Vein of Galen Malformation

Updated: Nov 18, 2015
  • Author: Raj D Sheth, MD; Chief Editor: Amy Kao, MD  more...
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Overview

Background

The vein of Galen is located under the cerebral hemispheres and drains the anterior and central regions of the brain into the sinuses of the posterior cerebral fossa. The vein of Galen aneurysmal malformation is a choroidal type of arteriovenous malformation involving the vein of Galen forerunner and is distinct from an arteriovenous malformation with venous drainage into a dilated, but already formed, vein of Galen.

Aneurysmal malformations of the vein of Galen (VGAM) typically result in high-output congestive heart failure or may present with developmental delay, hydrocephalus, and seizures. [1]

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Pathophysiology

Vein of Galen malformation (VGAM) results from an aneurysmal malformation with an arteriovenous shunting of blood. The congenital malformation develops during weeks 6-11 of fetal development as a persistent embryonic prosencephalic vein of Markowski; thus, VGAM is actually a misnomer. The vein of Markowski actually drains into the vein of Galen.

VGAM usually causes high-output heart failure in the newborn resulting from the decreased resistance and high blood flow in the lesion. Associated findings include cerebral ischemic changes such as strokes or steal phenomena that result in progressive hemiparesis. Hemorrhage from the malformation can occur, although this is not a common finding. Finally, the malformation may result in mass effects, causing progressive neurological impairment. Alternatively, the malformation may cause obstruction of the cerebrospinal fluid (CSF) outflow and result in hydrocephalus. [2]

Vein of Galen malformation has been associated with capillary malformation-arteriovenous malformation (CM-AVM), which is a newly recognized autosomal dominant disorder, caused by mutations in the RASA1 gene in 6 families. The authors report severe intracranial AVMs, including vein of Galen aneurysmal malformation, which was symptomatic at birth or during infancy, extracranial AVM of the face and extremities, and Parkes Weber syndrome, previously considered sporadic and nongenetic. [3]

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Epidemiology

Frequency

The incidence of the vein of Galen malformation is unknown.

Mortality/Morbidity

Infants often die if the high-output congestive heart failure is the presenting feature.

Macrocephaly usually improves following shunting for hydrocephalus.

Demographics

VGAM is a congenital malformation; therefore, it may present at birth or in early childhood. It occurs in all races, and boys and girls are affected equally.

 

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Prognosis

Fetuses with prenatally diagnosed VGAM have unexpectedly poor outcomes in the presence of cardiac or cerebral anomalies, while those with strictly isolated VGAM tend to have more favorable outcomes. Of 21 cases of prenatally diagnosed VGAM, 4 (19.0%) cases were isolated and 17 (81.0%) were associated with other anomalies. There were nine terminations (42.9%) and six neonatal deaths (28.6%). [4]

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