Genitourinary Radiology > Kidneys > Masses > Solid > RCC


Renal Cell Carcinoma

 

Renal cell carcinoma, also known as renal adenocarcinoma, hypernephroma, clear cell carcinoma, and malignant nephroma, accounts for 90-95% of primary renal cancers. The average age of diagnosis is 50-60 years, and patients present with hematuria (50%), flank pain (40%), palpable mass (35%), weight loss (25%), and paraneoplastic syndrome. The classic triad of hematuria, flank pain, and a palpable abdominal mass occurs in ~10% and indicates advanced disease. Thirty percent of patients present with metastatic disease with predilection for lung, soft tissue, bone, and liver. Risk factors include smoking, obesity, male (2:1), phenacetin and other analgesics, von Hippel-Lindau disease, chronic dialysis, family history.

CT: Enhancing mass (does not enhance as intensely as normal renal parenchyma) with distortion of parenchyma, collecting systemand contour abnormalities, calcifications in 10%, presence of filling defects in collecting system, renal veins and IVC. Look for adenopathy.

MRI: Signal characteristic variable depending on degree of hemorrhage and necrosis, calcifications not apparent with MRI, best for detecting venous invasion; good problem solving modality when CT is equivocal.

US: small tumors are generally hypoechoic, large tumors hyperechoic

Angiography: 95% are hypervascular with caliber irregularities of tumor vessels, prominent AV shunting, and venous lakes (tumor neovascularity). Pre-operative embolization is used to reduce the amount of blood loss during tumor resection.

Prognosis is based on staging. Robsons classification is still used but is being surplanted by TNM.

Robsons Classification:
Stage I—(50% 5-year survival) confined to renal parenchyma, < 7cm
Stage II—(50%) spread outside of renal capsule, but confined by Gerota’s fascia, or > 7cm
Stage III (35%)

  1. venous tumor extension to renal vein, infradiaphragmatic or supradiaphragmatic IVC
  2. regional lymph node metastases
  3. venous extension and regional lymph node metastases

Stage IV (15%)

  1. direct invasion beyond Gerota’s fascia
  2. distant metastases

TNM classification bases staging of RCC on size with a cutoff of 7cm for stage I and II, invasion of Gerota’s fascia (stage III), renal vein, and IVC, lymph node and metastatic disease (stage IV). 5-year survival based on this classification system is: stage I/II = 50%, stage III = 35%, stage IV = 15%. Late post nephrectomy metastatases occur in 10%. Long term survival is possible with untreated tumor

 

 

 

Gray scale ultrasound (1) and enhanced CT scan (2) show a large right renal mass. The mass (M) is distorting the renal contour and is hyperechoic. On CT, the mass has varying attenuation: low areas consistent with necrosis (n) and enhancing areas consistent with viable tumor (t). Note that the enhancing tumor is less enhancing than normal functional renal parenchyma (p).

 

 

 

 

MRI of the kidneys employing T1 wegithed axial images (1) and coronal MR venogram (2). The axial image shows a large mass in the right kidney (M) and the arrow points to right renal vein invasion by the tumor. Coronal MR venogram confirms tumor thrombus in the IVC (arrow) in an advanced stage renal cell carcinoma.

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