Comparison of Computed Tomographic Features of Confirmed Nasal Neoplasia in Dogs.

While computed tomography (CT) imaging is commonly used to evaluate canine nasal tumors, the ability to differentiate tumor types based on imaging features remains limited. This retrospective study examined dogs with confirmed nasal neoplasia to determine whether CT characteristics differ between epithelial and mesenchymal tumors. Cases from a single institution (2013-2022) were reviewed, and the frequency of CT features between epithelial and mesenchymal tumors was compared using Fisher's exact test. Also, CT features of less commonly reported nasal neoplasms, including squamous cell carcinomas, polyps, and osteosarcomas, were described. Sixty-seven dogs with nasal neoplasia were identified; 48 (72%) had a type of epithelial neoplasia, and 19 (28%) had mesenchymal neoplasia. Dogs with epithelial neoplasia were more likely to show intracranial mass extension (p = 0.04; OR 5.1; 95% CI 1.1-23.9), cribriform plate lysis (p = 0.03; OR 4.5; 95% CI 1.2-15.8), lysis of ipsilateral sphenoid sinus (p < 0.0001; OR 18.7; 95% CI 3.9-85.9), mass extension into ipsilateral sphenoid sinus (p = 0.01; OR 5.8; 95% CI 1.6-20.2), and frontal sinus fluid (p = 0.05; OR 4.7; 95% CI 1.3-16.2) than dogs with mesenchymal neoplasia. Dogs with mesenchymal neoplasia were more likely to show fluid in the ipsilateral maxillary recess (p = 0.01; OR 5.3; 95% CI 1.4-18.6). Squamous cell carcinoma patients had two distinct presentation patterns: either a small nodule centered on the nasal planum with no associated lysis and mass extension, or a mass centered on and causing lysis of the maxillary or nasal bone. This investigation provides the first comprehensive comparison of CT characteristics between different canine nasal tumor types, offering potential prebiopsy diagnostic indicators.