PMC6417347_01
Magnetic resonance imaging and intraoperative findings in progressive multifocal leukoencephalopathy. (a) A T2-weighted axial image showing multiple convoluted irregular cortical and subcortical lesions in bilateral frontal and parietal lobes. (b) A T2-weighted axial image showing small irregular high signal in the left thalamus. (c) An enhanced T1-weighted axial image showing irregular marginal subcortical enhancement in multiple frontal lesions. (d) An intraoperative photograph taken after removal of a portion of middle frontal gyrus for brain biopsy. The subcortical white matter and surrounding gyri seem normal in gross inspection
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F1
Magnetic resonance imaging (MRI) of the brain revealed multiple confluent subcortical lesions with high signal intensity on T2-weighted image, involving bilateral frontal, right temporal and parietal lobes, and left thalamic and subcapsular regions [Figure 1a and b]. Irregular marginal enhancement on gadolinium was evident [Figure 1c]. Portions of the middle frontal gyrus and subcortical white matter showing enhancement on MRI were taken for pathologic examination [Figure 1d].
Histopathologic examination of progressive multifocal leukoenecephalopathy. (a) Several large infected oligodendrocytes (arrows) with inclusion-bearing dark nuclei or clear nucleoplasm having marginated chromatin (H and E, x400). b) Small round demyelinated lesions with myelin breakdown (luxol-fast blue, x100). (c) High Ki-67 proliferative oligodendrocytes (immunohistochemistry, x200). (d) Viral particles measuring up to 40 nm spheres (EM, x80,000)
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F2
Several large infected oligodendrocytes with inclusion-bearing dark nuclei or clear nucleoplasm having marginated chromatin were present in the periphery of demyelinated area [Figure 2a]. The demyelinated areas revealed small round lesions with myelin breakdown in the luxol-fast blue staining for myelin [Figure 2b]. The hyperchromatic, inclusion-bearing oligodendrocytes displayed high ki-67 proliferative index [Figure 2c] and intense p53 nuclear immunostaining. Electron microscopy revealed infected oligodendrocytes filled by viral particles evident as spheres measuring up to 40 nm in diameter [Figure 2d].