RÉSUMÉ
BACKGROUND: Neuronal migration disorder (NMD) is one of the causes of medically intractable epilepsy. As neurosurgical treatments for medically intractable epilepsy have expanded recently, precise histopathologic diagnosis is required. Histopathologic grading of NMD is important due to its association with neocortical development and expectation of prognosis. Many studies revealed abnormalities of neuronal cytoskeletal protein in abnormal neuronal cells of NMD. METHODS: We performed immunohistochemical staining for neurofilament protein (NF) subtypes, one of the neuronal cytoskeletal proteins, and investigated the staining pattern of specific cells in each grade of NMD. RESULTS: NF-L was more intensely labeled in perikarya, dendrites, and axons of normal or small sized dysplastic neurons, cytomegalic neurons, and balloon cells than of normal-looking neurons. Furthermore, positive reaction was more intense in high-grade lesion. NF-H and NF-M were mainly positive in the axons of gray and white matter and weakly positive in a few cytomegalic neurons and some balloon cells. CONCLUSION: NF-L is a better marker than NF-H and NF-M for the detection of normal or small sized dysplastic neurons, cytomegalic neurons, and balloon cells and for grading of NMD.