Thrombosed Aneurysm of the Vein of Galen

Abstract

Computed tomography in a 3 1/2-year-old boy with ataxia, lethargy, fever, vomiting, and increasing irritability revealed moderate hydrocephalus and a blood density mass lesion lying superior and posterior to the 3rd ventricle. On several of the sections, the blood density was greater in the dependent than in the superior portion of the mass. The average attenuation number within the mass was 40 EMI units. The infusion of contrast agent demonstrated capsular enhancement (a target sign), which was also demonstrated by angiography. The diagnosis, which was confirmed at operation, was thrombosis of an aneurysm of the vein of Galen. The massive thrombus was resected, but the aneurysm was not excised. The patient's recovery was uneventful.

Conservative Management of Thrombosed Vein of Galen Malformations

“…In patients with a solid mass in the area of the pineal gland, the diagnosis of thrombosed vein of Galen malforma tion may be safely made only after careful and thorough radiographic evaluation of the lesion. The presence of a 'target sign' on CT studies is supportive of the diagnosis [12], MRI as a diagnostic modality may have tremen dous value in the diagnosis of these lesions. At present, the experience is limited to our 2 cases.…”

Intracranial Arteriovenous Anomalies of Infancy: Modern Concepts

“…Other cases of venous compres sion of CSF pathways have also been reported [30]. Hydrocephalus is frequently present when the VGA is thrombosed but the exact cause of the hydrocephalus in these cases is unclear [17,32], Measurement of sagittal sinsus pressure, before and after occlusion of the AVF, has shown high pressures that become normal after oc clusion [23]. This elevated sinus pressure may impede CSF absorption leading to ventricular enlargement.…”

“…The procedure is simplified by leav ing the sac in place and avoids the risk of causing im pairment in venous drainage. In instances where the varix is clotted, removal of the thrombus from the venous sac may be appropriate, but again the vein itself need not be removed [32].…”

Spontaneous Thrombosis of Vein of Galen Aneurysmal Malformation

“…A crescentic rim of calcification of AVG was reported as early as 1945 [26]. Skull films reveal rim calcifications in about half of the reported cases of thrombosed AVG [27]as compared to 14% of patients without thrombosis [12]. Even though it is noted that a high percentage of thrombosed aneurysms are calcified, calcification of an AVG does not predict a tendency for that structure to subsequently thrombose.…”

“…Heinz et al [5]originally suggested that aneurysms thrombose prenatally or during the birth process; Lazar [40]and Six et al [27]refuted this hypothesis because of the presence of organized thrombi and fresher clots in their patients at the time of surgery.…”