Sphenochoanal polyps originate from within the sphenoid sinus and extend into the choana. There are a few descriptions in the literature of an isolated choanal polyp arising from the external face of the sphenoid. These spheno-ostio-choanal polyps occur in the setting of an otherwise normal sphenoid sinus; they are a curious entity.
Choanal polyps represent only approximately 4% to 6% of all nasal polyps.1 Most commonly, these large solitary polyps arise from the antrum of the maxillary sinus and are referred to as antrochoanal polyps; however, more rare variants of choanal polyps include those that arise from within the sphenoid and ethmoid sinuses. A sphenochoanal polyp originates from within the sphenoid sinus and extends through the ostium into the choana; polyps arising from the mucosa adjacent to the sphenoid ostium externally also have been described.2 These polyps, which occur in the setting of an otherwise normal sphenoid sinus and are more aptly termed spheno-ostio-choanal, are an exceedingly rare and curious entity. We describe the first report, to our knowledge, of isolated, bilateral spheno-ostio-choanal polyps causing nasal obstruction. We obtained approval from the institutional review board of the Saint Louis University School of Medicine.
Sindwani R, Marino M. The Spheno-Ostio-Choanal PolypA Rare and Curious Entity. Arch Otolaryngol Head Neck Surg. 2010;136(8):834-835. doi:10.1001/archoto.2010.120