Schizencephaly: clinical and imaging features in 30 infantile cases

Schizencephaly is an uncommon structural disorder of cerebral cortical deve lopment, characterized by congenital clefts spanning the cerebral hemispher es from the pial surface to the lateral ventricles and lined by cortical gr ay matter. Either an antenatal environmental incident or a genetic origin c ould be responsible for this lesion which occurs between the third and four th month of gestation. We report the clinical and cranial imaging features of 30 children, of whom 15 had unilateral and 15 had bilateral lesions. The ir ages at the time of the first presentation ranged from 1 month to 10 yea rs. They were thoroughly studied from clinical, epileptical, imaging and el ectroencephalographic (EEG) viewpoints. Five patients were investigated by cranial computed tomography (CT), eight by cranial magnetic resonance (MR) imaging, and 17 by both methods. The clinical features consisted of mild he miparesis in 17 cases (57%). 12/17 were related to a unilateral phenotype ( 80% of all unilateral forms) and 5/17 to a bilateral phenotype. A tetrapare sis was present in nine cases, all of which were due to a bilateral cleft. Bilateral forms were significantly associated with tetraparesis, whereas un ilateral forms were associated with hemiparesis. Mental retardation was obs erved in 17 cases (57%), and was observed significantly more often in bilat eral clefts (80%). When both hemispheres are involved, an absence of reorga nization of the brain function between the two hemispheres leads to severe mental deficits, in addition to the cerebral anomaly itself. Eleven patient s had seizures (seven from unilateral and three from bilateral forms). The degree of malformation was not related to the severity of epilepsy. Migrati on disorders, such as dysplasia or heterotopia, were observed in 30% of cas es and are also important etiopathogenetic factors. The septum pellucidum w as absent in 13 cases (43%), with septo-optical dysplasia in two cases. Cor pus callosum dysgenesis was noted in 30% of cases. Four cases of mega ciste rna magna were noted. Although familial cases and environmental factors hav e been previously reported, schizencephaly appears to be, in the majority o f cases, sporadic. (C) 2000 Published by Elsevier Science B.V. All rights r eserved.