Rob Ford has been admitted to Humber River Hospital on a "working diagnosis" of an abdominal tumor. Speaking at a press conference earlier this evening, Dr. Rueben Devlin, the president and CEO of the hospital, said Ford was suffering from pain in the lower left quadrant of his abdomen when he entered the emergency department earlier today.

A subsequent CT scan confirmed the presence of a tumor and doctors are conducting a biopsy to determine whether the mass is cancerous, he said.

"We need to determine exactly what type of tumor it is, and then we can decide on what treatment is required," Devlin said. "We hope that we will be able do a lot of that investigation this week ... it wasn't a small tumour, but the size is not as relevant as what it is."

Beyond that, little information is available about Ford's immediate condition. Doug Ford said his brother was complaining of stomach pain earlier this morning. "I had breakfast with him today over at Perkins. He said his stomach was bothering him, he went to the doctors, and then the doctor sent him over to Humber," he said. "He's in good spirits and he just thanks everyone for all the well-wishes."

According to Toronto Sun reporter Don Peat on Twitter, Ford was treated for a tumor on his appendix in 2009. Since becoming mayor, Ford has been hospitalized twice: for kidney stones in 2011 and for a throat problem that aggravated his asthma in 2012.

Ford was absent from city hall today and information on his whereabouts was not made available by his election campaign staff. News of his condition came in a press release from the hospital at 6:18 this evening.

Doug wouldn't say whether his brother was thinking about dropping out of the race.

"If you could just leave us alone, that would be great, for the next couple of days, then we will inform you on what's going on," he said. "I'll speak to you folks probably in the next couple of days."

Chris Bateman is a staff writer at blogTO. Follow him on Twitter at @chrisbateman.

Image: RadarContact/blogTO Flickr pool.