Table 1:

JCV-associated CNS diseases

Types of PMLClinical PresentationImaging AppearanceHistopathology
cPMLFocal neurologic signs depending on the location of lesionsT1 hypointense (to white matter) and T2 hyperintense (to gray matter) lesions in the subcortical U-fiber rather than in periventricular white matter; diffusion restriction at the margin; no enhancementSevere demyelination; swollen oligodendrocytes with enlarged densely basophilic nuclei filled with eosinophilic inclusion bodies; bizarre astrocytes; absent/minimal inflammation
iPMLiPML in IRIS presents with aggravated cPML symptoms; iPML in the non-IRIS setting has similar or aggravated cPML symptomsPeripheral or rim enhancement with or without mass effect and vasogenic edemaSimilar to cPML plus marked inflammatory reaction characterized by diffuse or focal perivascular mononuclear cell (mainly CD3) infiltration
JCVGCNCerebellar symptoms including ataxia and dysarthriaMR findings are negative in early stage; isolated cerebellar atrophy with T2 hyperintensity in later stage of the diseaseIsolated infection of the cerebellar granule cell neurons sparing oligodendrocytes
JCMSimilar to viral meningitisNo specific imaging findingCSF positive for JCV DNA
JCEAbnormal higher CNS function without focal neurologic deficitPredominant cortical T2 hyperintensity with involvement of white matter in later stage of the diseaseExtensive infection of the pyramidal cell neurons with meager infection of oligodendrocytes