Case report

This is a 28 years-old patient, at 13th week with a previous child affected by holoprosencephaly (type unspecified). Scanning revealed normal findings. The patient was advised to have the next scan before 20th week of gestation, because of an increased risk of midline brain defects. The next ultrasound examination about 20 weeks at a different institution failed to reveal any abnormalities. The brain anomaly was only seen at about 28 weeks. The patient came again to my office for scanning and the semilobar type of holoprosencephaly was suspected.

This case emphasizes importance of a 20 weeks scan, as the semilobar and lobar types of holoprosencephaly can be difficult or impossible to diagnose in the first trimester.

Discussion

This case raised an interesting discussion started by Moshe Bronshtein, MD (Haifa, Israel). In his opinion in this case does not represent holoprosencephaly, but hydrocephalus that caused the destruction of the midline, because the earlier presence of the falx cerebri and its remnant later in pregnancy is criterion favoring the diagnosis of hydrocephalus.

We have asked other authors for their opinion and here are their remarks:

Ritsuko Pooh, MD (Japan)

I agree with Dr. Bronstein. Progressive hydrocephalus often destructs the falx and midline. Holoprosencephaly occurs as an early event. It is difficult to differentiate clearly holoprosencephaly from progressive hydrocephalus at late pregnancy, but I think remnant falx and remnant anterior horn of ventricles are evidences of progressive hydrocephalus.
Because holoprosencephaly semilobar type and progressive hydrocephalus have quite different prognoses, we have to diagnose them prudently.

Ilan Timor Tritch, MD (USA)

I agree with Dr. Moshe Bronstein.

Gianluigy Pilu, MD (Italy)

Does it matter :-) ?

Images 1, 2: 13th week of pregnancy; 2D ultrasonography. Transverse planes through fetal head showing unremarkable intracranial anatomy.

Images 3, 4: 13th week of pregnancy; Normal ductus venosus waveform pattern (left); and sagittal plane showing normal nuchal translucency and presence of nasal bone.

Images 5, 6: 28th week of pregnancy; 2D ultrasonography. Coronal planes through fetal skull - remnant of the falx cerebri is visible on the image 5.

Videos 1, 2: 28th week of pregnancy; 2D sonography. Video 1 shows normal appearance of fetal face. Video 2 represents transverse plane through fetal head.

Videos 3, 4: 2D sonography. Comparison between unremarkable 13th week intracranial anatomy (left) and 28th week scan showing severe hydrocephalus (right).