Intracranial venous malformations: Incidence and characterization in a large pediatric cohort

Abstract

Background: Significant advances have been reported recently in the genetic and mechanistic characterization of extracranial venous malformations. However, intracranial purely venous malformations (icVM) analogous to those outside the CNS have not been systematically described.

Purpose: We sought to ascertain whether such an entity as icVM could in fact be identified, distinct from previously described CNS venous anomalies and analogous to extracranial venous malformations.

Methods: Our prospectively collected pediatric cerebrovascular database was reviewed to identify patients with icVM; 1458 consecutive angiograms and/or angiographic interventions performed on 706 children at our institution from October, 2006 through May, 2019 were evaluated, in addition to outside imaging studies on 192 additional patients sent to our Vascular Anomalies Center for cerebrovascular review during the same time period. Thus, the cohort consisted of 898 children.

Results: Nineteen of 898 patients (2.1%) were found to harbor icVM, including 9 (47.3%) with sinus pericranii, 15 (78.9%) with associated large, complex extracranial venous malformations, and 3 (15.7%) with neurocognitive delay. There was no intracranial hemorrhage or venous hypertension seen in the cohort. Asymptomatic venous thrombosis in the superior sagittal sinus was seen in three patients.

Conclusion: Venous malformations, both extracranial and icVM, share many characteristics that are distinct from developmental venous anomalies. icVM were not associated with venous hypertension. The underlying genetic mutations involved in the development of icVM, germ-line or somatic, remain to be elucidated, but may very well involve shared mechanisms and pathways with extracranial venous malformations.

Keywords: Brain venous malformation; developmental venous anomaly; extracranial venous malformation; pediatric cerebral vasculature; sinus pericranii.

Figure 1.

Supra-auricular temporalis region extracranial VM. Note the multilobulated, mass-like, non-cylindrical morphology characteristic of VM.

Figure 2.

icVM within the leaflets of the falx (red arrows). The patient additionally has a basal ganglia DVA which empties into the icVM, as well as a glabellar extracranial VM (yellow arrows), which is not in communication with the icVM. Upper panels, left to right: axial T2, T1, and coronal and sagittal post-contrast acquisitions show intense enhancement concordant with venous malformation. Lower panels, left to right: lateral views of arterial, capillary, and venous phases of injection of the left internal carotid artery, and direct injection of the glabellar VM. Note absence of visualization of the icVM on arterial or venous phases, as well as absence of drainage of the icVM out to the glabella and non-drainage of the glabellar VM into the icVM.

Figure 3.

Falcine icVM diagnosed on fetal MRI (upper two panels), along with postnatal MRI follow-up (bottom panels, sagittal T2 and coronal post-contrast T1). Note the posterior drainage of the icVM into the inferior sagittal sinus.

Figure 4.

Several examples of interhemispheric icVM, ranging from far anterior to posterior. Top row: axial post-contrast MR images demonstrating an interhemispheric and left lateral icVM (left panels, red arrows), and lateral views of arterial and venous phases of injection of the left internal carotid artery in the same patient (right panels). Note absence of visualization of the icVM on the arterial phase of the angiogram, with visualization of contiguity with clear venous structures on the venous phase, Bottom row: Examples of interhemispheric icVM in different patients, ranging from far anterior to posterior. Note the characteristic compressible, multilobulated mass-like morphology, with vein-like enhancement and continuity with an adjacent venous structure.

Figure 5.

Basal frontal midline icVM (red arrows) on post-contrast sagittal MR (left panel). Right panels show arterial, capillary, and venous phases of a lateral view of the right internal carotid injection. Note non-visualization of the icVM on arterial and capillary phases and the contiguity of the icVM in this cases with a glabellar VM, with non-contiguity of the icVM with a DVA draining into an enlarged internal cerebral vein.

Figure 6.

Top row: non-midline fusiform icVM, the right-sided example within a schizencephalic cleft. Bottom row: frontal angiographic views of a left internal carotid injection, showing non-visualization of the icVM on arterial and capillary phase images. The venous phase image on the extreme right was acquired several years after the image to its left, demonstrating the dynamic caliber of the icVM over time, neither shrinking nor growing in monotonic fashion; this dynamic appearance over time excludes interpretation of this lesion as being due to venous outlet stenosis with progressive pre-stenotic venous dilatation.

Figure 7.

Globoid icVM morphology appearance on CT, MR, and angiography. Top row images are from one patient and bottom row images from another. Catheter angiography demonstrates the opacification in the venous phase, with delayed emptying.