The cortical form of subacute necrotizing encephalopathy of the Leigh type. A light- and electron-microscopic study.

The present paper is a clinico-pathological study of a 14-year-old boy with a chronic, progressive occipital syndrome for which he was operated upon. Postoperatively, metabolic acidosis developed. Pathological anatomy revealed spongy necrosis of the thalamus and corpora quadrigemina with the typical histological features of Leigh's necrotizing encephalopathy. Similar necrotic lesions had developed in the occipital cortex. At this level apart from the typical foci, cavitating necrosis was found as well as involvement of the smaller vessels of the pial circulation. Electron microscopy revealed vascular and glial changes suggestive of primary mesenchymoglial dystrophy. The histiocytes presented intracytoplasmic multiplication of lysosomes and their transformation into lipofuscin pigment. The changes demonstrate a juvenile cortical form of Leigh's subacute necrotizing encephalopathy.