Click here to return to our home page  

Multicystic dysplastic kidney

NHS Logo

CAR home
    Renal tract     dilation and     hyronephephrosis
      Upper renal       tract       obstruction
      Lower renal       tract       obstruction
    Multicystic     dysplastic     kidney
    Polycystic kidney
    Renal agenesis


Introduction Antenatal Postnatal West Midlands Data



Multicystic dysplastic kidney (type II Potter) along with hydronephrosis in one of the most commons causes of abdominal mass in the neonate. It arises from a failure in the branching of ureteric buds that induce nephron formation during early renal development. Multicystic dysplastic renal disease is the most common renal cystic disease has no association with polycystic kidney disease (PCKD). Unlike PCKD, multicystic dysplastic renal disease can be unilateral or bilateral, and occurs sporadically.
A multicystic dysplastic kidney contains non-communicating multiple cystic spaces varying in size and has no functioning renal tissue. It is always associated with a blocked ureter (ureteric atresia). The blockage of the ureter leads to a damming back of any urine produced within the kidney and rapidly causes cysts to form in the renal parenchyma. If the disease is bilateral then there will be no liquor (anhydramnios) and pulmonary hypoplasia leading to death in early neonatal life will result. A unilateral multicystic dysplastic kidney with good liquor volume has a good prognosis.

Top of the page


Ultrasound scanning is especially well suited to differentiating between fluid and solid tissues, and therefore the multicystic kidney has a high pick-up rate antenatally. The differential diagnosis includes a hydronephrosis kidney in which the calyces are dilated, but is distinguished by the calyces communicating with each other via the renal pelvis. Polycystic renal disease normally presents as bright large kidneys and therefore is seldom confused. Complex cystic masses in both renal fossae will point towards multicystic renal disease as the cause, but if the bladder is present and either dilated, or thick walled, this would tend to suggest some form of bladder outflow obstruction.

Multicystic dysplastic renal disease can be bilateral, unilateral, or segmental. The size of the cysts determines the size of the kidneys, which can be multicystic and enlarged or shrunken, irregular, and hyper-echogenic. Bilateral multicystic kidneys are associated with severe oligohydramnios and the fetal bladder will be absent on ultrasound.

If the lesion is unilateral other anomalies should be sought, but in isolation this anomaly, although easily seen on ultrasound scanning is most likely to cause no major health problems for the individual concerned. It is customary to repeat the ultrasound examination later in pregnancy, to look for possible pressure effects of the abdominal mass. If one kidney is massively dilated causing circulatory failure in the fetus, consideration may be given to decompression or delivery. These cases are very rare, and the most common outcome is for the multicystic kidney to remain the same size with the fetus and baby growing normally around it.

There is little data to suggest that multicystic renal disease is linked to other anomalies. The question is sometimes asked whether this finding increases the risk of other anomalies, and a careful search of the rest of the fetus should be part of the assessment of the case. Most fetal medicine experts would say that the chances of trisomy are increased, but by how much would be debated. In a woman who has no other risk factors and has a low risk prediction following nuchal translucency or serum screening the risk of invasive testing almost certainly outweighs the risks of trisomy, but these issues may need to be explored with the parents during the discussions of the implications of the diagnosis.

Top of the page


Severe bilateral multicystic renal disease is incompatible with life due to the associated oligohydramnios and pulmonary hypoplasia; these cases should be managed conservatively. In cases where one kidney is affected postnatal assessment can be undertaken at any time, as the appearances are not affected by urine output in the fetus. The affected kidneys may be left to atrophy, however prophylactic nephrectomy can be carried out to reduce hypertension and the possibility of malignant change within the remaining cystic mass. In general terms a unilateral multicystic dysplastic kidney will be managed conservatively whilst asymptomatic, or an increase in size.

Top of the page


Information to follow

Top of the page

© Perinatal Institute 2011