Walsh & Hoyt: Pathology

The pathologic findings in VE depend on the form of the disease and the stage at which death occurred. Patients with the rapid form of VE show thickening and clouding of the meninges, which are infiltrated with mononuclear cells and, to a lesser extent, plasma cells and polymorphonuclear leukocytes. The cerebral cortex, basal ganglia, brainstem, and cerebellum are infiltrated by macrophages and microglial cells. Perivascular cuffing with mononuclear cells is widespread. Multiple, fresh, necrotic lesions are distributed throughout the gray matter. These lesions consist of an eosinophilic necrotic mass ringed by an inner layer of mononuclear and microglial cells and an outer layer of reactive astrocytes. In other lesions, considered late necrotic foci, the necrotic core is filled with condensed granular material, surrounded by the inflammatory infiltrate. Neurons are completely destroyed in the area of both types of necrotic lesions. Similar changes are present in the anterior and posterior horns of the spinal cord.