Neoplasms of the Kidney

Question 1

Kidney neoplasms

Answer 1

1. Renal cell carcinoma - m
2. Urothelial carcinoma - m
3. Nephroblastoma (Wilms) - m
4. Angiomyolipoma - b

Question 2

Features of renal cell carcinoma

Answer 2

• 85% of malignant renal tumours in adults
• arises from renal tubular epithelium
• 6th-7th decades of life, M:F 2:1

Question 3

Types of renal cell carcinomas

Answer 3

1. Clear Cell RCC (70-80%) - proximal tubules
2. Papillary RCC (10-15%) - distal tubules
3. Chromophobe RCC (5%) - intercalated cells of CT

Question 4

Features of clear cell RCC

Answer 4

• sporadic, most common
• familial, associated with von Hippel Lindau (VHL) syndrome - chromosome 3p deletions & mutations of VHL tumour suppressor gene

Question 5

Clinical features of renal cell carcinoma (5)

Answer 5

1. Painless hematuria
2. Mass in flank
3. Fever - due to necrosis
4. Costovertebral pain
5. Paraneoplastic syndromes

Question 6

Gross morphology of renal cell carcinoma

Answer 6

• solitary, unilateral mass with a circumscribed appearance
• yellowish cut surfaces with foci of necrosis & hemorrhage
• invasion of renal vein
• tendency to metastasise widely

Question 7

Microscopy of renal cell carcinoma

Answer 7

• polygonal cells w clear cytoplasm arranged in tubular/trabecular architecture
• delicate branching vasculature
• invasion of renal vein/its branches

Question 8

Features of urothelial carcinoma

Answer 8

• involves areas of kidney lined by urothelium
• may be multifocal, assoc w urothelial carcinoma of the ureter & bladder
• types: papillary urothelial carcinoma, invasive urothelial carcinoma

Question 9

Features of nephroblastoma

Answer 9

• paediatric tumour usually diagnosed between ages 2-5

- associated w congenital malformations

Question 10

Clinical features of nephroblastomas

Answer 10

• large abdominal mass - usually unilateral, may cause intestinal obstruction
• fever due to necrosis & hemorrhage
• hematuria
• metastases - hematogenous & lymphatic spread to lungs, liver, brain, lymph nodes
• treat: nephrectomy & chemo - good prognosis

Question 11

Gross morphology of nephroblastomas

Answer 11

• well circumscribed greyish white, soft mass
• foci of hemorrhage, cysts, necrosis
• begins in renal cortex, replaces entire kidney

Question 12

Microscopy of nephroblastomas

Answer 12

• sheets of small blue cells (blasternal component)
• abortive tubular & glomeruloid structures (epithelial component)
• spindle-shaped cells (stromal component)
• triphasic nephroblastoma contains all 3 components
• heterologous elements eg striated/smooth muscle & cartilage may be found

Question 13

Features of angiomyolipomas

Answer 13

• most common mesenchymal tumour of the kidney
• adpose cells, hyoid spindle cells, blood vessels
• most commonly in kidneys, but can also occur in the liver, retroperitoneum, lungs
• occurs at all ages but usually resected in pt ~40y or older

Question 14

Pathogenesis of angiomyolipomas

Answer 14

• sporadic

- associated with tuberous sclerosis

Question 15

Clinical features of angiomyolipomas

Answer 15

• usually accurately diagnosed on CT imaging due to large fat content
• benign but may rupture & bleed w serious/fatal clinical outcomes

Question 16

Morphology of angiomyolipomas

Answer 16

G:

• unencapsulated
• variegated cut surface with yellow (fatty) areas

M:

• mixture of myoid spindle & epithelioid cells, adipocytes & blood vessels, often thick-walled
• myoid cells show immunostaining for HMB-45