ABSTRACT
Before the introduction of routine antenatal ultrasound scan, multicystic dysplastic kidney (MDK) was regarded as an uncommon anomaly which generally presented as an abdominal mass in the newborn period. Nephrectomy was the standard form of management. However, it is now clear that the prevalence of asymptomatic unilateral multicystic kidneys in the general population is far higher than was previously suspected, with one recent study indicating a figure of 1:2500-3000 live births. The majority of MDKs are small, clinically undetectable and would have remained undetected in the neonatal period if they had not been identified prenatally on the maternal ultrasound scan. Opinion remains divided on the rationale for removing asymptomatic, prenatally detected MDKs. The arguments center principally on the perceived magnitude of the risks of hypertension and malignant change in later life.
