Ectopic Kidney

  • Etiology:
    — Pronephros – disappears by 5th week, failure of this stage leads to renal agenesis / hypoplasia
    — Mesonephros – regresses by 12th week leaving behind vas / epididymis / seminal vesicles / ejaculatory ducts, failure of this stage leads to renal agenesis / hypoplasia
    — Metanephros – ureteric bud appears, ureteric bud invaginates nephrogenic blastema, renal ascent, failure of this stage leads to renal ectopia
  • Imaging: pelvic kidney, horseshoe kidney, intrathoracic kidney, crossed fused ectopia
  • Clinical: 1/900 births

Cases of Ectopic Kidney

CT of pelvic kidney
Coronal image (above) from a CT with contrast of the abdomen shows a normal appearing kidney in the left renal fossa and the absence of a kidney in the right renal fossa. An axial image from the same exam (below) shows the right kidney to be located in the pelvis.
IVP of pelvic kidney
AP image from the excretory phase of a vintage intravenous pyelogram shows a normal position of the right kidney in the right renal fossa. The left renal fossa is empty and the left kidney can be found in the left pelvis, over the left side of the sacrum.
Angiogram of cross fused renal ectopia
AP image from a selective angiogram injection of the left renal artery shows fusion of the medial aspect of the left kidney, which has crossed the midline, to the medial aspect of the right kidney, causing the right kidney to be displaced laterally. A right hemivertebra is also present just above the T10 vertebral body.