Nasopharyngeal sialocoele with underlying auditory tube neoplasia in a cat

CASE SUMMARY: An 8-year-old cat was presented with recent signs related to upper airway obstruction. CT revealed a hypoattenuating mass, with rim enhancement, in the nasopharynx. Paracentesis yielded a viscous fluid, consistent with saliva on cytology. The sialocoele was aspirated, and surgical excision of the ipsilateral mandibular and sublingual salivary glands was performed. The sialocoele recurred 3 months later, associated with a polypoid structure in the auditory tube region. This was surgically extirpated. Histology was consistent with a tubulopapillar adenocarcinoma. RELEVANCE AND NOVEL INFORMATION: To our knowledge, this is the first case report of a nasopharyngeal sialocoele with confirmed underlying neoplasia in a cat, and the first description of CT imaging features of a nasopharyngeal sialocoele in a cat.