Progressive multifocal leukoencephalopathy PML

• Facts:
  Opportunistic infection seen in immunocompromised patients
  Caused by the JC virus (polymavirus)
  Predominantly involves the cortical white matter
• History / PE:
  Hemiparesis
  Disturbances in speech, vision, and gait
  Cranial nerve deficits
  
• Diagnosis:
  Multiple, demyelinating, non enhancing lesions with no mass effects
• Treatment:
  No effective treatment
  Survival form time of diagnosis is 6 months
• Differential Diagnosis:
  Toxoplasmosis (ring enhancing lesion)
  CNS lymphoma (EBV DNA in CSF, weakly enhancing lesions)