Autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease
Diagnosis in short
Micrograph showing polycystic kidney disease in the context of autosomal dominant polycystic kidney disease. H&E stain.
LM	cortical cysts lined by simple flattened epithelium, normal renal tubules interspersed between cysts or tubules as seen in end-stage kidney (thyroidization), +/-fibrosis (late-stage), +/-calcifications
Subtypes	PKD1 gene associated, PKD2 gene associated
LM DDx	acquired cystic renal disease
Molecular	mutation in PKD1 gene or PKD2 gene
Gross	enlarged kidney composed to many cysts
Site	kidney - see cystic kidney diseases
Associated Dx	end-stage kidney, liver cysts; PKD1 associated: cerebral aneurysms; PKD2 associated: colonic diverticula, aortic aneurysm, mitral valve prolapse
Clinical history	family member with polycystic kidney disease
Prevalence	uncommon
Radiology	polycystic kidneys
Prognosis	progressive renal failure
Treatment	+/-nephrectomy, dialysis, renal transplant

Autosomal dominant polycystic kidney disease, abbreviated ADPKD, is a common genetic cause of chronic renal failure.

Surgically removed to due to symptoms (mass effect); native nephrectomy often done concurrently with renal transplant.

General

Etiology

• Mutation in PKD1 gene or PKD2 gene.
• Is classified in a large group of diseases - ciliopathies.

PKD1 related disease:

• Encodes polycystin.
• Death at ~53 years.
• Associated with cerebral aneurysms.

PKD2 related disease:

• Death at ~69 years.
• Associated with colonic diverticula, aortic aneurysm, mitral valve prolapse.

Liver cysts and PKD

General

Features:

• Most common extra-renal manifestation of PKD; dependent on age, sex and renal function:
  • Age dependence:
    • 10-17% <40 years old have liver cysts.
    • 70-75% >60 years old have liver cysts.
  • Renal function:
    • 60-70% of patients with end-stage renal disease (ESRD) and near-ESRD.
  • Females more often affected.
• Hepatic function usu. preserved.

Complications:

1. Infected cyst.
2. Cholangiocarcinoma.

Microscopic

Features:

• Von Meyenburg complexes:
  • Cluster of dilated ducts with "altered" bile.
  • Surrounded by collagenous stroma.

See: Medical liver disease.

Gross

Features:

• Thin walled cysts.
  • Number of cysts:
    • If you can count 'em it favours acquired renal cystic disease... if you can't it favours the genetic condition.

Microscopic

Features:

• Cortical cysts lined by simple flattened epithelium.
• Normal renal tubules interspersed between cysts or tubules as seen in end-stage kidney (thyroidization).
• +/-Fibrosis (late-stage).
• +/-Calcifications.^{[citation needed]}

DDx:

• Acquired renal cystic disease - rarely.
  • Morphologically similar to acquired renal cystic disease.
  • It is said that "... if you can count 'em it's simple cysts; if you can't it's polycystic (renal disease)."

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Left Kidney, Nephrectomy: 
- Polycystic kidney with changes of chronic renal failure (thyroidization), 
  consistent with polycystic kidney disease. 
- NEGATIVE for malignancy. 

See also

• Cystic kidney diseases.
• Benign cortical cyst of kidney.