Purpose: Aneurysms of vein of Galen are rare intracranial malformations of the cerebral arteriovenous
malformations. In the literature the diagnosis of fetal brain AVMs has been limited
to case reports diagnosed usually after 30 weeks of gestation. We present a early
diagnosed case of giant vein of Galen aneurysm in a fetus of a 27 weeks of gestation
with cardiovascular decompensation.
Methods and Materials: Obstetrical sonography was performed to a 23 years old patient at 27 weeks of gestation.
Results: US demonstrated a cystic cranial mass ~3cm in the midline. Color Doppler US showed
the vascular nature of the mass and marked turbulence was demonstrated by the pulsed-wave
Doppler. The dilated serpentine jugular veins were seen in the coronal plane. The
fetus had significant cardiomegaly. There was pleural effusion and ascites suggesting
non-immune hydrops-fetalis with thickening of scalp skin. Due to the giant size of
the lesion and early heart failure, poor outcome has been predicted.
Conclusions: The combination of cardiomegaly with right atrial enlargement and jugular venous
distention in a fetus is highly suggestive of an intracranial arteriovenous malformation.
The main differential diagnosis for the cause of a midline cystic mass is between
a galenic AVM and an arachnoid cyst. Color Doppler US can be used as an important
diagnostic tool for showing the vascular nature of the lession.
