Story highlights Actress Kate Walsh of "Grey's Anatomy" was diagnosed with a benign brain tumor in 2015

Meningiomas are mostly slow-growing, benign tumors that affect women more often than men

(CNN) Actress Kate Walsh, best known for her role in the TV series "Grey's Anatomy," went public on Monday with a brain tumor diagnosis in 2015.

"I was shocked," Walsh said of the moment doctors revealed her MRI results. "It was not what I expected."

Walsh was diagnosed with a meningioma: a tumor arising from the lining that surrounds the brain and spinal cord. Within three days, she underwent surgery to have it removed at Cedars-Sinai Medical Center in Los Angeles. After removing the tumor, doctors confirmed that it was benign.

In January 2015, Walsh initially wrote off symptoms as exhaustion, having just executive produced and starred in the NBC series "Bad Judge."

"I could drink five cups of coffee and not wake up," she said.