Tumors of the Kidney & Urinary Tract

Question 1

Common benign tumors of the kidney

Answer 1

• renal papillary adenoma
• renal fibroma or hamartoma
• angiomyolipoma
• oncocytoma
• metanephric adenoma

Question 2

Characteristics of renal paillary adenoma

Answer 2

1. Well circumscribed nodules within the cortex, small
2. 7 – 22 % at autopsy
3. Surgically removed since they are considered “early cancers.”

Question 3

Characteristics of renal fibroma or hamartoma

Answer 3

• Renomedullary Interstitial Cell Tumor
• Fibrous, less than 1 cm, within pyramids
• no malignant tendency

Question 4

Characteristics of angiomyolipoma

Answer 4

• Vessels, smooth muscle and fat
• 25 -50% in patients with tuberous sclerosis.

Question 5

Characteristics of oncocytoma

Answer 5

• Eosinophilic epithelial cells, numerous mitochondria
• 5 – 15% of all renal neoplasms.
• Some cases are most common within family groups.

Question 6

Clear cell carcinoma: incidence, clinical, imaging

Answer 6

• Incidence: most common; male > female
• Clinical:
  
  • Hematuria
  • Arises @ renal cortex ==> invade the renal vein + can extend into the inferior vena cava
  • metastases: Regional lymph nodes + often as multiple nodules in the lungs.
• Imaging:
  
  • Ball-like mass of renal cortex;
  • Engorged, tumor-filled renal vein with extension to inferior vena cava.
  • Look for metastatic disease.

Question 7

Clear cell carcinoma: pathology

Answer 7

• Gross: single tumor (multifocal and bilateral in Von Hippel-Lindau disease),
  
  • spherical, yellowish gray mass, patchy
• Histology:
  
  • cell types: clear, granular, and spindle.
  • most = clear + granula
  • Spindle cell types or sarcomas tend to grow and spread more quickly than the other kinds of RCCs.

Question 8

Clear cell carcinoma: genetics

Answer 8

• VHL gene: both familial and sporadic tumors
  
  • lost or mutated
• loss of sequences @ short arm chromosome 3

Question 9

clear cell carcinoma: staging/grade & prognosis

Answer 9

• Grading = Fuhrman’s criteria (1-4)
  
  • 1-2 = better survival vs. 3-4
• 45% 5-yr survival
  
  • higher w/out metastasis and lower w/renal vein invations

Question 10

Papillary carcinoma (Chromophillic): incidence, pathology, genetics, prognosis

Answer 10

• Incidence: Represent 10% to 15% of renal cancers.
• Pathology:
  
  • Gross: Unlike clear cell RCCs, papillary carcinomas are frequently multifocal.
  • Histology: Papillary growth pattern.
• Genetics: Occurs in both familial and sporadic forms. Not associated with 3p deletions.
  
  • sporadic: trisomies 7, 16, and 17 and loss of Y
  • familial: trisomy 7 (MET locus = protooncogene)
• Prognosis: Better than clear cell RCC

Question 11

Chromophobe renal carcinoma: incidence, pathology, genetics, prognosis

Answer 11

• Incidence: Represents 5% of renal cell cancers
• Pathology: prominent cell membranes and pale eosinophilic cytoplasm + halo around the nucleus
• Genetics: multiple chromosome losses and extreme hypodiploidy.
• Prognosis: Excellent compared with that of the clear cell and papillary cancers; similar to oncocytomas.

Question 12

Collecting duct carcinoma: incidence, pathology, genetics, prognosis

Answer 12

• Incidence: Represents approximately 1% or less
• Pathology: Nests of malignant cells enmeshed within a prominent fibrotic stroma, typically in a medullary location.
• Genetics: chromosomal losses/deletions; no distinct pattern
• Prognosis: Associated with aggressive behavior and poor prognosis.

Question 13

Types of familial RCC

Answer 13

• Von Hippel-Lindau (VHL) syndrome
  
  • gene implicated in both familial and sporadic
• Hereditary papillary carcinoma
  
  • autosomal-dominant form
  • bilateral tumors w/papillary historlogy
  • MET protooncogene

Question 14

TNM staging system

Answer 14

• T=tumor size, N=lymph nodes, M=metastasis
• Stage 1: small (<7cm), limited to kidney
• Stage 2: >7cm, limited to kidney
• Stage 3:
  
  • any size + spread to lymph node + no metastasis
  • spread into fatty/tissue or large veins + no lymph node spread + no metastasis
• Stage 4: distant metastasis