Hemispherectomy for hemimegalencephaly : A case report of the case complicated by hypomelanosis of Ito and a review of the literature

Abstract

  Hemimegalencephaly is a congenital disorder of brain formation. The most common presentation of hemimegalencephaly is epilepsy, which is often refractory to medical treatment ; consequently, early neurosurgical treatment is recommended. In this report, we discuss a case of hemispherotomy performed on a 3-month-old child with hemimegalencephaly and hypomelanosis of Ito, but the seizures did not improve, and the child subsequently developed hydrocephalus. Reports of patients with hemimegalencephaly who underwent hemispherotomy in early infancy, similar to this case, are limited to case reports. We reviewed the previous reports to examine postoperative complications, seizure prognosis, and developmental outcome. We found that patients who were operated on at ＜5 months of age had more congenital anomalies than those operated on after 5 months of age ; however, they had fewer postoperative complications. There were no significant differences in the prognosis of seizures and development. These results suggest that hemispherotomy for hemimegalencephaly does not increase postoperative complications, even at ＜5 months. In the present case, although it was anticipated that hemispherotomy would relieve clinical seizures originating from the right hemisphere, it did not alleviate the epileptic seizures, which affected both the affected and unaffected sides of the brain. We hypothesized that the accompanying neurocutaneous syndrome, hypomelanosis of Ito, in our patient may have affected the outcomes ; consequently, we investigated postoperative complications, seizure prognosis, and developmental prognosis in reported cases with and without the neurocutaneous complications. In the present study, there was no significant difference in postoperative complications, seizure prognosis, and developmental prognosis among patients with neurocutaneous syndrome compared with those without neurocutaneous syndrome.