Prenatal diagnosis of exencephaly

Exencephaly is a rare congenital anomaly, thought to be a precursor of anencephaly, thought to be a precursor of anencephaly. Like anencephaly, this abnormality is characterized by absence of the cranial vault above the orbits. However, unlike anencephaly, discrete, sometimes disorganized, brain tissue can be identified above the cranial defect. In this article, the authors report a case of exencephaly diagnosed prenatally during transvaginal ultrasound examination, with anatomic and pathologic correlation.