Sphenochoanal polyp presenting with concomitant nasal polyps.

Abstract

A sphenochoanal polyp is a rare lesion that originates in the sphenoid sinus. It occurs most often in adolescents and young adults. We present what to the best of our knowledge is the first reported case of a sphenochoanal polyp associated with concomitant nasal polyps. The patient was a 54-year-old man who presented with bilateral nasal obstruction, possible obstructive sleep apnea, and an altered voice, all of which had likely been caused by the presence of a massive left sphenochoanal polyp and bilateral grade III anterior and posterior ethmoid polyps. Because the patient had dilated cardiomyopathy, he was not a good candidate for general anesthesia. Therefore, the polyps were removed endoscopically under local anesthesia. The sphenochoanal polyp measured 7.5 cm in its greatest dimension and weighed 41 g. The patient remained symptom-free at the 1-year follow-up. The presentation of a sphenochoanal polyp is similar to that of the more common antrochoanal polyp, but the two can usually be differentiated on computed tomography. Endoscopic sinus surgery allows for complete removal of the polyp, including its site of origin, which minimizes the risk of recurrence.

Introduction

Choanal polyps are benign masses that protrude through the choana into the nasopharynx. They are classified as antrochoanal and sphenochoanal, depending on the sinus of origin. Antrochoanal polyps arise from the maxillary sinus and are more common; they account for 3 to 6% of all polyps. (1) Sphenochoanal polyps are rare, and all reported cases have involved solitary polyps. Most reported sphenochoanal polyps have occurred in adolescents and young adults. (2) Histologically, the two types are similar in appearance, but they can usually be differentiated on computed tomography (CT). (3) We describe what, to the best of our knowledge, is the first reported case of a massive sphenochoanalpolyp that was accompanied by nasal polyps. We also discuss the use of CT in distinguishing between sphenochoanal and antrochoanal polyps and the use of an endoscopic approach for their safe removal.

Case report

A 54-year-old man presented with a 2-year history of bilateral nasal obstruction, worsening snoring, daytime somnolence, and altered voice (rhinolalia clausa). He was forced to sleep sitting up because the upper airway obstruction would not allow him to breathe when he was lying down. He was diabetic, hypertensive, and had dilated cardiomyopathy. His body mass index was 33. The nasal obstruction had been treated with betamethasone drops, but they were ineffective.

On examination, a huge polyp could be seen passing from the nasopharynx down into the oropharynx. Bilateral grade III nasal polyps were also observed. CT of the paranasal sinuses revealed a large soft-tissue opacity in the nasopharynx (figure 1, A) that had its origin in the left sphenoid sinus (figure 1, B). CT also demonstrated a complete opacification of the maxillary sinuses and a partial opacification of the ethmoid sinuses (figure 1, C). The right sphenoid sinus was clear.

[FIGURE 1 OMITTED]

An anesthetist determined that because of the patient's cardiomyopathy, general anesthesia would be extremely risky. Therefore, we decided to perform endoscopic sinus surgery with local anesthesia. Clinically, the patient had obstructive sleep apnea caused by the sphenochoanal polyp, but since his situation was urgent, we did not wait to perform polysomnography to document this.

The nose was sprayed with co-phenylcaine (1 ml of 5% lidocaine and 0.5% phenylephrine topical solution), and then pledgets soaked in Moffett's solution (3 ml of 8.4% sodium bicarbonate, 2 ml of 10% cocaine, and 1 ml of 1:1,000 epinephrine) were applied for more effective local anesthesia. (4) The patient was operated on while in a semi-sitting position, and he tolerated the procedure well. The ethmoid polyps were removed with a microdebrider, and anterior and posterior ethmoidectomies were performed. The pedicle of the sphenochoanal polyp was seen protruding through the left sphenoid ostium into the sphenoethmoid recess and extending into the choana. The ostium was widened to enable removal of the polyp via the oral cavity. The sphenochoanal polyp measured 7.5 x 4.5 x 3.0 cm, weighed 41 g, and was of firm consistency (figure 2). Histology revealed features of an inflammatory choanal polyp (figure 3).

[FIGURES 2-3 OMITTED]

Following surgery, the patient's nasal airway was clear. Postoperatively, he was able to sleep while lying down, he no longer snored or experienced daytime somnolence, and the quality of his speech improved considerably. He remained symptom-free at the 1-year follow-up.

Discussion

Most sphenochoanal polyps are not associated with other sinus disease, (1,5-8) although in some cases, other sinuses are affected, possibly as a result of blockage by the polyp. (9,10) Our case is unique in that the patient presented with concurrent nasal polyps, and it is unusual in that he presented at a relatively late age.

Although nasal polyps are commonly found in the nasopharynx, it is choanal polyps that may grow large enough to extend into the oropharynx. Choanal polyps have a firmer consistency than nasal polyps, owing to their extensive fibroblastic activity. Our patient had a typical sphenochoanal polyp that clearly originated as a solitary mass in the left sphenoidal mucosa. Choanal polyps are believed to arise from an expanding intramural cyst that protrudes through the ostium of the sinus into the nasal cavity. (3) The pathogenesis of the cyst may involve thrombosis of lymphatic vessels following sinus inflammation. (10)

Preoperative identification of the sinus from which a choanal polyp arises is important because the polyp's site of origin in the sinus must be resected in order to minimize recurrence. (8,11) This consideration may influence the surgical approach. (8,12) CT of the paranasal sinuses is necessary to identify the characteristic features of a sphenochoanal polyp so that it can be differentiated from an antrochoanal polyp and to determine the anatomic landmarks for endoscopic sinus surgery. The appearance of these polyps on CT has been well described. (8,12) Because most choanal polyps are not associated with other sinus disease, a finding of an opaque sphenoid sinus and a clear maxillary sinus is a likely indicator that the polyp is sphenochoanal, even if its origin cannot be clearly identified. (12) If both the sphenoid and maxillary sinuses are opaque, it is important to identify the continuity of the polyp with its origin at surgery. Antrochoanal polyps originate in the middle meatus; in contrast, a sphenochoanal polyp passes between the nasal septum and the middle turbinate, leaving the middle meatus clear. (12) If other polyps are present, as occurred in our patient, CT may not always allow for a determination of the polyp's exact site of origin.

Management of choanal polyps involves complete excision of the polyp, including its pedicle and its site of origin within a sinus. (10,12) Endoscopic sinus surgery offers excellent views of the involved sinuses, and it is associated with a lower recurrence rate than is simple polypectomy. (11) A polyp's site of origin is usually clear on intraoperative views.

To the best of our knowledge, no case of a sphenochoanal polyp with concomitant obstructive sleep apnea has been reported, and only 2 cases (13,14) of an antrochoanal polyp with obstructive sleep apnea have been reported. We have no sleep-study evidence that our patient did in fact have obstructive sleep apnea; we have only the characteristic history and clinical findings of a massive sphenochoanal polyp. However, our patient also had other nasal polyps. Therefore, we are unable to conclude that the probable obstructive sleep apnea was definitely caused by the sphenochoanal polyp. However, such a diagnosis is supported by the fact that the patient's symptoms improved significantly following surgery.

In conclusion, sphenochoanal polyps are rare. Endoscopic nasal examination and CT of the paranasal sinuses are usually able to allow for differentiation between sphenochoanal and antrochoanal polyps. Endoscopic sinus surgery can be diagnostic when this is in doubt and therapeutic in enabling complete removal of a sphenochoanal polyp, including its pedicle, to minimize recurrence.

References

(1.) Ryan RE Jr., Neel HB III. Antral-choanal polyps. J Otolaryngol 1979; 8:344-6.

(2.) Sirola R. Choanal polyps. Acta Otolaryngol 1966;61:42-8.

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

(4.) Benjamin E, Woug DK, Choa D. "Moffett's" solution: A review of the evidence and scientific basis for the topical preparation of the nose. Clin Otolaryngol Allied Sci 2004;29:582-7.

(5.) Tosun F, Yetiser S, Akcam T, Ozkaptan Y. Sphenochoanal polyp: Endoscopic surgery. Int J Pediatr Otorhinolaryngol 2001;58:87-90.

(6.) Dadas B, Yilmaz O, Vural C, et al. Choanal polyp of sphenoidal origin. Ear Arch Otorhinolaryngol 2000;257:379-81.

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

(8.) Spraggs PD. Radiological diagnosis of spheno-choanal polyp. J Laryngol Otol 1993;107:159-60.

(9.) Lopatin A, Bykova V, Piskunov G. Choanal polyps: One entity, one surgical approach? Rhinology 1997;35:79-83.

(10.) Crampette L, Mondain M, Rombaux P. Sphenochoanalpolypin children. Diagnosis and treatment. Rhinology 1995;33:43-5.

(11.) Eloy P, Evrard I, Bertrand B, Delos M. Choanal polyp of sphenoidal origin. Report of two cases. Acta Otorhinolaryngol Belg 1996;50: 183-9.

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

(13.) Rodgers GK, Chan KH, Dahl RE. Antral choanal polyp presenting as obstructive sleep apnea syndrome. Arch Otolaryngol Head Neck Surg 1991;117:914-16.

(14.) Salib RJ, Sadek SA, Dutt SN, Pearman K. Antrochoanal polyp presenting with obstructive sleep apnea and cachexia, Int J Pediatr Otorhinolaryngol 2000;54:163-6.

James R. Tysome, MA, MRCS; Hesham A. Saleh, FRCS (ORL-HNS)

From the Department of Otorhinolaryngology, Charing Cross Hospital, London.

Reprint requests: James Tysome, MA, 33 Burney St., London SE10 8EX, UK. Phone: [phone]; fax: [phone]; e-mail: [e-mail]

Originally presented at the annual meeting of the British Rhinological Society; Crewe, U.K.; May 5, 2004.