Laminar scars in cerebral white matter: a perinatal injury due to edema.

Branched plate-like demyelinated lesions were present in the gyral and central white matter of two individuals, 3 and 54 years of age. The degenerated areas contained very few axons and were densely gliotic, and in the older case, contained connective tissue fibers and were continuous with a large parenchymal cyst. The lesions were covered on both sides by normally myelinated white matter, often representing only the subcortical arcuate white matter, occasionally being considerably broader. In some of the latter zones, there was a central area of less severe degeneration which, however, spared the arcuate zone which remained normal. It is suggested that these lesions represent the effects of edema induced by birth injury, under circumstances which permitted the continued formation and maturation of white matter after the edema had subsided. The edema is thought due for the most part to diffuse hypoxia and acidosis, but other mechanisms, such as infection, venous stasis and trauma, may have contributed to the pathogenesis of the edema, and to the lesions directly.