White matter

What it is

White matter is the part of the brain composed of myelinated nerve fibers (axons) — the "wiring" that connects different brain regions. Its pale, myelin-rich appearance gives it the name. Diffuse gliomas often spread through the white matter.

Understanding White matter

White matter forms the connections between different areas of gray matter, allowing brain regions to communicate. Because diffuse gliomas infiltrate along these fiber pathways, the white matter is a common route through which they spread — sometimes extending along tracts to distant parts of the brain, or crossing to the other hemisphere (for example, through the corpus callosum). This infiltrative spread through white matter is part of why diffuse gliomas are hard to remove completely. Specialized imaging (diffusion tensor imaging, or tractography) can map white matter tracts to help surgeons plan how to remove a tumor while preserving important connections. Understanding white matter clarifies how diffuse gliomas spread and why preserving these pathways matters in treatment. Understanding white matter clarifies a key route of glioma spread.

Why it matters

Understanding white matter helps patients and families see how diffuse gliomas spread through the brain's wiring — and why mapping these pathways helps surgeons remove tumor while preserving important connections.