Possessing 3 kidneys is a scenario that is one of the rarest in the world with less than 100 such cases ever reported across mainstream medical journals and literature alike. A man from Brazil visited his doctor with the issue of acute pain in the lower back and doctors found to their surprise that this individual had 3 kidneys instead of 2 as normally found in the regular human. This is an extremely rare condition.
Doctors at the Hospital do Rim at Sao Paulo, Brazil, conducted a CT scan for working out the reason behind severe lower back pain afflicting this 38-year-old man. The case report was published on the 6th of May, 2020, in the NEJM (New England Journal of Medicine). The scan clearly revealed that the individual had a slipped disk or herniated disk, a common medical condition where a part of the cushion-esque disk positioned between spinal vertebrae shifted out of position. However, what really caught the attention of the doctors was the fact that this man had a unique anatomical attribute, i.e. three kidneys instead of two for a regular individual. There was a regular-looking kidney to his left and two fused kidneys which were situated in proximity to the pelvis region as per the case report.
The man did not have any kidney problems or similar symptoms and his organs seemed to be functioning properly as well. In usual scenarios, every kidney is linked to the bladder via a duct which is known as the ureter. In the case of this individual, one of the pelvis kidneys was connected directly via the ureter to the bladder. Yet, the ureter of the other pelvis kidney joined the ureter for the regular left-hand side kidney prior to entering the bladder.
A report published in 2013 talks of a similar medical case in The Internet Journal of Radiology. The condition could take place owing to embryonic development issues when a structure that usually forms one kidney, splits into two. Since this condition does not lead to any symptoms, most people do not know about the same until it is accidentally discovered due to non-linked medical tests/procedures as per the NEJM report authors.