Instead of the usual two kidneys seen in a typical person, the man had three: a normal-looking kidney on his left side and two fused kidneys located near the pelvis, the report said.The man didn't have any symptoms of a kidney problem, and the organs appeared to be working normally.Usually, each kidney is connected to the bladder through a single duct called a ureter. In the man's case, one of the pelvis kidneys was directly connected to the bladder via a ureter. However, the ureter of the other pelvis kidney joined the ureter of the normal, left-side kidney before it entered the bladder.Having three kidneys is rare, with fewer than 100 cases reported in the medical literature, according to a 2013 report of a similar case published in The Internet Journal of Radiology. The condition is thought to arise during embryonic development, when a structure that typically forms a single kidney splits in two.
The supernumerary kidney has a horseshoe component, described in detail here.