This is a multicystic dysplastic kidney. This condition must be distinguished from RPKD because it occurs only sporadically and not with a defined inheritance pattern, though it is more common than RPKD. The cysts are larger and variably sized. Often, it is unilateral. If bilateral, it is often asymmetric. If bilateral, oligohydramnios and its complications can ensue, just as with RPKD.