**5. Multicystic dysplastic kidney disease (Potter type II)**

Definition: Multicystic dysplastic kidney (MCDK) presents with unilateral/bilateral enlarged kidneys with parenchyma replaced by multiple, noncommunicating cysts [3].

Incidence: 1:1000–1:5000; more common in males (2:1), but females have a worse prognosis (twice more likely to have bilateral forms and four times more likely to have aneuploidy).

Pathology: in normal kidney embryology, the ureteric bud signals the metanephros to form nephrons. Early ureter obstruction or atresia prevents the signaling so the metanephric tissue does not form nephrons, resulting in dysplastic cystic tissue. Segmental/partial MCDK may result from a duplex ureter [2].

Ultrasound findings:

Unilateral (75–80%): the diagnostic is made in the presence of multiple cyst structure in the renal fossa, significantly larger than normal kidneys. The bladder is normal. Amniotic fluid is within the normal range [3].

Bilateral (20%): both kidneys are multicystic; the bladder cannot be visualized, and severe oligoamnios is associated.

Partial (rare): in rare cases of duplex kidney, only part of the kidney may be involved, more frequently the superior pole.

Differential diagnosis:


Clinical facts:

Clinical facts:

normal until 20 weeks.

• Recurrence risk is 25%.

result from a duplex ureter [2].

• Not associated with chromosomal anomalies.

**Figure 5.** Autosomal recessive polycystic kidney disease.

278 Congenital Anomalies - From the Embryo to the Neonate

• Thirty to fifty percent die in the neonatal period.

Bardet-Biedl, Beckwith-Wiedmann, Perlman, Elejade).

• ARPKD is classified in perinatal, neonatal, infantile, and juvenile form.

• Juvenile form has less renal involvement but marked hepatic fibrosis.

• When diagnosed prenatally, termination should be offered (**Figure 5**).

**5. Multicystic dysplastic kidney disease (Potter type II)**

kidneys with parenchyma replaced by multiple, noncommunicating cysts [3].

• Survivors develop systemic hypertension (75%) and portal hypertension (44%).

• Cases diagnosed in utero end with stillbirth or neonatal death.

• Enlarged, hyperechogenic kidneys may be present in many syndromes (Meckel-Gruber,

• Most cases are diagnosed by 24 weeks, but you must keep in mind that kidneys may look

Definition: Multicystic dysplastic kidney (MCDK) presents with unilateral/bilateral enlarged

Incidence: 1:1000–1:5000; more common in males (2:1), but females have a worse prognosis (twice more likely to have bilateral forms and four times more likely to have aneuploidy).

Pathology: in normal kidney embryology, the ureteric bud signals the metanephros to form nephrons. Early ureter obstruction or atresia prevents the signaling so the metanephric tissue does not form nephrons, resulting in dysplastic cystic tissue. Segmental/partial MCDK may


**Figure 6.** Multicystic kidney (unilateral).
