Polyps removed surgically from a cat are adjacent to a cotton swab for size comparison. Photo courtesy of VIN.
Naso-pharyngeal polyps (nasopharyngeal polyps, otopharyngeal polyps, inflammatory polyps, middle ear polyps) are the most common masses that are seen in the external ear canal in cats. They are benign growths that can be seen in the back of the cat’s throat, the middle ear, and above the soft palate. Typically, these polyps are seen in younger cats, although cats of any age can get them. There is no known breed or sex predilection.
No one is quite certain what causes nasopharyngeal polyps. They may be caused by inflammation or a virus. Some cats with these polyps also have feline calicivirus, and some cats have ear infections. Both of these problems can cause inflammation.
Signs
How an individual cat is affected depends on the location and size of the growth. Signs may include:
- snoring,
- nasal discharge,
- sneezing,
- difficulty breathing,
- head shaking,
- balance problems,
- ear scratching,
- head tilting,
- nystagmus (an involuntary movement of both eyes in the same direction),
- foul odor from the ear or,
- an ear infection.
If the polyp is large, the cat may have trouble swallowing, causing the owner to think the cat is not hungry. There have been two published reports of megaesophagus (dilated esophagus) secondary to chronic nasopharyngeal obstruction from a polyp, one published report of hiatal hernia secondary to the chronic nasopharyngeal obstruction, and one published report of intracranial abscess from the chronic otitis media/interna related to the polyp, but those secondary problems appear to be extremely rare.
Diagnosis
Diagnostic tests include a physical examination, imaging (radiographs/CT/MRI) of the skull, and biopsy of the growth. If the ear is painful, cats may require sedation or anesthesia for the ear canal examination. If the cat is going to be sedated or anesthetized, that’s a perfect time to take radiographs of the skull. A biopsy may be necessary for a definitive diagnosis.
Treatment
Polyps have to be removed surgically. Some polyps located at the back of the throat can be plucked out. This is a traction/avulsion technique. However, plucked growths often regrow. In some cases, a ventral bulla osteotomy may be used on ear polyps instead of the traction/avulsion technique. An e-collar may be necessary for 10 to 14 days after surgery to prevent the cat from disturbing the site. After surgery, the cat may be on antibiotics for a few weeks.
Depending on the location of the polyp, the surgery (and the polyp) may cause some side effects on the nerves around the eye. The cat may have difficulty blinking. Generally, the nerve damage will not last more than a few days or weeks, although permanent damage is possible.
Because the exact cause of each polyp is unknown, polyps sometimes recur after surgery. Some studies have shown that there is a recurrence rate of 15-50% after traction removal. Your veterinarian may advise the use of prednisone for two weeks after traction removal because it may reduce the incidence of recurrence. As with all diseases, the earlier a nasopharyngeal polyp is diagnosed and treated, the better the prognosis.