Atypical manifestations of feline inflammatory polyps in three cats

Abstract

Inflammatory polyps of the feline middle ear and nasopharynx are non-neoplastic masses that are presumed to originate from the epithelial lining of the tympanic bulla or Eustachian tube. The exact origin and cause are unknown, however, it is thought that inflammatory polyps arise as a result of a prolonged inflammatory process. It is unclear whether this inflammation initiates or potentiates the development and growth of inflammatory polyps. Cats with inflammatory polyps typically present with either signs of otitis externa and otitis media or with signs consistent with upper airway obstruction. Traditional diagnostics involve imaging of the tympanic bulla either with skull radiographs or computed topography (CT). Treatment consists of traction and avulsion of the polyp with or without ventral bulla osteotomy (VBO) to remove the epithelial lining of the tympanic bulla. The three cases described here are unusual manifestations or presentations of feline inflammatory polyps that address the following issues: (1) concurrent otic and nasopharyngeal polyps, (2) potential association with chronic viral infection, (3) polyp development in the contralateral middle ear, (4) CT appearance of the skull following VBO, and (5) development of secondary pulmonary hypertension.

Fig 1

(A) Transverse CT image at the level of the tympanic bulla demonstrating soft tissue density within the left bulla and extending into the horizontal ear canal. (B) Transverse CT image at the level of the nasopharynx demonstrating a soft tissue intensity mass protruding into the left nasopharyngeal area.

Fig 2

(A) Transverse CT image at the level of the tympanic bulla. Soft tissue opacity completely fills the right tympanic bulla and the wall is thickened. The left tympanic bulla is normal. (B) Transverse CT image at the level of the tympanic bulla. There is an increased soft tissue opacity within the left tympanic bulla and a soft tissue opacity within the ostectomized right tympanic bulla.

Fig 3

(A, B) Lateral and ventrodorsal thoracic radiographs demonstrating cardiomegaly, megaesophagus, peribronchial and interstitial lung lobe pattern, and enlarged and tortuous pulmonary arteries in the caudal lung lobes. (C) Lateral thoracic radiograph showing findings consistent with moderate to severe pleural effusion.