PATHOPHYSIOLOGY

General Considerations

•epithelial tumors, in particular TCC, are the most common tumors of the urinary bladder and account for up to 92% of feline bladder tumors

•other urinary bladder tumors include SCC, ADC, rhabdomyosarcoma, FSA, CSA, leiomyosarcoma, HSA, chemodectoma, and benign tumors such as leiomyoma and fibroma

Transitional Cell Carcinoma

General Considerations

•dogs excrete large quantities of tryptophan metabolites in the urine

•however, cats metabolize tryptophan differently and do not excrete urinary tryptophan metabolites

Location

•TCC are either diffuse or located in the fundus or ventral bladder wall in cats

•TCC are most frequently located in the trigonal area in dogs resulting in urinary tract obstruction

DIAGNOSIS

Clinical Signs

•dysuria, hematuria, pollakiuria, and stranguria

•vaginal discharge

•urinary obstruction

•incontinence

Urinalysis and Urine Sediment Cytology

General Considerations

•hematuria and proteinuria are consistent findings on urinalysis due to ulceration of the urothelial mucosa

•bacteruria, pyuria, and positive urine cultures are common in cats

•bladder wash cytology may improve diagnosis capabilities by reducing contaminants

Urine Sediment Cytology

•neoplastic transitional cells are difficult to differentiate from reactive transitional cells

•mesenchymal tumors exfoliate poorly and are rarely diagnosed with analysis of urine sediment

Blood Tests

•hematology and serum biochemistry findings are usually normal or non-specific

•mild to moderate normochromic, normocytic anemia can be caused by either hematuria or bone marrow suppression secondary to chronic disease

•uremia may result from neoplastic obstruction of urinary outflow or age-related renal failure

Imaging Studies

Survey Radiographs

•imagining techniques include survey abdominal and thoracic radiographs, contrast radiography, and CT

•survey radiographs: sublumbar lymph node enlargement, renomegaly, and metastatic disease in the pulmonary parenchyma or skeleton, particularly lumbar vertebrae and pelvis

•positive contrast cystography is useful for identification of mucosal abnormalities and space occupying lesions

•excretory urogram is indicated to determine the location and extent of obstructive urinary tract disease when the urethra cannot be catheterized

Ultrasonography

•ultrasonography is recommended to determine the location and extent of bladder involvement, regional lymph node size and appearance, and involvement of adjacent anatomical structures such as the colon

•ultrasonography is superior to excretory urography and double-contrast cystography in detecting TCC

Biopsy

•biopsy is required for definitive diagnosis of urinary tract tumors

•biopsy techniques include FNA, needle biopsy, catheter biopsy, cystoscopic, and open surgery

•percutaneous biopsy procedures are not recommended due to the risk of tumor seeding

•inflammation secondary to necrosis and ulceration is common and may result in false-negative findings

TREATMENT

Surgery

•surgical techniques for management of bladder tumors include:

•palliative procedures: tube cystostomy ± partial cystectomy

•curative-intent procedures: partial cystectomy and total cystectomy with urinary diversion

•cystostomy tube can be placed percutaneously or with either laparoscopic or open surgery

•complications: stranguria, pollakiuria, hematuria, urine leakage around the stoma, and vesicoureteral reflux which predisposes to ascending UTI and tumor seeding of the upper urinary tract

Adjunctive Management

•role of chemotherapy and radiation therapy is unknown