Mr He from Zhejiang Province in eastern China, checked into the Dongyang People's Hospital complaining of intense pain in his abdomen last month. A CT scan revealed that his left kidney was packed full of stones, most of them tiny.
Doctors operated on Friday in an agonising procedure that lasted about two hours. Mr He said he had a history of suffering from kidney stones. Twenty years ago he had 10 stones removed using a procedure called lithotripsy, which sends shock waves to break up stones in the kidney, bladder, or ureter until they are small enough to pass in the urine.
The unusually high number of stones was attributed to the high concentration of gypsum tofu, a popular local food, in Mr He's diet. The tofu contains calcium sulphate, which cannot be expelled from the body without a sufficient intake of water.
Following the operation, Mr He took his stones home with him in a plastic bag.
The medical name for kidney stones is nephrolithiasis. If the stones cause severe pain, this is known as renal colic. Most kidney stones are small enough, between 4 to 5mm in diameter, to be passed naturally.
Kidney stones are quite common and usually affect people aged 30 to 60 years.