bottom left) and submucosa blends with the polyp vasculature (right)

Variably sized vessels with fibrosis and chronic inflammation comprise the polyp.

Eosinophilic thick-walled vessels with mild chronic inflammation and fibrotic stroma.

Another area demonstrates similar features. Sometimes the stromal cells exhibit mild atypia, thought to be a degenerative feature.

A distinctive polyp that originates in the maxillary sinus and grows into the nasal cavity. They represent approximately 4-6% of all sinonasal polyps.1 Compared to conventional sinonasal polyps, antro-choanal polyps are less translucent, more fibrotic with a reduced number of mucoserous glands.

Occurs more often in men, and typically presents as a single, unilateral polyp with obstruction. These polyps are often also associated with maxillary sinusitis and typical sinonasal polyps.

Excision is curative. May recur if the stalk is incompletely excised.

• Sinonasal : Sinonasal Polyp