Prenatal diagnosis of thrombosed aneurysm of vein of Galen.

Aneurysm of the vein of Galen in the fetus is a rare malformation that has been described in a small number of case reports. Thrombosis of aneurysm of the vein of Galen is a rare occurrence reported in postnatal cases. We report a case of thrombosis of vein of Galen aneurysm occurring in a fetus of 21 weeks' gestation. The fetus showed an echogenic mass posterior and superior to the thalamus. It also showed dilated dural venous sinuses, dilated neck vessels, cardiomegaly and minimal ascites. The pregnancy was terminated and autopsy confirmed the diagnosis. The present case is the first report of the prenatal sonographic features of this condition in the literature.