(CNN) Taylor Swift has shared a sad update about her mother's battle with cancer.

In a cover story with Variety released on Tuesday, the singer said that a brain tumor was discovered during her mother's course of treatment.

"The symptoms of what a person goes through when they have a brain tumor is nothing like what we've ever been through with her cancer before," Swift said. "So it's just been a really hard time for us as a family."

The superstar revealed Andrea Swift's cancer diagnosis in an essay she wrote for Elle magazine last March.

"Both of my parents have had cancer, and my mom is now fighting her battle with it again," the younger Swift wrote. "It's taught me that there are real problems and then there's everything else. My mom's cancer is a real problem."

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