Abnormal cytoarchitecture of cortical dysplasia verified by immunohistochemistry

Cortical dysplasia is a broad category for an abnormal structure of the cerebrum due to a disorder of the normal developmental process for neocortex. We investigated the cortical dysplastic lesions which were surgically resected from 4 patients with intractable epilepsy. All cases showed a derangement of the cortical laminar structure and dysplastic changes in the neurons. In addition, 3 of them showed large round cells (balloon cells) in the deep cortex and subcortical white matter. Since each lesion showed slightly different features, we further examined the lesions immunohistochemically by using a panel of antibodies against cytoskeletal proteins to recognize and classify the cortical dysplastic lesions. An immunohistochemical study revealed marked abnormalities of the cytoskeletal structures of dysplastic neurons, bizarre glial cells and balloon cells. These cells showed an accumulation of either phosphorylated NF, MAP2 or GFAP in a distinct fashion. Ubiquitin immunoreactivity highlighted the extent of cortical dysplastic lesions. In a young patient, we also found the neuronal cytoplasmic lipofuscin deposition. It is thus considered that these diverse immunohistochemical appearances of cortical dysplasia may thus imply a different pathogenesis and they should therefore be classified based on the extent of histological abnormalities.