Fact-sheet: Horseshoe kidney
Updated on 05/21/2025 at 2:34 PM
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Definition
Most common form of kidney fusion anomalies (1/400 to 1/1,000), with a slight male predominance (M/F = 2/1).
In 96% of cases, renal fusion involves the lower poles. The isthmus connecting the two lower poles consists of parenchyma in 85% of cases, and of a thin fibrous band in 15% of cases.
It is most often located anterior to the great vessels, below the origin of the inferior mesenteric artery. The vascular supply defies any systematization, often with multiple arterial pedicles arising from the sub-isthmic aorta and the iliac arteries.
Clinical features
Malformation most often asymptomatic. Only complications and associated lesions occasionally require intervention.
Ultrasound
Preferred in children and young adults due to its non-irradiating nature.
Semiology similar to CT, but sometimes hindered by bowel gas interposition.
CT
Reference examination, but irradiating.
Fusion of the kidneys at their lower pole.
Search for complications:
- hydronephrosis
- renal lithiasis
- neoplastic
- infectious
- post-traumatic
Differential diagnosis
Pelvic kidney
Renal malrotation
Crossed ectopic kidney