1. Prefinal

2.   Renal agenesis  Renal hypoplasia  Renal fusion  Ectopic kidney  Ureteral atresia  Duplication of the ureter  Supernumerary kidneys Topics

3.   Virtually always unilateral.  Kidney is either absent or undeveloped.  Usually causes no symptoms and found incidentally. Renal agenesis

4.  Renal Agenesis

5.   May appear as one small kidney with the other one larger than normal.  Small kidneys also have small arteries and are associated with hypertension requiring nephrectomy. Renal hypoplasia

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7.   Prevalence 1 in 1,000 people.  Most frequent abnormality seen is a horseshoe kidney containing 2 excretory systems and 2 ureters.  Usually asymptomatic but are prone to obstruction. Renal fusion (horseshoe kidney)

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9.   In simple ectopy, the kidney does not ascend properly and is found in the pelvis or over the brim.  Prone to obstruction and infection.  Less commonly crossed ectopy without fusion. The kidney then lies on the opposite side and is not attached to the normally placed kidney. Ectopic (Pelvis Kidney)

10.  Ectopic Kidney (Pelvis Kidney)

11.   The ureter may be absent or fails to extend to the bladder and therefore with a blind ending.  It is associated with ipsilateral absent or multicystic kidney.  Bilateral atresia is incompatible with life. Unilateral atresia is usually asymptomatic but may cause hypertension. Ureteral atresia

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13.   One of the most common congenital malformations of the urinary tract with duplication found in 0.9% of a series of autopsies.  More common in females and is often bilateral.  Often asymptomatic but commonly presents with persistent or recurrent urinary tract infections. Duplication of the ureter

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15.   Third kidney is very rare and not to be confused with the relatively common unilateral duplication of the renal pelvis. Supernumerary kidneys

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