Progressive multifocal leukoencephalopathy (PML)

Case contributed by Dr Maxime St-Amant


Known HIV+ patient with altered mental state.

Patient Data

Age: 40 years
Gender: Male

Non-specific findings of juxtacortical (subcortical U-fibers) white matter T2/FLAIR hyperintensities involving the precentral gyri at the upper convexity. There are similar hyperintensities in the right thalamic/posterior arm of the internal capsule. 

Case Discussion

These findings are non-specific, but in an HIV+ patient, PML is not excluded. The main differential diagnosis would be HIV encephalitisCMV encephalitis, IRIS (Immune Reconstitution Inflammatory Syndrome), ADEM & multiple sclerosis.

This case is atypical as the findings are not as extensive as expected in PML. The patient died a few months later. This patient had a prior brain biopsy which confirmed JC virus-infected oligodendrocytes with enlarged amphophilic nuclei located at the periphery of the lesions.

Other pathologic findings include :

  • reactive gliosis with enlarged astrocytes
  • macrophages containing phagocytosed cellular debris and myelin​​
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Case information

rID: 19175
Published: 12th Aug 2012
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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