Ultrasonographic features of feline renal neoplasia: a retrospective study on 187 cases

Abstract

Objectives: Ultrasonography plays a crucial role in diagnosing feline renal diseases, including neoplasia. The aims of this study were to describe ultrasonographic features of renal neoplasia in cats and to investigate potential differences between tumor types. Methods: In this multicenter retrospective study, ultrasonographic images of feline kidneys with cytologically/histologically confirmed renal neoplasia were reviewed. For each kidney, ultrasonographic characteristics (renal length, presence and appearance of a mass, nodules, hypoechoic subcapsular rim, pelvic distension, retroperitoneal effusion) were recorded and compared for each tumor type. Results: A total of 187 cats (373 kidneys) were included. Tumor types were lymphoma (n = 118, 63%), carcinoma (n = 53, 28.5%), sarcoma (n = 10, 5%), adenoma (n = 3, 2%), histiocytic sarcoma (n = 2, 1%) and nephroblastoma (n = 1, 0.5%). Bilateral disease (P <0.001) and other organ involvement (P = 0.026) were more frequent in lymphoma. A single mass was more frequent in carcinoma (P <0.001). Masses were more frequently hypoechoic in lymphoma (81%) and sarcoma (86%) than in carcinoma (40%) (P = 0.001). In kidneys with masses, a hypoechoic subcapsular rim was more frequent in lymphoma (P = 0.004). In kidneys without mass lesions, kidneys with lymphoma (mean size 51.3 ± 9.8 mm) were significantly larger (P = 0.02) than those with carcinoma (mean size 46.1 ± 6.4 mm) and sarcoma (mean size 42.8 ± 8.9 mm). Conclusions and relevance: Lymphoma was the most common renal neoplasia, followed by carcinoma. Some ultrasonographic features, including bilateral involvement, single masses, multiple nodules, hypoechoic subcapsular rim and severity of nephromegaly, can help differentiate feline renal tumor types.