From the Guidelines
Subcortical cerebral white matter gliosis refers to the proliferation of glial cells, primarily astrocytes, in the white matter beneath the cerebral cortex, often in response to injury or damage to the brain tissue, as seen in conditions like progressive multifocal leukoencephalopathy (PML) 1. This condition is characterized by an increase in glial cells, which can occur due to various causes including small vessel disease, chronic ischemia, inflammation, demyelinating diseases, or neurodegenerative disorders. Key features of subcortical cerebral white matter gliosis include:
- Hyperintense (bright) areas on T2-weighted and FLAIR sequences on MRI, as noted in the context of distinguishing PML from multiple sclerosis 1
- Clinical significance that depends on the extent, location, and underlying cause of the gliosis
- Symptoms that vary widely based on these factors and can include cognitive impairment, movement disorders, or may be asymptomatic if limited in extent
- Treatment that focuses on addressing the underlying cause rather than the gliosis itself, as the glial proliferation is a reactive process rather than the primary pathology. In the context of PML, early detection and cessation of natalizumab therapy, along with plasma exchange to restore immune function, appear to be associated with a good prognosis 1. However, the presence of subcortical cerebral white matter gliosis should prompt a thorough investigation into its underlying cause to guide appropriate management and improve patient outcomes.
From the Research
Definition of Subcortical Cerebral White Matter Gliosis
- Subcortical cerebral white matter gliosis refers to a nonneoplastic reaction of astrocytes and/or microglial cells in the subcortical white matter of the brain 2.
- This reaction is characterized by hypertrophy and/or proliferation of astrocytes, which can be induced by various factors such as brain insult, inflammation, or degeneration of neural tissue 3, 4.
Characteristics of Subcortical Cerebral White Matter Gliosis
- The extent of gliosis is correlated with the increase in size of astrocytes in white matter, but not with the density of astrocytes or the intensity of glial fibrillary acidic protein (GFAP) staining 3.
- Subcortical cerebral white matter gliosis can be widespread, as seen in amyotrophic lateral sclerosis (ALS), and can have morphological properties of an active process 4.
- Gliosis in the subcortical white matter can also be associated with other conditions, such as multiple sclerosis, where disease-modifying therapies can affect the rate of subcortical gray matter atrophy 5.
Clinical Significance of Subcortical Cerebral White Matter Gliosis
- The presence of subcortical cerebral white matter gliosis can be a nonspecific finding, and its clinical significance depends on the underlying cause and associated parenchymal damage 2.
- In some cases, subcortical cerebral white matter gliosis can be a secondary cause for headaches, such as in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) 6.
- The diagnosis of subcortical cerebral white matter gliosis requires careful evaluation of clinical, neuroimaging, and pathological features, as well as consideration of the patient's medical history and family history 6.