A Retrospective Case Series of Bladder Carcinoma in Dogs from the Federal University of Uberlândia Veterinary Hospital (2015-2025)

Abstract

The objective of this retrospective study was to evaluate the clinical and epidemiological characteristics, as well as the anatomopathological aspects, of dogs affected by urothelial carcinoma of the urinary bladder, diagnosed by cytopathology and histopathology at the Animal Pathology Laboratory of the Veterinary Hospital of the Federal University of Uberlândia (HOVET–UFU) between 2015 and 2025. A total of 24 dogs were evaluated, predominantly geriatric, with a mean age of 9.8 years, a predominance of females (61%), and mostly mixed-breed animals. The most prevalent clinical signs were hematuria (52%), dysuria (23%), and polyuria (19%). In laboratory tests, 33% of the animals presented anemia and 46% azotemia. In urinalysis, occult blood was present in 100% of the dogs, bacteriuria in 90%, and an increased number of transitional cells in 80% of the cases. On ultrasound examination, 88% of the dogs showed alterations compatible with neoplasia, with lesions predominantly located in the bladder trigone (33%). In cytology (n=10), high cellularity, marked pleomorphism, multinucleated cells, and Melamed-Wolinska bodies were observed. In histopathology (n=14), the predominant pattern was papillary, observed in 71% of cases, whereas the solid pattern corresponded to 29%. Cellular pleomorphism was marked (71%), 64% of diagnoses showed karyomegaly, and 92% exhibited coarse or reticulated chromatin. The mean mitotic index was 13.29/2.37 mm², and lymphatic/vascular invasion was observed in 7% of the animals. Most tumors (78%) were classified as high grade, reinforcing the aggressive behavior of this neoplasm