Diagnosing transitional cell carcinoma can be a difficult clinical challenge. Clinical signs (pollakiuria, dysuria, stranguria,
and hematuria) are nonspecific, and differential diagnoses include granulomatous cystitis, other neoplastic diseases (lymphoma,
rhabdomyosarcoma), a persistent or recurrent urinary tract infection, and urinary calculi—the latter two of which may occur
concurrently with transitional cell carcinoma.
A urinalysis may reveal abnormal epithelial cells, but in the face of inflammation, transitional cells may be reactive, and
distinguishing reactive cells from neoplastic cells can be difficult, even for an experienced clinical pathologist. While
many clinicians use the veterinary bladder tumor antigen (V-BTA—Polymedco) urine test to confirm transitional cell carcinoma,
false positive results may occur when pyuria (> 30 WBC/HPF), hematuria (> 30 RBC/HPF), proteinuria (4+), or glucosuria (4+)
is present. Since this test has an overall sensitivity of 90% and an overall specificity of 78% for diagnosing transitional
cell carcinoma, it may be more useful in routine screenings of at-risk populations (e.g. Scottish terriers, West Highland white terriers, Shetland sheepdogs, beagles, geriatric patients) in the absence of urinary
An ultrasonographic examination of the urinary tract may reveal a mass in the trigone or adjacent urethra, providing suggestive,
but not definitive, evidence of transitional cell carcinoma.
Although somewhat controversial, I do not perform ultrasound-guided fine-needle aspiration biopsy in patients with suspected
transitional cell carcinoma because of concerns about seeding the needle tract with neoplastic cells. Transitional cell carcinoma
is thought to be easily transplantable, so samples should be obtained by way of the urinary tract. I prefer to use either
traumatic catheterization or cystoscopy-guided biopsy to obtain diagnostic samples. While samples obtained via cystoscopy
are small, there is a classic gross appearance (friable, white fimbriated tissue), which can provide further indirect support
for the histologic diagnosis.
Linda Fineman, DVM, DACVIM (oncology)
Veterinary Medical Specialists
907 Dell Avenue Campbell, CA 95008