+ General Considerations

  • Renal pelvis TCC are pedunculated, multilobulated, and locally aggressive
  • Metastatic rate of renal pelvic TCC is lower than renal carcinoma in dogs, but higher in cats
  • Renal pelvic tumors may be associated with struvite calculi because of urothelial irritation by renal calculi resulting in squamous metaplasia and malignant transformation of the urothelium
  • Prognostic factors in humans include multifocality, tumor grade and stage, DNA ploidy, and history of bladder TCC



  • Clinical signs are non-specific such as abdominal enlargement and abdominal pain
  • Urinary signs are uncommon
  • Lameness caused by either skeletal metastases or hypertrophic osteopathy

+ Urinalysis and Urine Sediment Cytology

  • Proteinuria is a common finding with renal tumors
  • Hematuria is uncommon with renal carcinoma, but can be seen with HSA, hemangioma, and renal pelvis TCC
  • Urine sediment cytology is rarely diagnostic for renal tumors

+ 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
  • Polycythemia is a reported paraneoplastic syndrome with renal tumors
  • Uremia may result from obstruction of urinary outflow, bilateral renal tumors, or age-related renal failure


+ General Considerations

  • Survey abdominal and thoracic radiographs, contrast radiography, ultrasonography, CT, and MRI are imaging modalities used to identify the presence and extent of renal tumors

+ Survey Abdominal Radiography

  • Survey abdominal radiographic findings: sublumbar lymph node enlargement, renomegaly, and skeletal metastases, especially lumbar vertebrae and pelvis
  • Abdominal mass is identified in 81% and localized to the kidney in 54% of dogs with primary renal tumors
  • Focal mineralization can be observed but difficult to differentiate tumor from renal calculi and GI opacities

+ Excretory Urography

  • Excretory urographic findings: space occupying renal mass, variable opacification of the renal parenchyma, and distortion of the renal pelvis
  • Excretory urography successfully identifies a renal mass in 96% dogs with primary renal tumors

+ Ultrasonography

  • Ultrasonography results in earlier diagnosis and more successful treatment of renal neoplasia in humans
  • Renal tumors, except for LSA, produce a mixed echogenicity with disruption of the normal renal architecture
  • Renal LSA is usually hypoechoic
  • Ultrasonography is also useful in detecting neoplastic involvement of regional lymph nodes and adjacent structures such as the adrenal glands ± caudal vena cava

+ Advanced Imaging

  • CT scans are used for the diagnosis and local staging of renal neoplasia with a high correlation between CT findings and gross pathology
  • MRI is preferred for identifying adjacent vascular and visceral invasion, especially if renal-sparing surgery is planned
  • Other imaging techniques include caval venography and nuclear scintigraphy

+ Biopsy

  • Biopsy is required for definitive diagnosis of renal tumors
  • Biopsy techniques: FNA, needle biopsy, and wedge biopsy
  • FNA and needle-core biopsy can be performed using a blind, ultrasound-guided, laparoscopic, or open technique
  • Ultrasound-guided biopsy is a rapid, safe, and accurate technique for diagnosing focal and diffuse renal disease
  • Blind percutaneous needle biopsy can be performed in cats where the kidney can be immobilized by palpation
  • Percutaneous biopsy should be performed with bilateral renal lesions or suspected renal LSA
  • Single procedure surgical biopsy, staging, and definitive treatment preferred for unilateral lesions
  • Complications of needle biopsy: minor localized hemorrhage, microscopic hematuria, and tumor seeding


+ Surgery

  • Surgical management depends on behaviour of the tumor, presence of metastases and bilateral renal involvement, and invasion of the caudal vena cava and adjacent structures
  • Nephroureterectomy is recommended for unilateral disease

+ Chemotherapy

  • Non-steroidal anti-inflammatory drugs, such as piroxicam, meloxicam, and deracoxib, may have anticancer effects
  • Chemotherapy drugs with known efficacy against TCC include cisplatin, carboplatin, doxorubicin, and mitoxantrone



T0 No evidence of neoplasia
T1 Small tumor without deformation of the kidney - Primary Tumor
T2 Single tumor with deformation ± enlargement of the kidney
T3 Tumor invading perinephric structures ± pelvis or ureter ± renal blood vessels
T4 Tumor invading adjacent organs
M0 No evidence of metastasis
M1 Evidence of distant metastasis with site specified with (a) single metastasis, (b) multiple metastasis in 1 organ, and (c) multiple metastasis in ≥ 2 organs - Metastasis
N0 No evidence of regional lymph node involvement
N1 Ipsilateral regional lymph node involvement - Node
N2 Bilateral regional lymph node involvement
N3 Distant lymph node involvement