Central Nervous System
Inclusion body in oligodendroglia is a feature of which of the following?(AIIMS Nov 2014)
|A||Progressive Multifocal Leucoencephalopathy|
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system that results From infection of oligodendrocytes by the JC'polyomavirus.'It occurs almost exclusively in immunocompromised individuals as in HIV due to reactivation of the virus.
Microscopic examination shows lesions in the white matter which is an area of demyelination, in the centel of which are scattered lipid-pladen macrophages and a reduced number of axons. At the edge of the lesion are greatly enlarged oligodendrocyte nuclei whose chromatin,' is replaced by glassy amphophilic. viral inclusion.....Robbins
Significance of microscopic findings in PML
ln PML, the virus also infects astrocytes, leading to bizarre giant forms with irregular, hyperchromatic, sometimes multiple nuclei that can be mistaken for tumor.
In acute cases of Polio there is mononuclear cell perivascular cuffs and neuronophagia of the anterior horn motor neurons of the spinal cord.
ln CJD, ,microscopically, there is characteristic sponglform change in the gray matter ("cluster of grapes vacuolation) without infarction.