kidney neoplasm

Etiology

• Malignant tumors
  • renal cell carcinoma
  • squamous cell carcinoma of the collecting system
  • transitional cell carcinoma of the renal pelvis or collecting system
  • metastatic tumor from another primary site
    • breast, lung, adrenal
  • fibrosarcoma
  • lymphoma
  • nephroblastoma
• Benign masses
  • renal calculi/nephrolithiasis [kidney stones]
  • acute focal bacterial nephritis
  • renal tuberculosis
  • infrarenal hematoma
  • multi-locular renal cyst
  • angiomyolipoma
  • oncocytoma
  • renal adenoma

Pathology

• the only reliable way to rule out renal cell carcinoma is to remove the entire lesion surgically & examine the complete specimen
• biopsy of renal mass is of little, if any, role in ruling out renal cell carcinoma

Clinical manifestations

• symptoms
  • flank pain (40-50%)
  • blood-tinged urine - most common presenting complaint
  • report of palpable mass in flank
  • night sweats
  • bone pain (suggests metastasis)
  • fatigue
  • unintentional weight loss
• signs
  • hematuria (gross or microscopic)
  • fever of undetermined origin (FUO)
  • left varicocele (sudden onset)
  • paraneoplastic syndrome
    • neuromyopathy
    • protein-losing enteropathy

Laboratory

• Urinalysis for hematuria
• Complete blood count (CBC)
  • hypochromic anemia
  • erythrocytosis with paraneoplastic syndrome
• liver function tests
  • serum alkaline phosphatase (serum ALP)
  • serum gamma glutamyl transferase (serum GGT)
  • abnormal liver enzyme results may indicate metastatic disease
  • diminished serum albumin with protein-losing enteropathy
• serum Ca+2 may be increases with paraneoplastic syndrome

Radiology

• bone scan is indicated if serum alkaline phosphatase (ALP) is abnormal
• computed tomography (CT) scan
  • areas of fat identified in the tumor during abdominal CT, suggest angiomyolipoma
  • abdominal CT provides staging information including
    • extent of disease
    • liver metastasis
    • inferior vena cava (IVC) disease.
  • head or chest CT if metastases suspected
• chest x-ray (CXR) (rule out pulmonary metastases)
• abdominal ultrasound (US)
  • differentiating between cysts & masses
• abdominal magnetic resonance imaging (MRI)
  • if CT scan is indeterminate in ruling out inferior vena cava (IVC) disease.

Management

• see specific etiology
• angiomyolipoma (unequivocal diagnosis on CT scan)
  • if lesion <4 cm, observation is may be appropriate
  • if the lesion equals > 4 cm & patient is asymptomatic, resection is indicated
  • if the lesion > 4 cm & the patient is symptomatic
    • angiographic embolization or surgical removal
• solid renal mass, seen on radiographic studies without evidence of systemic spread of the neoplasm
  • partial (nephron-sparing) or radical nephrectomy*
  • alternately, percutaneous biopsy & pathology analysis
  • percutaneous cryoablation may be indicated for incidental renal neoplasm in poor surgical candidate

* MKSAP choice: 6.2 cm solid mass meets radiographic criteria for renal cell carcinoma

More general terms

• urologic neoplasm
• kidney disease; renal disease

More specific terms

• malignant kidney neoplasm (kidney cancer)
• renal oncocytoma; renal oxyphilic adenoma