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A Brazilian man with "severe low back pain" recently showed something unusual on a CT scan.
While his back pain resulted from a herniated disc, doctors saw three kidneys on the scan.
The doctors from Hospital do Rim in São Paulo observed “a normal-appearing left kidney and two fused kidneys in the pelvis,” as noted in a May 7 report in The New England Journal of Medicine.
Three kidneys are "relatively uncommon," according to a report the National Kidney Foundation. Discovery is usually accidental because it rarely causes symptoms.
The condition may continue unknown until imaging is performed for another reason, as in this Brazilian patient’s case, according to the NEJM report.
The ureter – a tube carrying urine from the kidney to the urinary bladder – from the left pelvic kidney joined the ureter from the other left kidney just above its entrance to the bladder, the report noted. The ureter from the right pelvic kidney entered the bladder on the right side.
The development of “supernumerary kidneys” is believed to occur as a result of abnormal processes in embryogenesis, or formation of the embryo.