P15.10: An anatomic fetal brain structure and a normal variant mimicking anomalies on routine neurosonographic studies. Report of two cases

Abstract

Fetal cranial anatomic structures that were not visualized previously are now perfectly delineated using transvaginal neurosonographic planes. Familiarity with these structures and their normal variants is essential for proper interpretation of prenatal ultrasound studies. Here we present two cases in which a bifidus choroid plexus (a normal variant) and a normal calcar avis (an anatomic fetal structure) mimicked abnormalities on routine ultrasound evaluation of the fetal brain. The first case simulated an intraventricular hemorrhage or a choroid plexus malformation in second-trimester fetal neurosonographic study and the normal variant has been confirmed posteriorly by a neonatal cranial sonography. The second one mimicked an intraventricular clot located within the occipital horn of the lateral ventricle in a third-trimester fetal cerebral study (parasagittal scans). By changing the angulation of the transducer the configuration of the calcar avis could be well recognized. These potential pitfalls have been already reported in the neonates. As far as we know, there are no similar cases described in the fetus.