Atlas of pathophysiology, 2 Edition

Part II - Disorders

Renal Cancer

Renal cancer (nephrocarcinoma, renal cell carcinoma, hypernephroma, or Grawitz's tumor) usually occurs in older adults. Although the incidence of this malignancy is rising, it accounts for only about 2% of all adult cancers. Most renal tumors are metastases from primary cancer sites. Renal pelvic tumors and Wilms' tumor occur primarily in children. Kidney tumors are large, firm, nodular, encapsulated, unilateral, and solitary; they're classified histologically as clear-cell, granular, or spindle-cell tumors.

Causes

Primary cause unknown

Predisposing factors

·   Tobacco use

·   Environmental toxins

·   Analgesic abuse

·   Advancing age

Age Alert

Renal cancer is more common in men than in women and peaks in incidence between ages 50 and 70.

Pathophysiology

Renal cancers arise from tubular epithelium and can occur anywhere in the kidney. The tumor margins are usually clearly defined, and the tumors can include areas of ischemia, necrosis, and focal hemorrhage. Tumor cells vary from well differentiated to very anaplastic.

Signs and symptoms

Classic clinical triad

·   Hematuria—microscopic or gross; may be intermittent; suggests spread to renal pelvis

·   Pain—constant abdominal or flank pain (may be dull); if cancer causes bleeding or blood clots, acute and colicky

·   Palpable mass—generally smooth, firm, and nontender

·   All three present in only about 10% of patients

Other signs

·   Fever

·   Hypertension

·   Rapidly progressing hypercalcemia

·   Urine retention, edema in the legs

·   Nausea, vomiting, weight loss

Diagnostic test results

·   Computed tomography scan, I.V. and retrograde pyelography, ultrasound, cystoscopy (to rule out associated bladder cancer) and nephrotomography, and renal angiography identify the presence of the tumor and help differentiate it from a cyst.

·   Liver function tests show increased levels of alkaline phosphatase, bilirubin, alanine aminotransferase, and aspartate aminotransferase.

·   Prothrombin time is prolonged.

·   Urinalysis reveals gross or microscopic hematuria.

·   Complete blood count shows anemia, polycythemia, and increased erythrocyte sedimentation rate.

·   Serum calcium levels are elevated.

Treatment

·   Radical nephrectomy, with or without regional lymph node dissection—the only chance of cure

·   High-dose radiation—used only if the cancer spreads to the perinephric region or the lymph nodes or if the primary tumor or metastatic sites can't be fully excised

·   Chemotherapy—results usually poor against kidney cancer

·   Biotherapy (interferon and interleukins)—commonly used in advanced disease; has produced few durable remissions

·   Hormone therapy

·   Pain control (analgesics)

P.369

TWO FORMS OF RENAL CANCER

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