A 30-year-old man from Huangshi, Hubei Province, was told that he had four kidneys after seeking treatment for his kidney stones, people.com.cn reported on Tuesday.

The man surnamed Chen went to a clinic in Wuhan in September and was told that he had a pea-sized stone in his right ureter.

After further examination in a hospital in Daye, doctors found that Chen has four kidneys, all of which function normally.

"I had no idea I had so many kidneys," Chen said.

Since 1956, when the first case of a person with more than two kidneys was recorded in the world, there have been about 100 people who have had several kidneys. Foreign experts reported four such cases between 1970 and 2002.

These people were born with multiple kidneys, which often go unnoticed until adulthood. Such patients often have no obvious symptoms and are mainly middle-aged women.

people.com.cn