As with many types of tumors, the cause or causes of medulloblastoma are unknown. However, we do know that this cancer is more common in children, and usually appears in the first eight years of life. That said, about one third of all medulloblastoma cases appear in adults between the ages of 20 and 44. This type of tumor appears more often in boys than girls. Children with a hereditary condition known as Gorlin syndrome have a higher risk of developing a medulloblastoma.
Still, this is a rare condition, comprising just 2 percent of all primary brain tumors and 18 percent of childhood brain tumors.