Renal Neoplasms

Question 1

Renal tumors: benign vs malignant

Answer 1

Benign
Renal Papillary Adenoma
Angiomyolipoma
Oncocytoma

Malignant
Renal cell carcinoma and variants
Urothelial cell carcinoma of the renal pelvis
Wilms Tumor (Nephroblastoma)

Question 2

Renal Papillary Adenoma(Renal Cortical Adenoma)

Answer 2

Currently papillary adenoma is defined as being less than 5 mm in size (benign)

Arise from tubular epithelium

Cytogenetics: Contains chr +7 and +17 and -Y similar to papillary renal cell carcinoma.

Cannot have any clear cell features

Question 3

Angiomyolipoma of Kidney

Answer 3

Benign neoplasm containing vessels, muscle and fat

Present often with tuberous sclerosis

** Susceptible to spontaneous retroperitoneal hemorrhage

Question 4

Oncocytoma

Answer 4

Epithelial cell neoplasm
Abundant cytoplasmic mitochondria
Mahogany brown well encapsulated mass with central scar (stellate, often)
Can achieve large size
May closely simulate renal cell carcinoma

acidophilic, granular cytoplasm **

Question 5

Other Benign Renal Tumors

Answer 5

Juxtaglomerular Cell Tumor is a rare renal tumor presenting in young adulthood with severe hypertension due to excessive renin secretion.

Question 6

Renal Cell Carcinoma

Answer 6

Arises from renal tubular epithelium
Risk Factors: Cigarette smoking , hypertension, obesity, estrogens, asbestos, chronic renal disease, tuberous sclerosis*, acquired cystic disease
Most are sporadic; but ~4% are hereditary- autosomal dominant, younger patients
- Von Hippel-Lindau (most patients will develop renal clear cell carcinoma)
- Hereditary papillary carcinoma (Trisomy 7, MET proto-oncogene 7q31)
- Hereditary leiomyomatosis and renal cell carcinoma (fumarate hydratase gene)

Question 7

Types of renal cell carcinoma

Answer 7

Renal cell carcinomas have a common origin from renal tubular epithelium but have distinct morphologic and genetic features
Clear cell carcinoma (70-80%)
Papillary carcinoma (10-15%)
Chromophobe carcinoma (5%)
Xp11 translocation carcinoma (occurs in young patients)**
Collecting duct carcinoma (~1%)

Question 8

clear cell vs papillary carcinoma

Answer 8

Clear cell carcinoma (Non-papillary)
95% are sporadic
98% have short arm of chromosome 3 deletion
Inactivation/loss of VHL gene (Hereditary clear cell)

Papillary carcinoma
Trisomy 7, 17 and loss of Y chromosome (Sporadic)
Trisomy 7 (Hereditary papillary)

Question 9

Important Characteristics

of renal cell carcinoma

Answer 9

Tendency to large size & widespread early metastases before local signs/symptoms

Tendency to invade renal vein

GREAT MIMIC: paraneoplastic syndromes & unusual presentations of metastases (10-20% patients)

Question 10

Renal Cell Carcinoma Classic Triad of symptoms

Answer 10

Hematuria (50%) (often only microscopic)
Costovertebral pain (20%)
Palpable flank mass (10%)

All 3 present in

Question 11

what targeted drug therapy has helped against renal cell carcinoma?

Answer 11

therapies against the vascular endothelial growth factor (VEGF) pathway have extended the lives of patients with advanced disease significantly

Question 12

TNM staging for kidney cancer– what happens at T4?

Answer 12

extension through Gerota’s fascia

Question 13

Urothelial Carcinoma

Answer 13

(Transitional cell carcinoma)

Urothelial tumors of the upper urinary tract progress through histologic changes from hyperplasia to dysplasia to frank CIS * in a significant proportion of patients
Urothelial carcinomas (* renal pelvis, ureter, bladder) tend to be multifocal
Urothelial tumors of the upper urinary tract are more often invasive compared to bladder urothelial carcinomas *
Ureteral tumors occur more commonly in the lower than in the upper ureter. Overall, about 70% ** of ureteral tumors occur in the distal ureter, 25% in the mid-ureter, and 5% in the proximal ureter

Question 14

urothelial carcinoma presenting signs

Answer 14

Most common presenting sign is hematuria
Can be associated with obstruction and hydronephrosis
Computed tomographic (CT) Urography preferred diagnostic test

frequent mitotic figures

Question 15

Wilms Tumor(Nephroblastoma)

Answer 15

Most common primary malignant renal tumor of childhood
Peak incidence between 2 and 5 years

10% occur as part of multiple different malformation syndromes
The most common presentation is detection of an abdominal mass or swelling without other signs or symptoms.

Associated with loss of function mutations of tumor suppressor and transcription genes including: WT1, p53, FWT1 and FWT2
95% solitary and 5% bilateral renal involvement
Tumor histology is linked to patient outcome

Question 16

Wilms tumor histology

Answer 16

Nephrogenic rests frequently seemed associated with tumor and can indicate bilateral disease

• Typical triphasic histology (favorable) mimics development of normal kidney: blastema, tubular epithelial cells and stroma
• Anaplastic histology ** (poor prognosis) has extreme cellular pleomorphism (resistant to chemotherapy)

Question 17

Fetal Kidney Histology

Answer 17

normally:

fetal kidney at low power. Beneath thecapsuleis a nephrogenic zoneof primitive blue cells from which the new cortex, including glomeruli will arise.

Question 18

Wilms Tumor Gross Pathology

Answer 18

Well-circumscribed margins
Tan-to-gray color
Tumor in lower pole
of kidney

Question 19

“Small Round Blue Cell Tumors”

of Childhood

Answer 19

Acute Leukemia
Neuroblastoma
Retinoblastoma
Wilms Tumor
Ewing’s Sarcoma
Medulloblastoma
Hepatoblastoma
Rhabdomyosarcoma
Primitive Neuroectodermal Tumor
Mesothelioma, Small Cell-type

Question 20

Most critical factors in wilms tumor prognosis

Answer 20

Most Critical Factor:
Favorable vs Unfavorable Histology

absence or presence of diffuse anaplasia