FOCAL TRANSMANTLE DYSPLASIA - A SPECIFIC MALFORMATION OF CORTICAL DEVELOPMENT

We report 18 patients who presented prior to age 20 years with epileps y or fixed neurologic deficits. MRI showed signal abnormality extendin g from the cortex to the superolateral wall of the lateral ventricle. Histology showed cortical disorganization, neuronal cytomegaly, balloo n cells, indistinct cortical gray matter-white matter junctions, and v ariable accompanying astrogliosis. We propose that this transmantle dy splasia is a specific anomaly resulting from abnormal stem cell develo pment.