Miller, who was released on Friday from a federal reentry center after serving most of a 366-day sentence for bankruptcy fraud, was diagnosed with non-Hodgkin's lymphoma last month, according to People magazine, which also reported she needed emergency spinal surgery.
In an Instagram post this weekend, Miller confirmed that report.
"Now I have to handle the aftermath/ treatment/ physical rehabilitation of 10 hour emergency spine surgery to remove a mass from strangling my spinal cord and the horrible severity of what that mass turned out to be!" she wrote.
Two days later, she posted again, this time appearing in a photo in a hospital room, where she was joined by JoJo Siwa, who appeared on "Dance Moms" with Miller and is now a singer and Nickelodeon star.
"So glad @itsjojosiwa came to visit me today! The whole fam was there to wish me well! Thank you to the Siwa Family for all the beautiful gifts and real popcorn from the movie theater too!" she wrote.
Siwa posted similar photos the same day, including one of Miller holding an oversized check for $10,000.
"When I went to visit Abby I gave her lots of surprises, But the best surprise there was happened with the help of @imadanceragainstcancer. We gave Abby a donation of $10,000!" Siwa wrote.
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