The hospital where veteran Democratic Sen. Edward Kennedy has been recuperating following a seizure revealed today that the Massachusetts lawmaker has a malignant brain tumor.

Kennedy, 76, was airlifted to Massachusetts General Hospital (MGH) in Boston from his home in Hyannis Port on Cape Cod Saturday after suffering a seizure. In a joint statement, MGH neurologist Lee Schwamm and primary care physician Larry Ronan said that a biopsy uncovered a malignant glioma in the left parietal lobe—at the upper rear of the senator's brain.

"The usual course of treatment includes combinations of various forms of radiation and chemotherapy," the statement says. "Decisions regarding the best course of treatment for Senator Kennedy will be determined after further testing and analysis."

According to The Washington Post, doctors initially believed that Kennedy's seizure may have been related to a stroke, but that theory was quickly ruled out. The physicians noted in their statement that some of the tests were inconclusive—in part because of surgery six months ago to unclog the left carotid artery in his neck, where blockage was hindering blood flow to his brain. They also reported that he had not suffered more seizures.

A JAMA The Journal of the American Medical Association study in Feb. 2005 reported that more than 9,000 malignant gliomas are diagnosed annually in the U.S. and that this type of tumor is the second most common cause of cancer-related deaths in people aged 15 to 44. Those with moderately severe tumors typically survive for three to five years, whereas those with severe forms on average live for less than a year. The normal course of treatment for malignant gliomas is a combo of chemotherapy—specifically the drug temozolomide (sold as Temodar)—and radiation. If operable, though, this treatment course follows surgery to remove the tumor.

A glioma is a tumor made up of the brain's glia—cells that support, nourish and protect nerve cells (neurons). Kennedy's glioma is in his left parietal lobe, which integrates information from each of the senses. Damage to this section of the brain can result in a condition known as Gerstmann's syndrome. According to the National Institute of Neurological Disorders and Stroke, sufferers of the syndrome show four primary symptoms: writing disability, impaired ability to perform and understand arithmetic calculations, and the inability to distinguish right from left as well as the fingers on their own hands.

Ted Kennedy is the youngest brother of former Pres. John F. Kennedy and former New York Sen. Robert F. Kennedy. He has served as a senator from Massachusetts for nearly 46 years. His son, Patrick Kennedy, is a House Democrat from Rhode Island who ironically introduced legislation two weeks ago to speed up the development of therapies for brain ailments.

Sen. Arlen Specter, who was diagnosed with a brain tumor in 1993, as well as with Hodgkin's disease in 2005 (that recurred last month)--and wrote a book this year about his fight with cancer called Never Give In: Battling Cancer in the Senate--spoke about the diagnosis on the Senate floor today. The Pennsylvania Republican said: "Senator Kennedy is a real fighter. We all know that. I'm betting on Senator Kennedy."