Intranuclear inclusions of oligodendrocytes are seen in -

Progressive Multifocal Leucoencephalopathy Progressive multifocal leucoencephalopathy (PML) is a slow viral infection of the CNS caused by a papovavirus called JC virus (not to be confused with CJ disease or mad-cow disease; JC virus here stands for the initials of the patient first infected). PML develops in immunocompromised individual like CMV and Toxoplasma encephalitis does, and is, therefore, an impoant form of encephalitis due to increasing number of cases of AIDS. PML infects oligodendrocytes and causes progressive demyelination at multifocal areas scattered throughout the CNS. Grossly, the lesions consist of focal, irregular gelatinous areas most prominent at the junction of grey and white matter. Main areas affected are cerebrum, brainstem, cerebellum, and sometimes spinal cord. Microscopically, the features are as under: Focal areas of demyelination. Many lipid-laden macrophages in the centre of foci. Enlarged oligodendroglial nuclei containing purple viral inclusions at the periphery of the lesion. Ref:TEXTBOOK OF PATHOLOGY 6th EDITION - HARSH MOHAN PAGE NO:878