Urology Textbook
Clinical Essentials
By Dirk Manski, MD

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Supernumerary Kidney

Definition of a Supernumerary Kidney

A supernumerary kidney is a rare additional kidney with renal function, separate blood supply, organ capsule, and pyelocalyceal system. Next to the supernumerary kidney, there are two normal kidneys. The supernumerary kidney shares the ureter and ostium of the normal ipsilateral kidney in 50%.

Epidemiology

Rare, only case reports available (Bernik et al., 2001).

Etiology:

The cause is an abnormal division of the nephrogenic cord or two separate ureteric buds with separate induction of the metanephric tissue.

Sign and Symptoms

The supernumerary kidney may cause abdominal pain, fever, tumor, or arterial hypertension.

Diagnosis:

If ultrasound raises suspicion of a supernumerary kidney, the diagnosis and the associated anatomy are usually confirmed by CT or MRI.

Treatment of a Supernumerary Kidney

In cases of an asymptomatic supernumerary kidney, treatment is usually not required, although occasional imaging follow-up is advisable. Surgical removal is indicated in the presence of symptoms, complications, or suspected malignancy.






Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


References

Bernik u.a. 2001 BERNIK, T. R. ; RAVNIC, D. J. ; BERNIK, S. F. ; WALLACK, M. K.: Ectopic supernumerary kidney, a cause of para-aortic mass: case report and review.
In: Am Surg
67 (2001), Nr. 7, S. 657–9

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