Doctors in India who have removed a 1.8kg (3.9lb) brain tumour from a 31-year-old man say it could be the largest in the world.
The surgery, which lasted seven hours, took place on 14 February at the Nair hospital in the western city of Mumbai.
But the procedure was not made public as doctors were not sure until now if it had been successful.
"Now it's a matter of recovery but he's out of danger", Dr Trimurti Nadkarni, chief of neurosurgery, told the BBC.
Santlal Pal, a shopkeeper from the northern state of Uttar Pradesh, had been living with the tumour for three years before his surgery was carried out.
Doctors said Mr Pal had lost his vision because of the tumour but hoped he would regain it as he continued to recover from the operation.
His wife told the Hindu newspaper that they had been told by doctors at three different hospitals in Uttar Pradesh that the tumour was inoperable.
"Such cases are critical", said Dr Nadkarni, adding that Mr Pal needed 11 units of blood during the operation and after that, he was connected to a ventilator for a few days after the surgery.