SUBLOBAR DYSPLASIA - A NEW MALFORMATION OF CORTICAL DEVELOPMENT

We investigated the clinical presentations and neuroimaging characteri stics of five patients with sublobar dysplasia, an unusual malformatio n of cortical development. Records and teaching files of five unrelate d patients with a localized dysplasia of the cerebral hemisphere separ ated from the remainder of the affected lobe or hemisphere by a deep i nfolding of cortex (sublobar dysplasia) were retrospectively reviewed with regard to age at clinical presentation, manner of clinical presen tation, neurologic examination, location of dysplasia, imaging charact eristics, and the presence and type of associated malformations. Four of five patients presented with seizures; the fifth presented with a c alvarial anomaly. All were neurologically and developmentally normal. MRI showed that the areas of sublobar dysplasia were frontal in two pa tients and temporal, parietal, and occipital in one patient each. The cortex in the affected region of brain was thickened with shallow sulc i and an abnormal sulcal pattern in all affected patients. in three pa tients, the cortical-white matter junction was irregular. The ipsilate ral lateral ventricle was dysplastic in all patients. Associated anoma lies included callosal anomalies (five patients), cerebellar vermian h ypoplasia (three patients), and venous malformation (one patient). Sub lobar dysplasia appears to be a distinct cortical malformation of unkn own etiology that causes no neurologic deficits but ultimately results in epilepsy. Possible causes include abnormal stem cell proliferation and in utero injury.