HISTOPATHOLOGY OF A FOCAL BRAIN SOFTENING

In this case the changes that have ensued on the occurrence of vascular occlusion are characterized by complete necrosis of the nervous tissues in the center. This occurred much more rapidly in the white than the gray matter where the ganglion cell layers became converted into a structureless mass. The tissue reactions involved both the glia and the mesodermal tissue. In the former, the changes were of two kinds: (1) the development of cytoplasmic glia and gitter cells. These latter infiltrated the whole central region and entered the adventitial sheaths of the vessels where they were surrounded by connective tissue fibrils; (2) at the periphery of the lesion especially, the development of glia fibers. In the smallest lesions these constituted the principal reaction and the final result was a glial scar. The mesodermic reaction included active fibrous proliferation and new vessel formation, with proliferation of lymphocytes. These connective tissue elements had invaded the necrosed area and the central region of softening.