Practice question answers renal cysts
Practice question answers
Kidney mass I
© Jun Wang, MD, PhD
1. A. The history and pathological findings are most compatible with autosomal
dominant polycystic kidney disease.
Autosomal
recessive (childhood) polycystic kidney disease usually presents at
younger age with renal failure and pulmonary hypoplasia. Absence of cytological
atypia is not supportive of cystic renal
cell carcinoma. Medullary
sponge kidney is usually associated with stones, infections, and has
normal-sized kidney. Simple
cysts are usually incidental findings and not associated with
enlarged kidney and liver involvement.
2. B. Autosomal
dominant polycystic kidney disease is associated with mutation of
PKD1 or PKD2. NPHP mutation is seen in nephronophthisis.
PKHD mutation is seen in autosomal
recessive polycystic kidney disease. TFE3 abnormality is seen in Xp11
translocation type renal cell carcinoma. VHL mutation is seen in von
Hippel-Lindau syndrome and associated clear
cell type renal cell carcinoma, adrenal pheochromocytoma and
pancreatic neuroendocrine tumor.
3. A. Autosomal
dominant polycystic kidney disease is the third leading cause of
end-stage renal disease. Hepatocellular carcinoma may be associated with
various factors, including MET mutations seen in hereditary
papillary renal cell carcinoma. Liver fibrosis can be associated
with various conditions, including autosomal
recessive polycystic kidney disease. Patients with acquired
cystic renal disease has higher risk for renal
cell carcinoma. Respiratory failure is seen in autosomal
recessive polycystic kidney disease due to pulmonary hypoplasia.
4. B. The liver and
pancreatic cysts seen in autosomal
dominant polycystic kidney disease are lined by benign biliary epithelium. Congenital
portal fibrosis with increased bile ducts at periphery are seen in autosomal
recessive polycystic kidney disease. Hepatocytes with cytoplasmic clumps
of cytokeratin complexed with other proteins and neutrophilic portal
infiltrates are seen in alcoholic liver damage. Portal plasmacytic infiltrate
is seen in autoimmune hepatitis.
5. B. The clinical
setting of oligohydramnion, features of Potter syndrome, and microscopic
findings of dilated ducts perpendicular to cortical surface is consistent with autosomal
recessive polycystic kidney disease. Autosomal
dominant polycystic kidney disease is associated with progress renal
failure and commonly has adult onset. Renal
cell carcinoma is very rare in children. Medullary
sponge kidney is characterized by small cysts in medulla, normal cortex
and usually have normal renal functions. Simple
cysts are usually asymptomatic with normal renal function.
6. C. See discussion
to question 2.
7. D. Respiratory
insufficiency associated with pulmonary hypoplasia is the leading cause of
death in patients with autosomal
recessive polycystic kidney disease.
8. D. Congenital portal
fibrosis with increased bile ducts at periphery are seen in autosomal
recessive polycystic kidney disease. Benign hepatocytes with ground
glass appearing cytoplasm and lymphocytic infiltration at portal area are seen
in hepatitis. Fibrotic bands and nodular islands of hepatocytes are seen in
cirrhosis. Vacuolar changes of hepatocytes are seen in steatosis.
9. E. History of
polyuria, polydipsia, growth retardation and small kidney and cysts at
corticomedullary junction in a background of atropic tubules and interstitial
fibrosis are seen in nephronophthisis.
Autosomal
dominant polycystic kidney disease and autosomal
recessive polycystic kidney disease both have enlarged kidney with
cysts involving cortex and medulla. Absence of cytological atypia is not
supportive of cystic renal
cell carcinoma. Medullary
sponge kidney is characterized by small cysts in medulla, normal
cortex and usually have normal renal functions.
10. A. See discussion
to question 2.
11. A. End-stage
renal disease usually developed in a few years in patients with nephronophthisis.
There is no evidence showing these patients have increased risk for near future
liver failure, portal hypertension, or malignancies.
12. B. Impaired
renal tubular function is seen in development of nephronophthisis.
It is the pathological basis of polyuria, polydipsia and renal failure. Glomerular
inflammation and regeneration is seen in glomerular damage, such as glomerulonephritis.
Obstructions and recurrent bacterial infection is commonly associated with
congenital anomalies, such as ectopic
kidney and horseshoe
kidney, as well as multicystic
renal dysplasia or medullary
sponge kidney. It may be seen in patients with nephronophthisis,
but appears not to be the cause of renal failure.
13. D. Medullary
tubular dilation and normal cortex is most compatible with medullary
sponge kidney. Autosomal
dominant polycystic kidney disease and autosomal
recessive polycystic kidney disease have cortical involvement; cysts
of nephronophthisis
are located at the corticomedullary junction.
14. D. Defects of medullary
collecting duct development is associated with medullary
sponge kidney. Defects of both cortical and medullary collecting
ducts are seen in
autosomal
recessive polycystic kidney disease. Autosomal
dominant polycystic kidney disease is associated with developmental
defects in all parts of nephron.
15. B. The age,
history of recurrent urinary tract infection and hypertension, sonographic
findings of enlarged kidney, can be suggestive of multicystic
renal dysplasia in the absence of other symptoms, such as liver and pancreas
abnormalities. Although sonographic examination is used for initial screening, dimercaptosuccinic
acid renal scanning may show loss of renal function if sonographic exam is
inconclusive. Retrograde pyelography and ureteropyeloscopy are indicated for evaluation
of injury, hematuria, obstruction and possible urothelial epithelium, but have
limited use for renal function examinations. Urine cytology is usually not
useful for renal function or renal cyst/tumor evaluation unless it is high-grade
urothelial carcinoma.
16. D. The history and
pathological findings of no cortical medulla differentiation, as well as benign
cysts in a fibrotic background are most compatible with multicystic
renal dysplasia. Autosomal
recessive polycystic kidney disease usually have signs of Potter
syndrome. Hypoplasia
of kidney is characterized by a smaller kidney, although contralateral
kidney may have compensatory hypertrophy. Medullary
sponge kidney is characterized by small cysts in medulla, normal
cortex and usually have normal renal functions. Cysts of nephronophthisis
are located at the corticomedullary junction with clear cortical and medulla differentiation.
17. A. Kidney cysts containing
oxalate crystals in a patient with history of uremia is suggestive of acquired
kidney cysts associated with uremia, especially when there is no history of
hereditary cystic renal disease. Oxalate crystals are usually not seen in autosomal
dominant polycystic kidney disease, which usually has history of hypertension
prior to renal failure. Absence of cytological atypia is not supportive of
cystic renal
cell carcinoma. Multicystic
renal dysplasia usually has history of related presentations in early age. Cysts
of nephronophthisis
are located at the corticomedullary junction.
18. E. Cystic
changes of acquired
kidney cysts are associated with uremia, but not dialysis. Congenital cilia
malfunction is associated with autosomal
dominant polycystic kidney disease and nephronophthisis.
Defects of collecting duct differentiation is seen in autosomal
recessive polycystic kidney disease and medullary
sponge kidney. Renal parenchyma damage associated with recurrent
infections such as seen in chronic pyelonephritis usually presents with
interstitial scar, not cysts.
19. C. Patients with
acquired
kidney cysts have higher risk of developing renal
cell carcinoma, and the diagnosis is supported by radiologic findings of
kidney mass and confirmed by biopsy showing cytological atypia. Also see
discussion for question 17.
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