Bolsonaro's lawyers are likely to put his ill health forward as an argument for house arrest rather than prison following his coup conviction.
Doctors for Brazil's former President Jair Bolsonaro said on Wednesday that they have detected early-stage cancer in skin lesions removed from the 70-year-old politician following his conviction last week on attempted coup charges.
Bolsonaro, under house arrest in Brasilia until his sentence is finalised, has been to hospital twice since Thursday's court verdict.
He went to the DF Star hospital on Sunday to have eight lesions removed for testing and again on Tuesday because of vomiting and low blood pressure before being released on Wednesday.
Results showed early-stage skin cancer in two of the lesions, doctors said in a statement, adding that Bolsonaro will need clinical monitoring and regular re-evaluation.
"My father has already fought tougher battles and won. This one won't be any different," Bolsonaro’s eldest son Flávio said on a post on X.
"You can be sure that this is the result of the relentless persecution ever since Jair Bolsonaro dared to challenge the system head-on and fight for Brazil."
A panel of Supreme Court justices on Thursday found the former leader guilty of attempting a coup to illegally hang onto power following his 2022 election defeat to current President Luiz Inácio Lula da Silva.
They sentenced him to 27 years and three months in prison.
The sentence doesn't immediately send Bolsonaro to prison. The court panel has up to 60 days to publish the ruling after the decision. Once it does, Bolsonaro's lawyers have five days to file motions for clarification.
His lawyers are expected to put his ill health forward as an argument in a plea for house arrest, rather than obliging him to serve the sentence in a detention centre.
Bolsonaro has denied any wrongdoing and said he is the victim of political persecution. US President Donald Trump has agreed and called the trial a "witch hunt" and in July he imposed tariffs of 50% on Brazilian goods, citing the case against Bolsonaro, among other issues.
Since early August, Bolsonaro has been under house arrest imposed by the justice overseeing the case, Alexandre de Moraes, who said he had violated precautionary measures imposed on him in context of the trial.
Bolsonaro had already been wearing an ankle monitor, a measure enforced after Federal Police said that he and his lawmaker son Eduardo had been working with US authorities to obtain sanctions against Brazilian public officials due to alleged persecution.
In late August, de Moraes increased security measures further and ordered that police conduct inspections of all vehicles leaving Bolsonaro’s residence and monitor the exterior of the house.
Bolsonaro has been hospitalised multiple times since being stabbed at a campaign event before the 2018 presidential election. In April, he underwent surgery for a bowel obstruction.