Transitional Cell Carcinoma

Also know as: TCC

Introduction

Transitional epithelium, also known as urothelium is found in the urinary bladder, ureters and in the superior urethra and prostate ducts.

Transitional cell carcinomas arise from this epithelium and are the most common form of canine urinary bladder tumour. They are more common in the older female.

Transitional cell carcinomas may be solitary or multiple papillary-like projections from the mucosa or may develop as a diffuse infiltration of the ureter, bladder, prostate, and/or urethra. They are highly invasive and metastasize frequently, most commonly to the regional lymph nodes and lungs, but also to the long bones and pelvis. Ureteral and bladder neoplasms can cause chronic obstruction to urine flow with secondary hydronephrosis. Urethral tumors are more likely to cause acute obstructive uropathy. Intractable secondary bacterial urinary tract infections are commonly associated with neoplasms of the bladder and urethra.

The aetiology is largely unknown, but cyclophosphamide administration has been identified as one of the causes.

Shetland sheepdogs, West Highland White Terriers and Beagles appear to be predisposed.

TCC are also found in cats, where males appear to be predisposed.

Clinical signs

The most common clinical signs are: haematuria, dysuria, stranguria and pollakiuria.

Animals with ureteral obstruction and hydronephrosis may show unilateral abdominal pain and have en enlarged kidney.

Signs of uraemia may be apparent if there is urethral obstruction or bilateral ureteral obstruction.

Rectal palpation may reveal a thickened, cord-like urethra or urethral masses.

Diagnosis

The history and clinical signs will be highly indicative of a lower urinary tract disease.

Urinalysis and culture should be performed to rule out or identify a urinary tract infection. It may reveal a bacterial infection, or haematuria. Neoplastic cells may be found in the sediment. These will be of epithelial origin with criteria suggesting malignancy.

It may be hard to distinguish neoplastic cells from reactive epithelial cells associated with inflammation.

Contrast radiography is also helpful in making a diagnosis. Techniques such as a double-contrast cystogram may reveal the mass in the bladder. A retrograde vagino-urethrogram may also reveal a mass. The bladder tumour is often found at the trigone.

Ultrasonography may help identify the mass and evaluate the regional lymph nodes and other organs for distant spread.

Biopsy of the tumour is required for definitive diagnosis. Tissue can be obtained by cystotomy, cystoscopy and traumatic catheterisation.

Staging is completed with ultrasonography and thoracic radiography.

An antigen test exists which can be performed on urine and which detects antibodies generated in response to bladder tumour antigens. The test has a 90% sensitivity, but it can be falsified by haematuria and proteinuria.

Treatment

As the bladder trigone and the urethra are commonly involved, complete surgical resection of the tumour is often not possible. Also, the tumour is often multifocal and may involve most of the bladder lining.

Surgical techniques may involve: partial bladder removal, permanent urinary catheter, urethral stenting, ureterocolonic anastomosis, laser ablation combined with chemotherapy.

Chemotherapy with cisplatin or piroxicam may prolong survival.

Antibiotics may have to be used to treat the secondary bacterial infections which commonly occur.

Prognosis is often poor as, even when resected, these tumours recur and metastasise rapidly.

References

Merck and Co (2008) Merck Veterinary Manual Merial

Withrow, S. (2001) Small animal clinical oncology Elsevier Health Sciences

Meuten, D. (2002) Tumors of domestic animals Wiley-Blackwell