Morphologic variations in periventricular leukomalacia.

Periventricular leukomalacia (PVL) usually is manifested as discrete foci of coagulation necrosis of the deep periventricular white matter in the human neonatal brain. During the examination of the brains of 116 infants utilizing an oil red O technic on gelatin-embedded frozen sections, 25 cases of PVL were found with typical foci of coagultion necrosis. Three morphologic varieties of the lesion could be demonstrated. In the first type, rather than being restricted to the periventricular zone, the discrete necrotic foci extended throughout the entire zone of cerebral white matter, even out to just beneath the cortex. The subcortical lesions appeared of short duration, whereas older lesions were always present nearer the ventricle. The second type of lesion presented as linear, some-what serpentine zones of coagulation necrosis radiating into the cerebral white matter. A third type of lesion consisted of a variegated irregular coagulation necrosis which was poorly delineated from more normal tissue. Diffuse pallor of the white matter, the nature of which is still not clear, was associted with the more severe lesions. Although the pathogenesis of PVL is unknown, it is suggested that these new varieties of PVL beyond the discrete periventricular foci of necrosis would be more apt to result in a diffuse loss of white matter and hence mental retardation if the child should survive.