Comparison of CT features of 79 cats with intranasal mass lesions

OBJECTIVES: This retrospective multicentre study compared the CT characteristics of cats diagnosed with intranasal mass lesions to determine if defining imaging features exist between different tumour types and between neoplastic and non-neoplastic lesions. METHODS: The medical records of two institutions were reviewed for cats with CT findings consistent with an intranasal mass lesion with subsequent histopathological examination. For each CT scan the mass location, growth pattern, margin distinction, contrast enhancement pattern and presence of intralesional areas of mineralisation or necrosis were recorded. The presence of facial deformity, the location and type of bone changes, extranasal extension of the mass lesion and the regional lymph nodes size, contrast pattern and hilus visibility were also documented. RESULTS: Thirty-five cats with nasal lymphoma, 28 cats with non-lymphomatous nasal neoplasia (carcinoma or sarcoma) and 16 cats with inflammatory lesions met the inclusion criteria. Cats with non-lymphomatous nasal neoplasia were more likely to show unilateral nasal changes (odds ratio [OR] 3.9), areas of intralesional calcification (OR infinity) and extension of the mass lesion within the frontal sinus (OR 4.5), while cats suffering from nasal lymphoma were more likely to show a mixed (OR 4.5) and expansile growth pattern (OR 7.8), and a regional lymphadenomegaly (OR 2.4). The CT findings in cats diagnosed with inflammatory mass-like lesions were highly variable and overlapped with findings for nasal neoplasms but were significantly associated with the absence of bony changes to the nasal cavity boundaries (OR 10.2). CONCLUSIONS AND RELEVANCE: Findings from the current study support the ability of CT to aid in the discrimination of tumour type in cats presented with an intranasal mass lesion.