The histopathology of grey matter demyelination in multiple sclerosis.

Multiple sclerosis (MS) is characterized by focal demyelinating lesions in white matter (WM) and grey matter (GM) of the central nervous system. Results of studies using quantitative magnetic resonance imaging techniques indicate that GM MS pathology has a significant impact on clinical symptoms and disability in MS, and may occur partly independently of WM pathology. Subpial cerebral and cerebellar cortexes are predilection sites for demyelination in MS. Significant neuronal and axonal pathology has been detected in GM MS lesions. The pathology of MS lesions is location-dependent; there is less pronounced inflammation in GM lesion areas than in WM lesions. The presence and extent of GM lesions has recently been correlated to meningeal inflammation, and cells infected with the Epstein-Barr virus have been detected in meningeal infiltrates, suggesting a role of meningeal inflammation in cortical lesion pathogenesis.