Former Toronto mayor Rob Ford is in "excruciating pain" and a new tumour has been found on his bladder, brother Doug Ford says.

Ford's medical team at Mount Sinai Hospital discovered the tumour after Ford, 46, was hospitalized for several days last week with abdominal pain, a statement released by his office on Wednesday said. The Etobicoke councillor is at home now, but is expected to return to hospital tomorrow.

"I've never seen him in this much pain," an emotional Doug Ford told CBC News.

Doctors have yet to determine if Ford's tumour is new, or if it's potentially related to the abdominal liposarcoma he was diagnosed with last year.

Thank you everyone for your continued thoughts and prayers, I remain optimistic that I will be able to overcome this setback. —@TorontoRobFord "At this time, we are still awaiting testing results to determine if it is related to the previous growths, as well as whether it is malignant," the statement from Ford's office said.

Ford has been forced to wear track suits at city council meetings while he continues to recover from a major cancer surgery in May. (Chris Young/Canadian Press) Ford will get additional treatments to deal with the tumour, though the statement didn't specify what type.

Ford also tweeted, saying he's "optimistic" he'll recover.

"Councillor Ford and his family wish to extend their continued gratitude for the thoughts, prayers, and support that they have received during this difficult time," the statement said.

Doug Ford said the new tumour came out of left field and was a major blow to his brother's morale.

"It's tough right now," he said.

Councillors saddened by news

At Toronto City Hall, news of Ford's new tumour shocked councillors.

Thoughts are with Councillor <a href="https://twitter.com/TorontoRobFord">@TorontoRobFord</a> and his family during this difficult time. Wishing him all the best. —@JohnTory "He's been through so much and to face another setback so soon has got to be difficult for Rob and his family," said Coun. Denzil Minnan-Wong, who previously served on Ford's executive committee.

Minnan-Wong said Ford had been getting back to his old "fighting form" on council in recent months.

Mayor John Tory tweeted his best wishes to Ford and his family.

Coun. Josh Colle, meanwhile, told reporters the news was "really sad to hear," and added, "I hope he gets past this health scare."

Ford is still recovering from the major surgery he had in May to remove a cancerous tumour in his abdomen. By July, he was cleared to return to work, but he still has to wear track suits as his body recovers.

Ford's cancer caused him to drop out of last year's mayoral race, which was won by John Tory.