Genitourinary Radiology > Embryology > Migration of the Kidney > Renal Ectopia

Renal Ectopia

  • Renal ectopia

    Arrest or exaggeration of normal caudal-to-cranial ascent of the kidney, resulting in abnormal position.

  • Pelvic kidney

    Premature arrest of cranial ascent of the kidney. There is a 3:2 male-to-female predominance. Most are asymptomatic, but the major complications include trauma (due to decreased protection) and nephrolithiasis (due to altered geometry resulting in urine stasis). Pelvic kidneys are associated with other urinary tract anomalies, including UPJ obstruction, vesicoureteral reflux, and decreased function. Bilateral pelvic kidneys may fuse, forming a discoid single kidney known as a pancake kidney.

  • Contrast enhanced CT of abdomen and pelvis shows normal lower pole of right kidney (RK) but no left kidney in the upper retroperitoneum. Pelvis images shows the left kidney (arrows) which failed to ascend and rests in the pelvis. Delayed images would show that excretion of contrast into the ureter would drain to the normal location at the left UVJ.

    Contrast enhanced CT of the pelvis shows fused right and left kidneys (arrows) which also failed to ascend representing bilateral fused pelvic kidneys also know as "pancake" kidney.

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