Diagnosis

The process of diagnosis usually starts with a medical history review and a discussion of signs and symptoms. Tests and procedures used to diagnose medulloblastoma include:

• Neurological exam. During this procedure, vision, hearing, balance, coordination and reflexes are tested. This helps determine which part of the brain might be affected by the tumor.
• Imaging tests. Imaging tests can help determine the location and size of the brain tumor. These tests are also very important to identify pressure or blockage of the CSF pathways. A computerized tomography (CT) scan or magnetic resonance imaging (MRI) may be done right away. These tests are often used to diagnose brain tumors. Advanced techniques, such as perfusion MRI and magnetic resonance spectroscopy, also may be used.
• Tissue sample testing (biopsy). A biopsy is usually not done, but it may be recommended if the imaging tests are not typical of medulloblastoma. The sample of suspicious tissue is analyzed in a lab to determine the types of cells.
• Removal of cerebrospinal fluid for testing (lumbar puncture). Also called a spinal tap, this procedure involves inserting a needle between two bones in the lower spine to draw out cerebrospinal fluid from around the spinal cord. The fluid is tested to look for tumor cells or other abnormalities. This test is only done after managing the pressure in the brain or removing the tumor.