US Senator Edward Kennedy has a malignant brain tumour, doctors said today.
Doctors for the Massachusetts Democrat said tests conducted after Mr Kennedy suffered a seizure this weekend show a tumour in his left parietal lobe.
His treatment will be decided after more tests, but the usual course includes combinations of radiation and chemotherapy.
The 76-year-old senator has been in hospital in Boston since Saturday, when he was airlifted from Cape Cod after a seizure at his home.
His wife and children have been with him each day but have made no public statements.
His doctors said in a statement today that he has had no further seizures, is in good spirits and is resting comfortably.