Multicystic Dysplastic Kidney



  • Multicystic dysplastic kidney (MCDK) disease is the most severe type of cystic renal dysplasia and is characterized by multiple, noncommunicating cysts which are divided by dysplastic tissue.
  • In general, there is no functioning renal tissue in a MCDK.
  • Involutes over time (usually within the first 5 years)


  • Incidence is 0.3 to 1 in 1,000 live births
    • Most cases are detected antenatally.
  • Affects boys > girls
  • Left kidney > right kidney
    • Usually unilateral but can be bilateral


  • Initial growth of the ureteric bud is normal; then renal development halts at a later stage.
  • Histology shows disordered renal tissue with areas of undifferentiated mesenchymal cells, abnormal differentiation (i.e., cartilage), rare nephrons.
  • Etiology unknown; recent studies suggest genetic cause.

Commonly Associated Conditions

Associated anomalies of contralateral GU tract include the following:

  • Vesicoureteral reflux (VUR), most common, occurs in ~25%.
  • Renal hypoplasia
  • Ureterocele
  • Ureteropelvic junction (UPJ) obstruction
  • Genital anomalies

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