Sphenochoanal polyp: an endoscopic view.

A 34-year-old man was referred to us with a 1-year history of right-sided headache and intermittent nasal discharge and a 4-month history of right-sided nasal obstruction. He had been treated with several antibiotics and analgesics by his general physician prior to the referral.

On anterior rhinoscopy, no obstruction was seen in the anterior nasal cavities, including the middle meatus bilaterally. However, nasal endoscopy revealed that a large polypoid mass had filled the fight superior nasal cavity and extended into the posterior choana (figure 1). The stalk of the polyp was communicating with the fight sphenoid ostium through a pedicle. T2-weighted magnetic resonance imaging (MRI) demonstrated hyperintensity in the sphenoid sinus on the right, suggesting an inflamed mucosal polyp (figure 2). The hyperintense mucosal polyp was also seen posteriorly in the right nasal cavity. The other paranasal sinuses were clear.

[FIGURES 1-2 OMITTED]

On the basis of these nasal endoscopic and MRI findings, we established a diagnosis of sphenochoanal polyp. The patient was taken to the operating room for right endoscopic sinus surgery and transnasal sphenoidotomy. At surgery, the superior portion of the polyp was traced to the right sphenoid ostium. The inferior choanal portion and the pedicle were removed transnasally with a grasping cup forceps. The sphenoid sinus ostium was enlarged, and the anterior wall of the sinus was resected to remove the intrasinusoidal part completely with an upward, through-cutting forceps. To prevent recurrence, the intrasinusoidal portion of the polyp was removed completely along with the nasal part.

Histopathology confirmed that the lesion was an inflammatory polyp. At 6-month follow-up, the patient was symptom-free, and endoscopy detected no evidence of recurrence.

Sphenochoanal polyps are rare. These masses, which arise from the paranasal sinuses and pass through the sinus ostia into the nasal cavity or hang on a large pedicle in the nasopharynx, are defined as choanal polyps. (1) Most choanal polyps arise in the maxillary sinus; on rare occasions, one will originate in the sphenoid or ethmoid sinus. (2-4) Only one case of simultaneous antrochoanal and sphenochoanal polyps has been reported in the literature. (5) Unlike antrochoanal polyps, sphenochoanal polyps have a higher chance of exhibiting neoplastic pathology. (6) They have a variety of anatomic origins. Although most sphenochoanal polyps arise in the sphenoid ostium, some have originated in adjacent areas and in the sphenoid sinus. (6)

Anterior rhinoscopy does not allow for visualization of the sphenoethmoid recess, but nasal endoscopy provides a clear view of the sphenoethmoid recess and the postnasal space. Therefore, a definitive diagnosis can be made during nasal endoscopy by identification of the sinus ostium from which the stalk of the polyp passes through. Downward extension of intracranial pathology must also be considered. Computed tomography and MRI are valuable tools for making the differential diagnosis. Sphenochoanal polyps are treated surgically, and endoscopic techniques are widely used for their removal.

References

(1.) Berg O, Carenfelt C, Silfversward C, Sobin A. Origin of the choanal polyp. Arch Otolaryngol Head Neck Surg 1988; 114:1270-1.

(2.) Ileri F, Koybasioglu A, Uslu S. Clinical presentation of a sphenochoanal polyp. Eur Arch Otorhinolaryngol 1998;255:138-9.

(3.) Weissman JL, Tabor EK, Curtin HD. Sphenochoanal polyps: Evaluation with CT and MR imaging. Radiology 1991;178:145-8.

(4.) Yanagisawa K, Ho SY, Yanagisawa E. Endoscopic view of a sphenochoanal polyp. Ear Nose Throat J 2000;79:546-8.

(5.) Ozcan M, Ozlugedik S, Ikinciogullari A. Simultaneous antrochoanal and sphenochoanal polyps: A rare clinical entity. J Laryngol Otol 2005;119:152-4.

(6.) Sethi DS, Lau DP, Chee LW, Chong V. Isolated sphenoethmoid recess polyps. J Latyngol Otol 1998;112:660-3.

Sampan Singh Bist, MS; Manisha Bisht, MBBS; Rajesh Kumar, MS; Saurabh Varshney, MS

From the Department of ENT, Himalayan Institute of Medical Sciences, Dehradun, Uttaranchal, India.