Metastatic urothelial carcinoma of the urinary bladder in a Sumatran tiger (Panthera tigris sondaica)

A 15-year-old spayed female Sumatran tiger (Panthera tigris sondaica) was presented with a short history of haematuria and dysuria, non-responsive to antibiotics, and a gradual decline to inappetence over a period of 2-3 months. Ultrasound examination showed a thickened urinary bladder wall and the renal pelvis of right kidney was dilated and cystic. A presumptive diagnosis of renal failure was made, and the tigress was euthanised due to deteriorating quality of life and pronounced weight loss. Histopathology revealed extensive erosion of the urinary bladder wall and marked congestion of the submucosal vasculature, a potential cause of the haematuria observed clinically. Numerous foci of neoplastic cells were also observed throughout the lung parenchyma as well as within lymphatic vessels of the lung, the liver and the kidney. A diagnosis of a metastatic non-papillary high-grade urothelial carcinoma (UC) of the urinary bladder was made. Consistent with this diagnosis, immunohistochemistry revealed the neoplastic cells were negative for uroplakin III, as has been reported for a subset of high-grade, infiltrative urinary bladder UCs of canines and humans. This is the first report of a primary tumour of the urinary bladder in a tiger and the first report of UC in a tiger.

Immunohistochemical Expression of Cyclin D1, Cytokeratin 20, and Uroplakin III in Proliferative Urinary Bladder Lesions Induced by o-Nitroanisole in Fischer 344/N Rats

o-Nitroanisole is an intermediate in the manufacture of azo dyes. In a National Toxicology Program stop-exposure study,o-nitroanisole induced hyperplasia, papillomas, and papillary carcinomas in the urinary bladder of Fischer 344/N rats.o-Nitroanisole was investigated since occupational or environmental exposure to aniline and azo dyes is a risk factor for urinary bladder cancer in humans. The current study describes the morphology of urinary bladder neoplasms seen in rats with respect to those observed in humans. This study also evaluated immunohistochemical expression of the cell cycle-related proteins cyclin D1 and p53 and the differentiation markers cytokeratin 20 and uroplakin III in hyperplastic (n= 11) and neoplastic (n= 6 papillomas,n= 11 carcinomas) lesions of the urinary bladder epithelium from rats treated with o-nitroanisole and in normal (n= 6) urinary bladders from untreated rats. The tumors observed were more similar to the papillary type rather than the muscle-invasive type of urinary bladder cancer in humans. The preneoplastic and neoplastic lesions observed suggest progression from hyperplasia to papilloma to papillary carcinoma. With neoplastic progression (hyperplasia to papilloma to carcinoma), cyclin D1 immunoreactivity progressively increased in intensity, percentage of cells staining, and distribution. Overexpression of p53 was not found. Cytokeratin 20 staining decreased in superficial cells, while uroplakin III staining increased in intermediate and basal cells with progression from hyperplasia to carcinoma. The results are consistent with increased cell cycle dysregulation or proliferation (cyclin D1), decreased differentiation (cytokeratin 20), and abnormal differentiation (uroplakin III) as lesions progress toward malignancy.