Prenatal diagnosis of hemimegalencephaly

Abstract

Background: In recent literature, there have been case reports of prenatal diagnosis of hemimegalencephaly, an extremely rare entity characterized by enlargement of all or portions of 1 cerebral hemisphere and intractable seizures. A unique case is presented of hemimegalencephaly of a fetus diagnosed in utero.

Methods: A 27-year-old woman presented at 32 weeks' gestation for fetal magnetic resonance imaging after an abnormal fetal ultrasound. Fetal magnetic resonance imaging showed hemimegalencephaly of the left cerebral hemisphere with abnormal gyration.

Results: The patient was born via cesarean section at 39 weeks' gestation. He had continuous infantile spasms and partial-onset seizures starting on day 1 of life, and electroencephalography showed burst suppression. The patient's seizures were initially managed with antiepileptics, prednisolone, and a ketogenic diet; however, he was hospitalized multiple times because of status epilepticus. At 6 months of age, he underwent a successful anatomic left hemispherectomy.

Conclusions: In utero diagnosis of complex developmental brain anomalies allows a multidisciplinary approach to provide optimal prenatal patient treatment and parental counseling.

Keywords: Cortical dysplasia; Fetal imaging; Hemimegalencephaly; Hemispherectomy; MRI; Neuronal migration.