White matter changes first described in children with leukemia, associated with radiation and chemotherapy injury, often associated with methotrexate; pathologically characterized by diffuse reactive astrocytosis with multiple areas of necrotic foci without inflammation. [leuko- + G. enkephalos, brain, + pathos, suffering]
- progressive multifocal l. (PML) a rare, subacute, afebrile disease characterized by areas of demyelinization surrounded by markedly altered neuroglia, including inclusion bodies in glial cells; it occurs usually in individuals with AIDS, leukemia, lymphoma, or other debilitating diseases, or in those who have been receiving immunosuppressive treatment. Caused by JC virus, a human polyoma virus. SYN: progressive subcortical encephalopathy.
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leu·ko·en·ceph·a·lop·a·thy or chiefly Brit leu·co·en·ceph·a·lop·a·thy -in-.sef-ə-'läp-ə-thē n, pl -thies any of various diseases affecting the brain's white matter esp PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY
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leu·ko·en·ceph·a·lop·a·thy (loo″ko-ən-sef″ə-lopґə-the) any of a group of diseases affecting the white matter of the brain, especially of the cerebral hemispheres, and occurring as a rule in infants and children. The term leukodystrophy is used to denote such disorders due to defect in the formation and maintenance of myelin in infants and children.Medical dictionary. 2011.