Spontaneous resolution of a suspected nasopharyngeal polyp in a young cat

Abstract

Objective

To detail a case of a suspected inflammatory nasopharyngeal polyp, in a young cat, that disappeared without medical or surgical therapy.

Animal

A 5-month-old neutered male domestic shorthair cat that was client-owned and indoor-only.

Procedure

Serial head computed tomographic scans were done on a young cat to diagnose and monitor the size and location of the suspected inflammatory nasopharyngeal polyp.

Results

At 145 d after diagnosis of a suspected inflammatory nasopharyngeal polyp in a young cat via head computed tomographic scan, the mass was no longer present. The cat had not undergone any surgical or medical therapy from Day 0 to Day 145.

Conclusion

Although the standard of care for nasopharyngeal polyps in cats is to conduct the appropriate diagnostics and surgical treatment, this case may provide an alternative management approach if surgical treatment is not feasible or euthanasia is being considered.

Clinical relevance

This article presents a case in which a nasopharyngeal mass, a suspected inflammatory polyp, in a young cat spontaneously resolved with no medical or surgical intervention.

A 5-month-old, client-owned, indoor-only, neutered male domestic shorthair cat was presented with an intermittent right-sided head tilt, stertorous breathing, lethargy, and increased respiratory effort. The cat had not responded to recent antibiotic therapy. Results of a chest radiograph were within normal limits. Physical examination revealed normal thoracic auscultation. Results from oral examination, abdominal palpation, and rectal temperature check were normal. Due to the young age of the cat and the presenting clinical signs, a nasopharyngeal polyp was suspected.

A computed tomographic (CT) scan of the head was obtained and reviewed by a Board-certified veterinary radiologist (author RO). The radiologic diagnosis confirmed the presence of a nasopharyngeal mass, likely an inflammatory polyp, along with right-sided obstructive otitis media and reactive local lymphadenopathy (Figure 1). A right-sided luminal mass (likely a polyp) in the tympanic bulla could not be ruled out. The radiologist’s recommendation was to surgically remove the nasopharyngeal mass and submit it for histopathological examination. However, due to the small size of the cat, surgery was delayed and robenacoxib was dispensed for oral administration, q24h for 6 d.

FIGURE 1.

Initial computed tomographic scan (Day 1) of a young cat. Note the nasopharyngeal mass (arrow in A) with right-sided obstructive otitis media (arrow in B).

On Day 40, the cat was presented for a recheck and to discuss polyp removal. The client had chosen not to administer the robenacoxib prescribed at the previous visit, but the cat was much improved clinically. Another CT scan was done at that time (Figure S1, available online from: Supplementary Materials). The CT scan indicated that the nasopharyngeal polyp had decreased in size. The right-sided obstructive otitis media had resolved, and there was no longer any suspicion of a luminal mass being present in the right tympanic bulla. It was decided that another CT scan would be obtained after 1 mo, to determine the size of the nasopharyngeal mass.

At the next recheck on Day 82, another CT scan was done (Figure S2, available online from: Supplementary Materials). The radiology report indicated that the nasopharyngeal mass was significantly smaller and “resolving.” The right tympanic bulla continued to appear normal, except for slight thickening of the walls. The cat was still doing clinically well.

A final CT scan was done on Day 145 (Figure 2). The nasopharyngeal mass was absent. Therefore, the previously present nasopharyngeal mass, suspected to be an inflammatory polyp, was absent. The cat was clinically normal.

FIGURE 2.

Final follow-up computed tomographic scan (Day 145) of a young cat. The nasopharyngeal mass is no longer present (arrow in A). Tympanic bulla thickening has resolved (arrow in B).

Inflammatory polyps can occur in the oral cavity, nasal cavity, nasopharynx, Eustachian tube, and tympanic bulla (1). Typically, they are diagnosed in cats < 1 y of age that are exhibiting signs of stertorous breathing, gagging, dyspnea, dysphagia, head tilt, sneezing, and sometimes weight loss and unkempt hair coat (2). The etiology is unknown, but they may be congenital or may arise from chronic viral infection or from chronic inflammation (3).

Clinical signs, a thorough oral examination, and appropriate imaging are key in identifying the correct diagnosis (1). Surgical removal of any identified polyps is the ideal method of treatment; however, this can present challenges if a polyp is in a difficult location to access, if the animal is still very young and small (1), or if financial limitations prevent surgery. Recurrence of inflammatory polyps surgically removed has been documented infrequently (3). If surgical removal is not an option, some inflammatory polyps will respond to anti-inflammatory drugs, but recurrence is common (1). Although the case described in this article may be exceptional, an inflammatory polyp may resolve spontaneously in cases where surgery or anti-inflammatory drug administration are not options.

To our knowledge, there has not been another documented case of spontaneous resolution of an inflammatory nasopharyngeal polyp. Therefore, we felt it pertinent to document this exceptional case, so that others will consider the possibility that a nasopharyngeal inflammatory polyp could resolve in cases where surgical treatment is not an option or euthanasia is being considered. Further research is needed to better understand inflammatory nasopharyngeal polyp etiology, occurrence, and resolution.