ABSTRACT
The urinary system includes the kidneys, ureters, urinary bladder, and urethra. Sediment examination is one part of a complete urinalysis, which also includes gross examination, specific gravity measurement, and dipstick analysis. Transitional cell carcinomas (TCC) of the kidney are morphologically similar to those described later for the urinary bladder. TCC is the most common neoplasm to affect the urinary bladder in both dogs and cats, but it is a rare diagnosis in cats. In dogs, TCC most commonly affects the trigone region. Samples from TCCs, particularly squash preparations from traumatic catheterizations, will be moderately to highly cellular with transitional cells in small clusters and large sheets. Differentiating polypoid cystitis from TCC in dogs can be a difficult process; many of the presenting signs are similar and there is cytologic overlap between the two conditions. A few bilirubin crystals may be found in concentrated urine of normal dogs.
