[Transitional cell carcinoma of the urinary bladder of a dog]

The occurrence of a urinary bladder transitional cell carcinoma in a dog is reported. The spontaneous occurrence of such tumours is rare in dogs and in this case no aetiological or predisposing factors for the development of this tumour could be determined. Histologically, the tumour was classified as a papillary, invasive transitional cell carcinoma.