• Images of the entire brain and spinal cord should be done for tumors that may spread to the spinal cord
  (medulloblastoma, ependymoma, intracranial germ cell tumors, pineal tumors, cerebral neuroblastoma
  PNET).
• Bone scans and bone marrow examinations are sometimes done in medulloblastoma because this tumor may
  spread outside the central nervous system, especially to bone and bone marrow.

Endoscopy and Biopsy 
• Tumors of the brain stem, the medulla and the pons (brain stem glioma) may be biopsied. The procedure is
  risky. They cannot be removed surgically (radiation therapy is the standard treatment). Stereotactic needle
  biopsy techniques may enable biopsy to be done when it could have an effect on treatment—for example, if it
  is not certain that a mass in this area is malignant , if the tumor grows outwards and protrudes into the
  ventricles or if there is a need to remove part of the tumor because of pressure symptoms.
• Biopsy of optic tract glioma is not always possible because it is difficult to expose the area surgically.