If you or your child have symptoms that may signal medulloblastoma, your doctor will perform an exam and ask questions about overall health. The doctor also may do a neurological exam to test reflexes, muscle strength, vision and other functions of the brain and spine.

If anything appears abnormal, the doctor may refer you to a neurologist, neurosurgeon or neuro-oncologist, doctors who specialize in the treatment of nervous system diseases.

One or more of the following diagnostic tests may be used to find out if you or your child have medulloblastoma and if it has spread. These tests also may be used to find out if treatment is working.

Imaging tests, including:
CT (computed tomography) scans
MRI (magnetic resonance imaging) of the brain and spine
PET (positive emission tomography) scan

Surgery: If an MRI or CT of the brain shows a tumor in the lower part of the back of the brain, medulloblastoma may be a possibility. In an operation called a craniotomy, all or part of the brain tumor is removed. This is needed to confirm the diagnosis and is the first step of treatment. If tumor removal is not possible, a biopsy may be needed. In a biopsy, a small sample is removed from the tumor and looked at with a microscope to confirm the diagnosis.

In addition to tumor removal, additional tests are required to evaluate how much the disease has spread from its original site and decide the best course of treatment. These tests include:

A brain MRI obtained after tumor removal

A whole spine MRI

A spinal tap, or lumbar puncture). During this procedure, a small amount of cerebrospinal fluid (clear liquid in and around the brain and spine) is removed with a needle from the spinal canal. It is then examined with a microscope to determine if tumor cells have spread into the cerebrospinal fluid.

A CT or a PET scan of the body may be needed in some cases to determine if the tumor has spread outside of the nervous system