Veterinary Society of
Surgical Oncology

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
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