Argentine doctors were shocked when they looked into a woman's uterus searching for an orange-size tumour but found something that resembled a giant rock instead.

Surgeons ended up removing a 56-pound tumour from the 54-year-old woman. It was 22 inches across.

'We thought the tumour could be reduced to an orange's size, but it was totally solid.'— Dr. Oscar Lopez

"At first sight, one could see it was going to be a big tumor, but not that big," said Dr. Oscar Lopez, leader of the surgical team that operated on the woman at Gandulfo Hospital in the city of Lomas de Zamora.

"We were totally shocked," Lopez added Thursday in discussing the procedure that was conducted earlier this year.

Stunning perhaps, but not the biggest. News stories and medical reports say that a 303-pound ovarian cyst was removed in 1991 in California, and other growths exceeding 100 pounds have been reported.

A biopsy determined the growth removed at Gandulfo Hospital was a sarcoma, a malignant tumour, and the patient is being monitored by doctors after spending five days in the hospital following the surgery.

The woman, a housewife who prefers to remain anonymous, weighed 343 pounds at the time of the surgery, which lasted four hours and involved eight surgeons — about double the time and staff usually needed.

Lopez said the woman had felt a constant growth in her abdomen for a year and a half, but just thought she was gaining weight.

Finally, she consulted doctors and it was determined she needed surgery, and the tumour was removed a couple of months ago, he said.

Lopez said that before removing tumours, surgeons generally puncture a growth in various places to remove liquid, but in this case the mass remained solid.

"We thought the tumour could be reduced to an orange's size, but it was totally solid," he said.