Dysplastic megalencephaly phenotype presenting with prenatal high-output cardiac failure

Dysplastic megalencephaly, also known as bilateral hemimegalencephaly, is a rare cerebral malformation characterized by bilateral cerebral hemisphere overgrowth and extensive malformation of cortical development. Affected patients present clinically with intractable seizures, severe neurological impairment and global developmental delay. There is a small body of literature reporting megalencephaly's association with neonatal high-output cardiac failure and a lack of literature describing prenatal findings. We report a case of dysplastic megalencephaly presenting with progressive high-output cardiac failure during fetal life. Prenatal and postnatal imaging findings as well as neonatal course are described. A companion case with similar imaging findings will help illustrate the prenatal imaging characteristics of this association. Knowledge of this potential complication related to dysplastic megalencephaly may help guide parental counseling and obstetric management.