Inclusions in oligodendrogliocytes is a feature of -

Progressive multifocal leukoencephalopathy: - Progressive multifocal leukoencephalopathy is a progressive disorder cause by J.C. virus  The main cells affected in the disease are oligodendrocytes. Since oligodendrocytes are concerned with myelination, progressive multifocal leukoencephalopathy is characterized by multifocal areas of demyelination of varying size distributed throughout the brain but sparing the spinal cord and optic nerves. Pathology Besides demyelination there are characterises cytological alterations in both astrocytes and oligodendrocytes: - Astrocytes  Enlarged and contain, hyperchromatic, deformed and bizarre nuclei and frequent mitotic figures. Oligodendrocytes These have enlarged densely staining nuclei that contains virus inclusions formed by crystalline arrays. Symptoms of progressive multifocal leukoencephalopathy: - Visual defects (45%) → Homonymous hemianopia, Conjugate gaze abnormalities Mental impairment (38%) → Dementia, confusion, personality changes Weakness → Hemi or monoparesis and ataxia Seizures (20%) → Speech defect aphasia, hemiparesis, ataxia Focal neurological signs Progressive multifocal leukoencephalopathy is predominantly seen in patients with immunosuppressive disorders Most commonly associated conditions are: - AIDS (80%)Q Hematological malignancies (13%) Transplant recipients (5%) Chronic inflammatory disease (2%) Prognosis of progressive multifocal leukoencephalopathy In most cases, death occurs in 3-6 months from onset of neurological symptoms and even more rapidly in patients with AIDS unless aggressive interetruvial treatment is undertaken. Diagnosis MRI is used for the diagnosis of PML. MRI is better than CT scan in the diagnosis of PML and is frequently used for the diagnosis of PML. On MRI the lesion appears as multifocal asymmetric coalescing white matter located periventricular. These lesions have increased signals on T2 and FLAIR images and decrease signal on T-weighted images. PML lesions are classically nonenhancingQ. Another important diagnostic tool in PML is the PCR ampli