ABSTRACT
It is now more than 30 years since cases of antenatally detected multicystic dysplastic kidney (MCDK) were first reported in the literature. MCDK is almost invariably associated with the presence of an atretic segment in the proximal ureter. Nevertheless, it can occasionally occur in conjunction with ureteral dilatation and an obstructive ureterocele. The ultrasound features that characterize MCDKs are now widely accepted and well defined in the radiological literature. When the diagnostic criteria are applied correctly, the sensitivity of ultrasonography for the diagnosis of MCDK is extremely high. It has been argued that the predictive value of ultrasonography is now so high that it is no longer necessary to perform isotope renography to confirm the diagnosis. Opinion is divided on whether it is necessary to perform this invasive investigation routinely if the urinary tract appears otherwise normal on ultrasound. Although the overwhelming majority of prenatally detected MCDKs are asymptomatic and clinically undetectable, some surgeons continue to practice "prophylactic" nephrectomy.
