Hereditary subependymal heterotopia associated with mega cisterna magna:: antenatal diagnosis with magnetic resonance imaging

Bilateral nodular subependymal heterotopia has recently been identified as a hereditary disease linked to the X-chromosome. The sonographic findings are very subtle and difficult to observe during the second trimester when the germinal matrix is at its largest. Fetal magnetic resonance imaging facilitates visualization of the periventricular area. We report a case of bilateral nodular heterotopia associated with mega cisterna magna diagnosed by ultrasound and magnetic resonance imaging at 2 9 weeks' gestation. Magnetic resonance imaging of the brain of the mother revealed similar findings to those observed in the fetus and neonate. This case confirms the association between mega cisterna magna and bilateral periventricular nodular heterotopia and demonstrates that neuro-imaging studies of the mother can contribute to the fetal diagnosis.