Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Progressive multifocal leukoencephalopathy
Medically reviewed by Min Clinic Staff | Updated: January 2026
Progressive multifocal leukoencephalopathy: A rapidly progressive, often fatal viral infection of the brain. Commonly abbreviated as PML.
PML is believed to be due to the Jacob-Creutzfeldt (JC) papovavirus. The virus infects oligodendrocytes (support cells in the brain).
The signs and symptoms of PML include headaches, memory loss, changes in mental status, speech and vision difficulties, loss of strength, limb weakness, seizures, partial paralysis and loss of coordination. The disease leads to coma and then to death.