Kidney nontumor / medical renal

Developmental & cystic diseases

Dysplasia / hypoplasia / agenesis

Last author update: 1 December 2011
Last staff update: 21 July 2023 (update in progress)

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PubMed Search: Cystic renal dysplasia

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Dysplasia / hypoplasia / agenesis. website. Accessed September 22nd, 2023.
Definition / general
  • Congenital cystic anomaly of the kidney caused by abnormal metanephric differentiation, occurring by week 20 in utero
  • Enlarged, cystic kidneys with disorganized parenchyma and numerous cysts
  • Immature tubules surrounded by mesenchymal collars and islands of immature mesenchyme are present between the cysts
  • Also known as multicystic renal dysplasia
  • Most common pediatric cystic renal disease
  • Most often a sporadic event but familial cases have been reported
  • 90% are associated with ureteropelvic obstruction, ureteral agenesis, atresia or reflux; 10% have unknown cause
  • Bilateral disease should raise the suspicion of occult disease in parents
  • Also associated with cardiac malformations, Meckel-Gruber syndrome (eMedicine), inherited metabolic abnormalities (Pediatr Nephrol 2007;22:2119), thanatophoric dysplasia type 1 (Genet Couns 2006;17:407) and other familial syndromes (Am J Med Genet 1996;63:332)
Clinical features
  • Most common cause of neonatal abdominal masses; presents as flank mass or pyelonephritis
  • In bilateral disease, neonates may also display oligohydramnios and pulmonary hypoplasia
  • If blastema present, patient is at a slightly higher risk for Wilms tumor
  • Segmental dysplasia is seen in children with duplex (duplicated) kidney (incomplete fusion of upper and lower poles)
Case reports
  • Newborn with bilateral renal dysplasia, severe pancreatic fibrosis, intrahepatic biliary dysgenesis and total situs inversus with normal cytogenetics (Hum Pathol 1988;19:871)
Gross description
  • Enlarged kidney distorted by variably sized cysts that may involve one or both (20%) kidneys
  • Indistinct corticomedullary junction
  • Usually associated with ureteropelvic obstruction or ureteral atrophy / atresia
Gross images
Images hosted on other servers:

Multiple cysts of various sizes

With small bladder

Cysts are smooth
lined, no normal
kidney tissue
is apparent

With ipsilateral hypoplasia of ureter

Due to congenital
urethral stenosis with
hypertrophic bladder wall
and bladder diverticulum

Microscopic (histologic) description
  • Disorganized parenchyma that is distorted by cysts of various sizes, lined by flattened to cuboidal epithelium
  • May contain nodular blastema (undifferentiated cells), islands of undifferentiated mesenchyme, cartilage (10% - 20%), immature collecting ducts with fibromuscular collars and primitive glomerular structures
Microscopic (histologic) images

Images hosted on other servers:

Large cysts lined by
flattened epithelium
with fibrotic and
cartilaginous stroma

Islands of cartilage in stroma

Multiple small cysts and
immature tubules, surrounded
by immature connective tissue with
abortive glomerular structures

Immature mesenchyme and cysts

Differential diagnosis
Additional references
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