what is blood tumor?


Optional Information:
Female , Age: 6

Already Tried:
today a cousin has been told she has blood tumor in her brain (stem area). No one knows anything about it. they will monitor her for 3 months to see if it'll grow or rupture again. It had ruptured and caused damage to her left side, she will need therapy. we want to know everything about blood tumors. Where can i find more info? what are he chances? best treatment? what can we do?