| disease | Maxillary Sinus Choanal Polyp |
The antrochoanal polyp is a polyp that originates in the maxillary sinus, has a slender stalk, and protrudes backward into the nasal cavity. This type of polyp has its own pathological and clinical characteristics and is generally considered to be a distinct pathological entity from the common nasal polyp. The condition is more common in adolescents, with no difference in incidence between males and females.
bubble_chart Pathological Changes
The cause of the disease remains unclear. The polyp originates in the maxillary sinus, then extends through the sinus ostium in the middle nasal meatus with a slender stalk into the nasal cavity, sliding backward toward the choana and potentially protruding into the nasopharynx. Stammberger (1986) used nasal endoscopy to observe that the polyp originates near the upper inner corner of the sinus ostium within the maxillary sinus cavity. Kamel (1990) employed endoscopy in 22 cases of choanal polyps and found that 13 originated from the medial wall of the maxillary sinus, while the other 9 cases had extensive mucosal involvement, making the origin difficult to determine. Berg (1988) explored the maxillary sinus in 15 cases of choanal polyps and discovered that the polyps were connected to cysts in the sinus wall. He thus proposed that choanal polyps originate from cysts in the maxillary sinus wall, which gradually enlarge, protrude through the sinus ostium into the nasal cavity, and eventually form choanal polyps. Histological examination revealed that polyp tissue often contains numerous mucous acini, sometimes forming a large cyst. Cellular infiltration primarily consists of a small number of plasma cells, with rare eosinophil infiltration.
The clinical feature of a posterior nasal polyp is its solitary nature, so unilateral progressive nasal obstruction is its main symptom. Initially, the patient feels something moving in the nose with breathing, gradually noticing that inhalation is tolerable but exhalation is difficult. If the polyp protrudes into the nasopharynx and continues to grow, it can cause bilateral nasal obstruction. If the polyp becomes very large, it may descend into the oropharynx and cause a foreign body sensation.
bubble_chart Auxiliary Examination
Anterior rhinoscopy often reveals a grayish-white, smooth pedicle extending posteriorly. If the nasal turbinates are sufficiently contracted with an Ephedrine-soaked cotton pad, the pedicle can be seen originating from the middle meatus, and palpation shows it to be soft and mobile. Posterior rhinoscopy may reveal a translucent polyp, pale red or grayish-white in color, located in the posterior nasal cavity or nasopharynx. Polyps that have prolapsed into the pharynx are more easily visualized when the soft palate is elevated.
X-ray examination may show thickening of the mucous membrane in the affected maxillary sinus, and occasionally a semicircular shadow of a small cyst.
Diagnosis can be easily made through anterior and posterior rhinoscopy combined with medical history. However, for juvenile patients, differentiation from nasopharyngeal angiofibroma should be noted, as the latter has a firmer texture. Pathological biopsy should not be performed hastily for this differentiation.
bubble_chart Treatment Measures
The treatment of choanal polyp originating from the maxillary sinus is primarily surgical. The nasal portion can be removed by snaring and pulling out its pedicle. If the polyp is too large to be extracted through the anterior naris, its stalk can be severed near the middle meatus, allowing the large choanal polyp to be expelled through the pharynx. However, preventive measures must be taken beforehand to avoid the polyp falling into the laryngopharynx. It is preferable to enter the nasopharynx from the oropharynx under posterior rhinoscopy, grasp the polyp with forceps, and extract it.
