Electron microscopic and histochemical studies in diffuse sclerosis

Abstract

A cerebral biopsy was performed on a 9 1/2-year-old male with signs and symptoms of a severe, progressive, neurologic disease and hypoadrenocorticalism. Several months later, the child died, and autopsy confirmed the biopsy impression of sudanophilic diffuse sclerosis. Marked atrophy of adrenal cortex was also noted. Histochemical studies on unfixed autopsy material showed increased activity of glutamic and lactic dehydrogenases, and DPNH and TPNH diaphorase in reactive astrocytes. Acid phosphatase activity was marked in the fat-laden macrophages. Electron microscopic examination was performed on biopsy material. Formation of a massive extracellular space had occurred in involved white matter. Inflammatory cells and macrophages were seen within the perivascular and extracellular spaces. Phagocytes varied considerably in their ultrastructural appearance, probably depending on their state of activity and the type of ingested debris. A wide variety of intracytoplasmic inclusions was seen in phagocytes, and these differed in appearance from those seen in reactive astrocytes. Reactive astrocytes and their processes were ubiquitous and could usually be recognized by their increased numbers of mitochondria and their intracytoplasmic fibrils. The cerebral cortex appeared unremarkable except for some inclusions within endothelial cells and lipofuscin deposits within neurons. It is suggested that the marked activity of the glutamic dehydrogenase and DPNH diaphorase in reactive astrocytes may be correlated with increased numbers of mitochondria seen in these cells by electron microscopy. The prominent acid phosphatase activity of macrophages may be related to the presence of lysosomes or "lysosomal material" in these phagocytic cells.