Head and neck pain is a common warning sign of a brain tumor. Children develop brain cancer at the base of their brain with a form of cancer known as ependymoma. The warning signs of a pediatric brain tumor, such as ependymoma, include head and neck pain of unknown origin, lack of physical activity, loss of appetite, light or sound sensitivity. Simple imaging studies of the brain, such as a CT or MRI of the brain, will detect a brain tumor.