Endoscopic view of a sphenochoanal polyp.

A 14-year-old white girl complained of constant nasal congestion and upper airway obstruction that manifested as mouth breathing. She had experienced several sinus infections per year. Anterior rhinoscopy showed no obstruction of the anterior nasal cavities, including the middle meatus bilaterally. However, nasal endoscopy revealed that a large mass was obstructing the entire nasopharynx and suggested that a choanal polyp might be emanating from the left side. Adenoid x-ray showed a large soft tissue mass in the nasopharynx. Coronal sinus computed tomography (CT) demonstrated a polypoid mass originating in the left sphenoid sinus and extending down to the nasopharynx through the area of the sphenoethmoid recess (figure, A and B). There was mild mucoperiosteal thickening in the left ethmoid sinuses, but otherwise the paranasal sinuses were clear.

At surgery, nasal endoscopy detected complete obstruction of the nasopharynx by a large sphenochoanal polyp (figure, C). The superior portion of the polyp was traced to the left sphenoid ostium.

Resection of the sphenochoanal polyp began with amputation of the choanal portion of the polyp with a microdebrider (figure, D). The inferior choanal portion of the polyp was removed transnasally with a grasping cup forceps (figure, E and F). The superior portion of the polyp was excised with a microdebrider (figure, G). The polyp was clearly found to originate in the left sphenoid sinus; there was no connection to the middle meatus or maxillary sinus ostium (figure, H). The sphenoid sinus ostium was enlarged with a microdebrider, and the polyp was seen to originate in the anterior roof of the sinus (figure, I). The polyp was completely removed with a microdebrider and an upward, through-cutting forceps. One year after surgery, the patient remains symptom-free and without evidence of recurrence.

Isolated sphenochoanal polyps are rare. [1,3] Although most sphenochoanal polyps arise in the sphenoid ostium, some have been reported to originate in adjacent areas and in the sphenoid sinus. [1] Sphenochoanal polyps are difficult to document. Anterior rhinoscopy does not allow for visualization of the sphenoethmoid recess. Nasal endoscopy must be performed to examine the sphenoethmoid recess, and it serves as the primary diagnostic tool.

A sphenochoanal polyp should be suspected in cases of persistent difficult nasal breathing and recurrent sinusitis despite proper medical therapy. Diagnosis of a sphenochoanal polyp can be made by transnasal endoscopy with a rigid telescope or a flexible fiberscope, by transoral nasopharyngoscopy, and by CT. Unlike antrochoanal polyps, sphenochoanal polyps have a higher chance of exhibiting neoplastic pathology, most often inverted papillomas. [1]

Downward extension of intracranial pathology must also be considered. CT and/or magnetic resonance imaging serve as invaluable tools in these cases for making the differential diagnosis. Differential diagnoses include antrochoanal polyp, hypertrophied adenoids, thornwaldt's s cyst, pituitary tumor, lymphoma, and carcinoma. [4]

Endoscopy-assisted powered dissection is the most effective surgical treatment for a sphenochoanal polyp.

From the Southern New England Ear, Nose, Throat, and Facial Plastic Surgery Group (Dr. K. Yanagisawa and Dr. E. Yanagisawa); the Section of Otolaryngology, Yale University School of Medicine (Dr. K. Yanagisawa, Dr. Ho, and Dr. E. Yanagisawa); and the Section of Otolaryngology, Hospital of St. Raphael (Dr. K. Yanagisawa and Dr. E. Yanagisawa), New Haven, Conn.

References

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

(2.) Hayes E, Lavelle W. Sphenochoanal polyp: CT findings. J Comput Assist Tomogr 1989;13:365-6.

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

(4.) Yanagisawa E, Yanagisawa K. Endoscopic view of Thornwaldt cyst of the nasopharynx. Ear Nose Throat J 1994;73:884-5.