An antrochoanal polyp is a benign polyp that typically has its stalk in the maxillary sinus (The “cheek” sinus located below the eye). The polyp enlarges until it passes out of the sinus and into the nasal cavity. These masses can grow to be quite large and may distort the surrounding anatomy. Once they grow into the choana (the pathway through which air passes from the nose into the throat), patients’ symptoms may worsen as nasal breathing becomes increasingly difficult. Sometimes the polyp may actually extend all the way to the opposite choana and block nasal breathing from both sides.