Transitional cell carcinoma in the domestic cat

In 17 cases of transitional cell carcinoma in cats the most common site for primary neoplasia was the urinary bladder; metastasis was recorded in five of the cases. Nine of the cases have been reported previously; the eight additional carcinomas from the files of the New York State College of Veterinary Medicine were highly invasive and had a desmoplastic response. According to WHO guidelines they were classified as nonpapillary, infiltrating; papillary, infiltrating; and variants of transitional cell carcinoma.