May 12, 2011 -- Television icon Mary Tyler Moore is undergoing surgery today to remove a tumor from the protective lining around her brain.
"At the recommendation of her neurologist, who has been monitoring this for years, and a neurosurgeon, Mary decided to proceed with this fairly routine procedure," said a representative.
The elective procedure is to remove a meningioma, a benign tumor growing on the meninges, the protective layer of tissue between the brain and skull.
"Mary went in for an elective surgery that her doctor recommended while she's healthy," said spokeswoman Alla Plotkin.
Meningiomas are slow-growing tumors that are often benign and which doctors typically leave alone, said Dr. Alan Cohen, chief of surgery at Rainbow Babies and Children's Hospital in Cleveland.
Surgery is necessary, however, "for two reasons," he said, "first, to find out exactly what it is pathologically, and, second, to relieve pressure."
Dr. Cohen has never treated or examined Moore and cautioned that an early diagnosis can change after a tumor has been surgically removed and examined.
A large meningioma tumor could eventually become cancerous, but even if it remains benign, it can create pressure on the brain, resulting in vision or hearing loss, headaches, seizures or other problems.
Meningioma tumors are most frequently found in older women, according to the Mayo Clinic.
Moore, 74, was diagnosed with Type 1 diabetes, formerly called juvenile diabetes, when was 33 and starring on "The Mary Tyler Moore Show."
She appeared today on the "Rachael Ray Show" with former co-star Dick van Dyke. She looked hale and fit, masking the effect diabetes has had on her eyesight and other parts of her body.
The show was videotaped May 5.
Moore has long been an advocate for diabetes and stem cell research. She is the chairwoman of Juvenile Diabetes Research International.