Crossed renal ectopia

Last revised by Yaïr Glick on 8 Feb 2024

Crossed renal ectopia is said to be present when the kidney is seen in the opposite retroperitoneal space. It is more common for the left kidney to be ectopically located on the right side. More than 85% of these get fused resulting in crossed fused renal ectopia. Less than 15% cases are non-fused.

Clinical presentation

Crossed renal ectopia is usually asymptomatic and incidentally found on imaging workup. It is usually seen fixed to iliac crest, but below the level of L2.

Radiographic features


Absent kidney in its respective renal fossa. On careful examination, it is seen on the opposite side in the lumbar or iliac region.


It easily demonstrates the kidney in its ectopic location.  The detail of the collecting system is beautifully illustrated with CT-IVU, which may be important in the planning of surgical procedures.

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