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.



Back to practice questions renal cysts
Back to kidney masses
Back to contents

Comments

Popular posts from this blog

Contents

Anemia

Lymphoid neoplasms