[An autopsy case of generalized seizures, myoclonus, blindness and deafness].

We have reported the clinical and autopsy findings in a case with generalized seizures, myoclonus, blindness and deafness which was accompanied by stroke-like episodes. This case was diagnosed as mitochondrial encephalomyopathy, lactic acidosis & stroke-like episodes (MELAS) from these findings. Solitary and continuous lesions of softening were distributed in both hemispheres, more severely in the frontal and occipital poles. These lesions did not correspond to a vascular supply. The pulvinar, lateral and medial geniculate body of the thalamus, cerebellar vermis and dentate nucleus had small lesions of softening. The cortical lesions occurred mainly in layer 4, and the most prominent lesions among them appeared cystic, involving the subcortical white matter, but nerve cells in layer 1 and 2 were preserved. Proliferation of small blood vessels was seen around the softening areas. Electron microscopy revealed increased mitochondria in endothelial cells of these vessels, abnormal dense bodies in skeletal muscle cells and tightly packed mitochondria in choroid plexus epithelial cells. Immunohistochemical study suggested that vimentin positive cells were seen around lesions and proliferated vessels are different from those seen in the intact tissues.