Case report of a mass that mimicked an antrochoanal polyp.

From the Division of Otorhinolaryngology, Department of Surgery, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, SAR.

Reprint requests: Prof. Andrew van Hasselt, Division of Otorhinolaryngology, Department of Surgery, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, SAR. Phone: [phone]; fax: [phone]; e-mail: [e-mail]

Abstract

We describe the case of a patient who was originally diagnosed with an antrochoanal polyp. During avulsion of the mass by endoscopic polypectomy, it was discovered that the stalk of the polyp actually arose from the mucosa of the right superior turbinate rather than from the mucosa of the maxillary ant rum. A diagnosis of choanal polyp was made.

Case report

A 37-year-old Chinese man complained of bilateral nasal obstruction of 1 year's duration. The obstruction was more marked on expiration. There was no nasal discharge or history of bleeding.

Except for the bilateral nasal obstruction on expiration, an anterior rhinoscopic examination was unremarkable. Endoscopic examination of the postnasal space revealed a large, smooth, and pale pedunculated polypoid mass at the choana (figure 1). The mass filled the entire nasopharynx and protruded to the oropharynx (figure 2). The exact origin of the polyp could not be determined in the clinic because the middle meatus and sphenoethmoid recess were very narrow. The presumed diagnosis was a right antrochoanal polyp.

Computed tomography (CT) showed that the paranasal sinuses were normal. The isodense polyp was clearly visible on CT, filling up the nasopharynx and extending downward to the oropharynx; no intracranial communication was noted. However, the origin of the mass could not be determined. The patient underwent an examination of the postnasal space and an endoscopic polypectomy under general anesthesia. During the operation, the stalk of the polyp was found to arise from the mucosa of the right superior turbinate. The right hiatus semilunaris was normal. The stalk of the polyp was avulsed, and the entire polyp was delivered through the oropharynx. There was minimal bleeding from the avulsed stalk. The cut end of the polyp consisted of predominantly firm fibrous tissue.

Histologic examination of the polyp revealed loose fibrous tissue with central edematous stroma. Chronic inflammation was evident in the superficial respiratory epithelium. The patient was asymptomatic following the operation, and there was no sign of recurrence at the 2-year followup.

Discussion

The symptoms and physical findings in this patient mimicked an antrochoanal polyp, which originates in the mucosa of the maxillary antrum. Lopatin et al reviewed 20 consecutively presenting patients who had choanal polyps and classified each polyp as either antrochoanal, sphenochoanal, or ethmochoanal, depending on the site of origin. [1] Antrochoanal polyp is the most common of the three types. This case illustrates an uncommon presentation of a choanal polyp, as CT did not demonstrate any involvement of the paranasal sinuses. The diagnosis of inverted papilloma should also be considered in a patient whose polyp does not arise from the paranasal sinuses.

Reference

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