CNS Toxicity

  • Chemotherapy
    • Uni or bilateral periventricular WM restricted diffusion without FLAIR abnormality
      • Acute (< 1 mos)
      • Resolves in 2-3 weeks, FLAIR abnormality appears later
    • Butterfly appearance of corpus callosum
      • Focal cerebral necrosis from intraventricular chemotherapy
      • Diff Dx: GBM, lymphoma
    • Diffuse WM FLAIR hyperintensity (days-weeks after treatment)
      • Induced reversible leukoencephalopathy
    • Cortical and subcortical WM FLAIR hyperintensity
      • PRES (can also involve basal ganglia)
    • Myelopathy in the spinal cord
  • Immunotherapy
    • WM + CC FLAIR hyperintensity, no enhancement
      • Rituximab associated PML
      • DiffDx: HIV encephalopathy
    • Enlargement and enhancement of pituitary stock and gland
      • Ipilimumab (melanoma treatment) induced hypophysitis
      • Returns to normal in 4-6 weeks after steroids
    • EOM enlargement and enhancement
      • Ipilimumab induced ocular myositis
  • Radiotherapy
    • Progressive symmetrical confluent WM FLAIR hyperintensities
    • Scattered microbleeds
    • Radiation induced cavernoma
    • Vasculopathy
    • Gyri form enhancement posteriorly
      • Stroke-Like Migraine Attacks after RT (SMART)
      • 6-30 yrs after RT
    • “Spreading wavefront” or heterogenous lesion enhancement with low CBV on MR perfusion, elevated lipid-lactate peak, decreased metabolites
      • Radiation induced necrosis
    • Mineralizing microangiopathy