Hemimegalencephaly misdiagnosed as a congenital brain tumor by fetal cerebral ultrasonography

Abstract

Objective: To describe a case of hemimegalencephaly misdiagnosed prenatally.

Case report: We presented a neonate with hemimegalencephaly, who was thought to have a congenital brain tumor by fetal cerebral ultrasonography. Postnatal MRI findings showed hemimegalencephaly characterized by mild enlargement of the affected hemisphere with a predominantly abnormal signal in the frontal lobe. The appearance of an echogenic round-shaped mass may have resulted from predominant hypermyelination and/or dysplastic neural/glial tissue in the frontal white matter.

Conclusion: In prenatal diagnosis with fetal cerebral ultrasonography, it is difficult to distinguish between congenital brain tumor and hemimegalencephaly in which enlargement of the hemisphere is mild and the affected area of the brain is localized or predominantly in part of a cerebral hemisphere.