Urothelial Carcinoma in a Cat with Bilateral Ectopic Ureters.

A 10-year-old neutered female Maine Coon was presented with haematuria, weight loss, polyuria/polydipsia and progressive azotaemia. Diagnostic imaging revealed bilateral renal pelvic dilation, ureteral distension and ectopic ureters. Bacterial pyelonephritis was diagnosed, but the azotaemia progressed despite antibiotic therapy, and suspected ureteral obstruction prompted surgical ureteral reimplantation. The visualisation of omental nodules and thickening of the ectopic right ureterovesicular junction intraoperatively raised suspicion of malignancy, and histopathology revealed urothelial carcinoma with carcinomatosis. The cat was euthanised postoperatively due to clinical deterioration, characterised by persistent oliguria and progressive azotemia. Clinicians should consider malignancy as a differential in cats with ectopic ureters and an atypical or refractory clinical course.