What are some possible symptoms of brain cancer in teens?

Many: Balance disturbance, gait changes, vision changes, new onset headache , personality , mood changes, memor changes, unexplaunable decline in behavior or school performance all warrant evaluation

Many possibilities: I am very reluctant to suggest a list of symptoms that are associated with any disease, including a brain tumor. Although the use of warning symptoms and signs has its place in medicine, it is not a very helpful approach for brain tumors--since so many of the symptoms are more commonly associated with other causes. I would suggest you discuss any specific concerns with your teenager's doctor.