Kidney Congenital Abnormalities, Cystic Lesions, Kidney Tumors

Question 1

List the 3 main stages of kidney development in utero

Answer 1

Pronephros
Mesonephros
Metanephros

Question 2

When does the pronephros appear? Where does it appear?

Answer 2

Pronephros forms around the 4th week

Moves from cervical region to caudal

Question 3

What structures join to form the ureteric bud?

Answer 3

Mesonephric duct and the cloaca

Question 4

What % of people are born with potentially significant malformations of the kidneys?

Answer 4

10%

Question 5

What is a horseshoe kidney?

Answer 5

Fused kidneys with a common pole under the inferior mesenteric artery

Pt has one fused kidney instead of two

Question 6

What is renal dysplasia?

Answer 6

Abnormal development of the kidney/nephrons

NOT related to neoplasia

Question 7

What is the primary pathological issue in Cystic Renal Dysplasia?

Answer 7

Abnormality in metanephric differentiation

Presence of immature elements like mesenchyme and cartilage

Question 8

What is the common gross appearance of Cystic Renal Dysplasia?

Answer 8

“Bunch of grapes”

See cysts and cartilage present outside of the kidney

Question 9

What is the inheritance of Childhood Autosomal Recessive Polycystic Kidney Disease (ARPKD)?

Answer 9

Autosomal recessive, so very rare

Question 10

What is the pathology associated with ARPKD?

Answer 10

Enlarged kidneys, but they retain a normal shape

Saccular dilations of the renal tubules

Question 11

What are the primary symptoms of Adult Polycystic Kidney Disease (APKD)?

Answer 11

May be asymptomatic
Pain
Colic
Mass
Hemorrhage

Question 12

What is the inheritance pattern of APKD?

Answer 12

Autosomal dominant

Question 13

Describe the pathology of APKD

Answer 13

Huge kidney size (normal shape)
Many cysts present in the kidney and liver
May also see intracranial berry aneurysms

Question 14

APKD

Treatment

Answer 14

Kidney transplant

Perhaps liver transplant too depending on function

Question 15

APKD

Prognosis

Answer 15

Renal failure in middle age/later life depending on the mutation present

Question 16

Acquired Cystic Disease

Where are the cysts seen?

Answer 16

Both the renal cortex and medulla

Question 17

Acquired Cystic Disease

What should you do follow-up tests for?

Answer 17

Detection of cancer

Question 18

Simple Cysts

Symptoms

Answer 18

Often asymptomatic

Question 19

Simple Cysts

Why would one need to be removed?

Answer 19

Removed for fear of renal cancer

Question 20

What is the general rule of thumb with all kidney tumors? (They are all presumed to be…)

Answer 20

All kidney tumors are presumed to be malignant until proven otherwise

Question 21

List the two benign kidney tumors

Answer 21

Oncocytoma

Angiomyolipoma

Question 22

Oncocytoma

What is it? What does it look like radiologically?

Answer 22

Benign tumor of the kidney, but looks like renal cell carcinoma by imaging

Question 23

Oncocytoma

How are they usually treated?

Answer 23

They are benign, but they are commonly removed for fear of malignancy

Question 24

Angiomyolipoma

What is this tumor made of? How can it be diagnosed?

Answer 24

Vessels, smooth muscle, and fat

May be diagnosed radiologically due to high fat density

Question 25

Angiomyolipoma

What complication are you worried about?

Answer 25

Worried about potential for rupture from large vessels present with abnormal walls

You would remove the angiomyolipoma to lower this risk

Question 26

Renal Cell Carcinoma

Triad of symptoms

Answer 26

Costovertebral pain
Mass
Hematuria

(Could also present with fever, malaise, weakness, weight loss, polycythemia, hypercalcemia, HTN)

Question 27

Where is Renal Cell Carcinoma most likely to metastasize?

Answer 27

Lungs and Bones

Question 28

Clear Cell RCC

Where is the mutation?

Answer 28

Mutation on chromosome 3 leading to inactivation of the VHL gene (a tumor suppressor)

Question 29

Clear Cell RCC

What does the mutation lead to an accumulation of?

Answer 29

Accumulation of transcription factor HIF-1a and an overexpression of its target genes

Facilitates cellular adaptation to tissue hypoxia

Question 30

Where does Clear Cell RCC commonly originate from?

Answer 30

Proximal tubular epithelium

Question 31

Describe the gross appearance of Clear Cell RCC

Answer 31

“Hypernephroma” due to similarity in appearance to adrenal gland

Question 32

Clear Cell RCC

Prognosis

Answer 32

Stage dependent

Question 33

Clear Cell RCC

Treatment

Answer 33

Surgical removal

RCC is very chemoresistant, so surgery is usually the best option

Question 34

VHL Syndrome

Pathogenesis

Answer 34

Multiple bilateral cysts and tumors with high vascularity and clear cells

Question 35

Papillary RCC

Describe the pathogenesis. How is it acquired?

Answer 35

Hereditary

See multiple bilateral tumors with papillary histology

Question 36

Papillary RCC

Prognosis

Answer 36

Better prognosis than Clear Cell RCC

Question 37

What is the most common pediatric renal cancer?

Answer 37

Wilm’s Tumor

Question 38

What is the mutation leading to Wilm’s tumor?

Answer 38

Loss of function mutations in WT1 and WT2

Question 39

Wilm’s tumor is a triphaic tumor. What are the three pathological characteristics?

Answer 39

Malignant blastema (small undifferentiated blue cells)
Tubules
Stroma

Question 40

What are treatment options for Wilm’s Tumor? How should you approach this treatment?

Answer 40

They are very soft tumors and it is crucial to correctly stage the tumor.

If there is extrarenal extension of the tumor, the child will need chemotherapy following removal of the tumor. If the tumor was limited to the kidneys, they will not need chemo.

Question 41

Wilm’s Tumor

Prognosis

Answer 41

Excellent - 90% survival at 5 years