One in 60 older people may be walking around with benign brain tumors and don't know it. Even more may have bulging blood vessels in the head that could burst.These results come from a surprising new Dutch study that finds brain abnormalities are not all that uncommon.It's not clear how alarming this is. Most of the abnormalities hadn't caused any symptoms, though some were potentially life-threatening.But the findings may have implications for patients in the future: As more of these abnormalities are spotted with more sophisticated equipment during routine medical tests, some doctors may urge patients to have surgery or …