The largest kidney stones most doctors ever get to see is the size of a golf ball.
So surgeons in Hungary were taken aback when they removed a stone the size of a coconut from a man earlier today.
Sandor Sarkadi underwent an abdominal operation in Debrecen, 150 miles east of Budapest, after doctors discovered he had a kidney stone inside him that was 17 centimetres in diameter.
Mr Sardaki was rushed into an operation theatre in the Kenez Gyula Hospital when an X-ray revealed he was carrying around the gigantic lump.
The delicate procedure to remove the stone, which weighed a staggering 2.48lbs, passed without incident.
Kidney stones vary in size. They can be as small as a grain of sand or as large as a golf ball, which makes Mr Sarkadi's stone all the more remarkable.
Most stones pass through the body by themselves within hours or a few days. Doctors advise patients to drink a lot of fluids to help this process, and sometimes recommend a special diet.
Stones of a larger variety have to be surgically removed.