Hydrocephalus due to Galen vein aneurysm associated with arteriovenous malformation in an adult patient

Great Galen vein aneurysms are rare intracranial vascular malformations which are especially seen in the neonatal period. They comprise a diverse group of vascular anomalies, and different classifications are described in the literature [1]. Hemodynamically, Galen vein aneurysms are classified into two types. One type comprises the true vein of Galen malformations (VOGMs), which constitute 1% of all intracranial vascular malformations and most commonly affect the neonatal population, in whom congestive heart failure is the primary presentation. These lesions are characterized by the presence of an aneurysmally dilated deep venous structure, fed by abnormal arteriovenous communications. The second classification is Galen vein aneurysmatic dilatation due to high flow parenchymal arteriovenous malformation (AVM), which produces engorgement and dilatation of the Galen vein. We report a rare case of Galen vein aneurysm caused by AVM leading to obstruction at the cerebral aqueduct.
A 57-year-old man with metastatic lung cancer presented to the neurology department with complaints of fatigue and insomnia. The physical examination revealed mild motor weakness at the left arm. The other neurological tests were normal. The blood test results showed mild anemia due to chronic disease, increased low-density lipoproteins (LDH) and decreased levels of 25-hydroxy vitamin D. Brain magnetic resonance imaging (MRI) was performed (1.5 Tesla, Siemens, Avanto, Erlangen, Germany) and revealed multiple metastatic lesions in cerebral and cerebellar hemispheres with heterogeneous contrast enhancement and diffuse vasogenic edema around the lesions on T2 weighted images (Figure 1 A). The arteriovenous malformation was visualized at the deep medial part of the left temporo-occipital lobe. The nidus was seen at the central part of the AVM after contrast administration (Figure 1 B). The arterial feeder was the posterior cerebellar artery, and the venous drainage was supplied by the internal cerebral vein, which drains into the Galen vein. The Galen vein was observed to be aneurysmatic due to increased blood flow and probably due to obstruction. The aneurysmatic Galen vein caused obstruction at the level of the cerebral aqueduct, leading to noncommunicating hydrocephalus (Figures 2 A, B).
The vein of Galen, also named the great cerebral vein, is a venous structure formed by the two internal cerebral veins and the basal veins of Rosenthal and lies at the quadrigeminal...


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