Neoplasms of the Kidney and Urinary Tract

These flashcards review key facts on Wilms tumor, adult benign and malignant renal tumors, risk factors, molecular genetics, clinical presentations, and urinary bladder neoplasms.

What is the most common primary renal tumor in children?

Wilms tumor (nephroblastoma).

Between what ages does Wilms tumor most commonly present?

2–5 years of age.

What percentage of Wilms tumor cases are unilateral?

About 90% are unilateral (5–10% bilateral).

From what precursor lesion is Wilms tumor thought to arise?

Persistent metanephric tissue called nephrogenic rests.

Which tumor-suppressor gene on chromosome 11p13 is frequently mutated in Wilms tumor?

WT1 gene.

Name the syndrome characterized by Wilms tumor, aniridia, genital anomalies, and mental retardation.

WAGR syndrome.

What are the three histologic components of a Wilms tumor?

Blastemal, stromal (mesenchymal), and epithelial components (triphasic pattern).

Grossly, how does a Wilms tumor usually appear on cut section?

Soft, homogeneous, tan-gray with hemorrhage, cysts, and necrosis.

Which benign adult renal tumor is <0.5 cm and composed of cuboidal cells without atypia?

Papillary adenoma.

Which benign renal tumor contains blood vessels, smooth muscle, and fat and is associated with tuberous sclerosis?

Angiomyolipoma.

What is the main clinical risk posed by renal angiomyolipoma?

Spontaneous hemorrhage.

Which renal tumor is mahogany-colored, well-encapsulated, and often shows a central scar?

Oncocytoma.

From which part of the kidney do renal cell carcinomas arise?

Renal tubular epithelium (predominantly cortex).

List four major risk factors for renal cell carcinoma (RCC).

Cigarette smoking, hypertension, obesity, occupational cadmium exposure, and acquired polycystic disease on dialysis.

What is the male-to-female ratio for RCC incidence?

Approximately 2 : 1 (men twice as common).

Which type of RCC is the most common, accounting for 70–80% of cases?

Clear cell carcinoma.

Loss or mutation of which gene on chromosome 3p is central to clear cell RCC pathogenesis?

VHL (von Hippel–Lindau) gene.

Why does VHL loss promote tumor angiogenesis?

Stabilized HIF transcription factors up-regulate VEGF expression.

Clear cell carcinomas have a strong tendency to invade which large vessel?

The renal vein.

On gross inspection, what color is a clear cell RCC typically?

Yellow to white because of lipid-rich cytoplasm.

Which RCC subtype is associated with inherited or sporadic activating mutations of the MET proto-oncogene?

Papillary carcinoma.

Name two common microscopic features of papillary RCC.

Papillary architecture with foamy macrophages in cores and frequent psammoma bodies.

Which RCC subtype shows pale eosinophilic cells with perinuclear halos and generally has the best prognosis?

Chromophobe carcinoma.

What classic clinical triad is associated with RCC, though often incomplete?

Painless hematuria, palpable abdominal mass, and dull flank pain.

Production of which hormone-like factor by RCC can cause polycythemia?

Erythropoietin.

What is the most common site of distant metastasis from RCC?

Lungs.

What percentage of primary renal tumors are urothelial (transitional cell) carcinomas of the renal pelvis?

About 5–10%.

What is the dominant presenting symptom of urothelial tumors anywhere in the urinary tract?

Painless hematuria.

Name three malignant histologic types of urinary bladder cancer.

Urothelial (transitional cell) carcinoma, squamous cell carcinoma, and adenocarcinoma.

List two major carcinogenic exposures that increase bladder cancer risk.

Cigarette smoking and occupational exposure to arylamines or other industrial carcinogens (e.g., aniline dyes).

Which parasitic infection is strongly linked to squamous cell carcinoma of the bladder?

Urinary schistosomiasis (Bilharziasis).

How are urothelial tumors of the bladder morphologically classified (four categories)?

Benign papilloma, papillary urothelial neoplasm of low malignant potential, urothelial carcinoma (low/high grade), and carcinoma in situ (CIS).

What is the 5-year survival rate once bladder carcinoma invades deep muscle?

Less than 20%.

What is the principal treatment for localized renal cell carcinoma?

Radical nephrectomy (± adjuvant chemotherapy for advanced disease).