A supernumerary kidney is an additional kidney to the number usually present in an organism. This often develops as the result of splitting of the nephrogenic
blastema
A blastema (Greek ''βλάστημα'', "offspring") is a mass of cells capable of growth and regeneration into organs or body parts. The changing definition of the word "blastema" has been reviewed by Holland (2021). A broad survey of how blas ...
, or from separate
metanephric blastema
The metanephrogenic blastema or metanephric blastema (or metanephric mesenchyme, or metanephric mesoderm) is one of the two embryological structures that give rise to the kidney, the other being the ureteric bud.
The metanephric blastema mostly de ...
s into which partially or completely reduplicated ureteral stalks enter to form separate capsulated kidneys; in some cases the separation of the reduplicated organ is incomplete (fused supernumerary kidney).
Less than a hundred cases are known of one or two supernumerary kidneys.
See also
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Supernumerary body part
Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs.
Many addition ...
References
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Supernumerary body parts
Nephrology
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