Abby Lee Miller has been diagnosed with Non-Hodgkin lymphoma just weeks after leaving prison, according to reports.
The Dance Moms star reportedly left the halfway house she's staying at for hospital this week, for what was thought to be a spinal infection.
However, People claims to have confirmed it was actually a cancer diagnosis.
Miller was sentenced in May 2017 to one year and one day in prison, followed by two years of supervised release for bankruptcy fraud.
People quotes Dr Hooman Melamed of the Cedar Sinai Marina Del Rey Hospital as saying Miller would have died if she wasn't hospitalised.
"If we didn't do something, she was going to die. Her blood pressure was bottoming out. She was not doing well," Dr Melamed said.
"We're getting an oncologist involved and we have to figure out what the next steps are as far as chemotherapy or radiation or more spine surgery.
"Depending on the tumour type, depending on the sensitivity of the tumour - it just depends the type but I feel more than yes, she will undergo chemotherapy or radiation."
Miller continued to post on social media during her prison sentence and after moving to the halfway house.
Her most recent post is from five days ago, where she thanks fans for well-wishes and quoted The Pointer Sisters' song 'I'm So Excited'.