Toronto Mayor Rob Ford underwent CT scans of his abdomen and chest, a biopsy and an ultrasound examination at Mount Sinai hospital Thursday after being admitted to hospital following the discovery of a mass in his abdomen yesterday.

The results of the biopsy, crucial in understanding the nature and extent of the tumour, are not expected for another week.

“We are still in a holding pattern,” said Dr. Zane Cohen, a colorectal surgeon at Mount Sinai Hospital and leader of the clinical team treating Ford.

“Tomorrow we need to do further investigations in the form of an MRI and have a multidisciplinary discussion between different clinical members and then decide on the next steps.”

Cohen declined to speculate on the cause or precise nature of the mass, saying that Mayor Ford was “resting comfortably” and that he was “surrounded by family members.”

Once the biopsy results are in, Cohen said, hospital staff will “be able to talk in facts and not in suppositions."

Doctors are not sure exactly what organ the mass may be growing on, but Cohen said it is a "fair size."

Ford was admitted to hospital yesterday after complaining of "unbearable pain" in his abdomen that has persisted for nearly three months. Cohen said it's not clear when Ford may be able to leave hospital.

While leaving Mount Sinai Hospital Thursday night, the mayor's wife Renata Ford told CBC News her family is "very hopeful" for her husband's quick recovery.

Ford had abdominal surgery in 2009 to remove a tumour on his appendix. His father, Doug Ford Sr., died of colon cancer in 2006 only months after being diagnosed.

Ford's former chief of staff Mark Towhey said Thursday that Ford often described his previous surgery as one of the "worst things he's ever gone through."

Campaign questions

Ford is up for re-election on Oct. 27. His brother and campaign manager, Coun. Doug Ford, has not said how the tumour diagnosis might impact his campaign but called the news "devastating."

As of Thursday afternoon, the mayor's name was still among the registered candidates listed on the city's website and he has until Friday at 2 p.m. to formally withdraw from the race. His name could, in theory, remain on the ballot if he does not withdraw. But that could leave him unable to campaign and possibly unable to fulfill mayoral duties if he were to win the election.

"I just don’t think [Ford's campaign] is going to be in a position to make a decision about taking the mayor’s name off the ballot by 2 o'clock tomorrow, and I don’t see any political upside in doing that for Rob Ford," said Towhey in a phone interview with CBC News Network.

"Unless Doug Ford is going to jump in and run for mayor in Rob’s stead — and I really don’t think that will happen — there's just no benefit for Rob rushing down to take his name off the ballot.”

Towhey added that Ford's hospitalization presents a difficult challenge for other mayoral candidates, who have relied heavily upon criticisms of Ford's ability to serve as a public official, in light of a string of recent scandals and admissions of drug and alcohol abuse.

"The only real issue in this election so far has been Rob Ford. The ballot question has been: 'Rob Ford, yes or no?'," he said.

The other contenders, however, "have been robbed of that because they can't kick him when he's in the hospital."

City hall rivals offer support

Throughout the day many Toronto councillors, even some of his most bitter political rivals, sent well-wishes to the mayor.

Toronto Mayor Rob Ford is 'resting comfortably' in hospital following a biopsy on a mass in his abdomen. (Colin Perkel/The Canadian Press)

"It's a big shock," said Coun. Denzil Minnan-Wong, speaking to the media on Thursday.

"I think we're all sad and concerned about the mayor's health and we hope the news that we're going to hear in the next couple of days is going to be really positive and he's going to get better."

Coun. Joe Mihevc said he was among many who are concerned about the mayor, all politics aside.

"It's a shocker for us all. We thought he was in good health and he was in recovery mode from health issues that he was struggling with," Mihevc said.

"I think, frankly, most all of us in Toronto, our prayers are with him on a personal level."

Joe Maurini, a long-time Ford supporter and campaign volunteer told CBC News he was also "in shock."

"I have tears in my eyes right now. Nobody expected this,” he said outside of Ford's campaign headquarters. “I worked for him from day one, and I still support him. I hope that he’ll come back.”

String of scandals

Throughout his term, Ford has often been at the centre of controversy, but particularly so over the past two years.

Last year, Ford was mired a drug-related scandal that enveloped his office for months and eventually saw him admit to smoking crack cocaine. Council stripped him of some of his powers, but he did not step down despite intense pressure.

There was also a police investigation relating to the so-called crack tape, the recording of Ford using the drug, which the mayor initially denied existed.

This past spring, Ford was photographed holding a crack pipe and, shortly after, he enrolled in a rehab program. He returned to city hall at the end of June.

Ford is up against dozens of candidates in the coming election. But he is one of the top three in the polls, along with Olivia Chow and John Tory.