Polyp

Nasopharyngeal polyps are benign, soft, inflammatory growths that arise in the nasal cavity, nasopharynx (the area above the soft palate), middle ear, and/or external ear canal. They are seen most commonly in cats and less often in dogs. In dogs, these polyps tend to extend into the ear canal rather than into the back of the throat.

The exact cause is unknown. They typically occur in young cats, and multiple kittens from the same litter may be affected. Chronic inflammation, possibly triggered by respiratory viruses, is suspected, although no specific infectious agent has been consistently identified. While bacterial infections often coexist, antibiotics alone do not resolve the condition.

Most polyps originate from the lining of the middle ear (tympanic cavity). They are usually attached by a stalk and may reach up to 2 cm in diameter. As they enlarge, they may rupture through the eardrum into the external ear canal or extend through the Eustachian tube into the nasopharynx. In a small percentage of cases, growth occurs in both directions. Polyps are usually unilateral, although 13–24% of cats may develop bilateral disease.

Clinical signs depend on polyp location.

Nasopharyngeal polyps typically cause upper airway obstruction and secondary infections, with signs such as:

• sneezing
• noisy or labored breathing
• difficulty eating or swallowing
• nasal discharge
• changes in vocalization

Polyps involving the middle or external ear commonly cause ear disease, including:

• head shaking
• ear discharge
• scratching or pawing at the ear
• abnormal eye movements (nystagmus)
• head tilt
• loss of balance (ataxia)
• changes in the eye on the affected side consistent with Horner’s syndrome

Nasopharyngeal polyps may be visualized or palpated beneath the soft palate. Large polyps can push the soft palate downward. Flexible endoscopy with retroflexion allows direct visualization of the nasopharynx, while otoscopic examination is used to detect extension into the external ear canal. When confined to the middle ear, the tympanic membrane may appear distorted or discolored.

If the diagnosis is uncertain, skull radiographs may reveal soft tissue changes in the middle ear. More commonly, CT or MRI is recommended, as these modalities provide superior information about polyp size, origin, and extent.

Preoperative biopsy is generally avoided, especially when the polyp causes airway or swallowing obstruction. Histopathologic examination of the removed mass is recommended to confirm its benign nature.

Polyps in the nasopharynx or external ear canal can often be removed by gentle traction under general anesthesia. Complete removal of the stalk reduces the risk of recurrence.

However, traction alone frequently fails to eliminate the polyp base, leading to regrowth. For this reason, many patients undergo a ventral bulla osteotomy, a surgical approach that opens the middle ear to allow complete removal of the polyp origin. Referral to an ACVS board-certified veterinary surgeon is often recommended for this procedure.

Most cats recover quickly and require minimal postoperative care.

Temporary postoperative complications are common, particularly after ventral bulla osteotomy, and may include:

• Horner’s syndrome
• balance disturbances
• head tilt

Important nerves controlling eye function pass along the inner wall of the middle ear and are frequently affected during surgery. As a result, up to 80% of cats develop Horner’s syndrome, characterized by elevation of the third eyelid, constricted pupil, and drooping of the upper eyelid. This condition is usually temporary and does not impair vision or behavior.

Because the inner ear structures are nearby, some cats may also experience temporary vestibular signs such as wobbliness, head tilt, and nystagmus. Careful removal of the bulla lining is essential to prevent recurrence while minimizing neurologic damage.

Home Care

• Pain medication is typically prescribed after ventral bulla osteotomy
• Antibiotics may be used if infection is suspected
• Corticosteroids may be considered after traction-only removal to reduce recurrence
• An Elizabethan or soft recovery collar may be recommended
• Soft or wet food may be advised during healing
• If appetite does not return promptly, veterinary reassessment is required

Prognosis

Overall prognosis is excellent. Even cats that develop Horner’s syndrome or balance problems usually recover within weeks to one month.
Recurrence rates are significantly lower when traction is combined with ventral bulla osteotomy (<2–10%), compared with traction alone (30–50%).