Hyaline astrocytic inclusions in pediatric epilepsy: report of two cases.

Distinctive hyaline inclusion bodies in the cytoplasm of neocortical astrocytes were observed in surgical resection specimens of a frontal epileptic focus, in 2 patients aged 16 and 10 who had suffered intractable partial seizures since the age of 2 years. One case had minimal neurological impairment and no brain malformation on MRI and recovered completely following surgery. The second case had mental retardation and surgery reduced the frequency and generalization of seizures. In both cases, the astrocytic inclusions were strongly eosinophilic, hyaline and refractile. They were PAS negative. Electron microscopy in the first case, confirmed their granular osmiophilic structure. By immunohistochemistry, the inclusions were strongly positive for filamin in the first case, only some were weakly positive in the second case. They also variably expressed other proteins such as alpha-B-crystallin, GFAP, S-100 protein and cytoglobin. We compare our findings with previously reported cases and discuss the clinical significance of the inclusions and the pathophysiologic relevance of filamin A and other proteins accumulation in astrocytes.