Inclusion bodies in cerebral cortical astrocytes: a new change of astrocytes.

A unique pathological finding of astrocytes was observed in the brain of a 20-year-old man who had severe physical and mental retardation. The brain was malformed showing micropolygyria in several cortical areas. A large number of hypertrophic astrocytes with eosinophilic granular substances in their cytoplasm were found throughout the cerebral cortex. Several staining procedures and electron microscopical examinations were carried out on these intracytoplasmic inclusion. It was found that the appearance and staining character of these inclusions were different from other astrocytic changes, especially the Rosenthal fiber, described so far. The authors consider that these inclusion bodies in cerebral cortical astrocytes represent new pathological changes of astrocytes that appear to be associated with malformation of the brain.