A 56-year-old man with hypertension presents with a 2-week history of left-sided flank pain. Urinalysis shows microscopic hematuria and a CT scan (Figures 73-1 and 73-2) demonstrates a solid left renal mass. Work-up for metastatic disease was negative. A biopsy confirmed renal cell carcinoma, and a radical nephrectomy was performed.
Renal cell carcinoma. CT shows solid mass in the left kidney (arrow). (Reproduced with permission from Michael Freckleton, MD.)
CT with contrast in the same patient shows the solid hypodense renal cell carcinoma mass (arrow) in the left kidney and contrasting normal parenchyma. The contrast is taken up better by the remaining normal kidney tissue and the tumor becomes more visible. (Reproduced with permission from Michael Freckleton, MD.)
Renal tumors are a heterogeneous group of kidney neoplasms derived from the various parts of the nephron. Each type of tumor possesses distinct genetic characteristics, histologic features, and, to some extent, clinical phenotypes that range from benign (approximately 20% of small masses) to high-grade malignancy. Ninety percent to 95% of kidney neoplasms are renal cell carcinomas (RCCs).1
RCC comprises 2% to 3% of all visceral malignant diseases in adults and is the ninth most common cancer.1 These cancers are more common in men than women (approximately 1.6:1).2 The incidence in the United States is increasing.
A similar percentage was reported for children in the Children's Oncology Group study in which 3.7% of 3250 patients enrolled were found to have unilateral RCC (median age, 12.9 years [range, 1.9–22.1 years].3 The male-to-female ratio was approximately 1:1.
An estimated 62,700 cases in the United States were diagnosed and approximately 14,240 deaths occurred in 2016 from kidney and renal pelvis cancer (2.4% of all cancer deaths).4 The age-adjusted incidence rate was 15.6 per 100,000 persons with a median age at diagnosis of 64 years.4
Lifetime risk of kidney and renal pelvis cancer is 1.6% (approximately 1 in 63 people will be diagnosed during their lifetime).4
Approximately 2% to 3% of cases are familial (e.g., von Hippel-Lindau syndrome).1
Metastatic disease at presentation occurs in 10% to 33%; the most common sites of distant metastases (in descending order) are lung (with or without mediastinal or hilar nodes), bone, upper abdomen (including the tumor bed, adrenal gland, contralateral kidney, and liver), brain, and other sites (e.g., skin, spleen, heart, diaphragm, gut, connective tissue, and pancreas).2,5 In the report of children with RCC, distant metastases were present in 23 cases (19.2%).3
ETIOLOGY AND PATHOPHYSIOLOGY
The majority of renal tumors fall into the ...