Renal agenesis: spectrum in utero findings.

Three cases of renal agenesis are presented, representing the spectrum of abnormality seen in utero. Severe oligohydramnios was seen in all three cases. In two cases ultrasound demonstrated fetal paraspinal structures resembling kidneys, while in the third no renal shapes were identified. The urinary bladder could not be imaged in any of the cases. Autopsy findings demonstrated that the reniform structures represented only fetal adrenal glands of varying sizes. It is suggested that the examination of the renal tract in severe oligohydramnios should be directed toward the fetal urinary bladder, because the identification of reniform outlines can be misleading.