Developmental Venous Anomaly: Benign or Not Benign

Abstract

Developmental venous anomalies (DVAs), previously called venous angiomas, are the most frequently encountered cerebral vascular malformations. However, DVA is considered to be rather an extreme developmental anatomical variation of medullary veins than true malformation. DVAs are composed of dilated medullary veins converging centripetally into a large collecting venous system that drains into the superficial or deep venous system. Their etiology and mechanism are generally accepted that DVAs result from the focal arrest of the normal parenchymal vein development or occlusion of the medullary veins as a compensatory venous system. DVAs per se are benign and asymptomatic except for under certain unusual conditions. The pathomechanisms of symptomatic DVAs are divided into mechanical, flow-related causes, and idiopathic. However, in cases of DVAs associated with hemorrhage, cavernous malformations (CMs) are most often the cause rather than DVAs themselves. The coexistence of CM and DVA is common. There are some possibilities that DVA affects the formation and clinical course of CM because CM related to DVA is generally located within the drainage territory of DVA and is more aggressive than isolated CM in the literature. Brain parenchymal abnormalities surrounding DVA and cerebral varix have also been reported. These phenomena are considered to be the result of venous hypertension associated with DVAs. With the advance of diagnostic imagings, perfusion study supports this hypothesis demonstrating that some DVAs have venous congestion pattern. Although DVAs should be considered benign and clinically silent, they can have potential venous hypertension and can be vulnerable to hemodynamic changes.

Fig. 1

A schema showing a developmental venous anomaly (DVA) that is consisted of dilated deep medullary veins in the candelabra zone. Because the caput medusa resembles the deep medullary veins in the candelabra zone, we presume that DVAs may be formed based on the structure of medullary veins that Okudera et al. has described. (1. superior sagittal sinus, 2. developmental venous anomaly, 3. intracortical vein, 4. superficial medullary vein, 5. zone 1 (bamboo–branch union) of deep medullary vein (DM), 6. zone 2 (candelabra zone) of DM, 7. zone 3 (palmate zone) of DM, 8. zone 4 (subependymal zone) of DM, 9. transcerebral vein, 10. longitudinal caudate vein).

Fig. 2

A representative case showing the potential relationship between venous congestion around developmental venous anomaly (DVA) as a trigger of cavernous malformation (CM) formation and bleeding. A 33-year-old man complaining of sudden onset of severe headache presented with a slight left hemiparesis. In this case, CM that was associated with DVA was considered to be the cause of hemorrhage. A perfusion study reveals venous congestion around CM in the territory of DVA. (A) Gadolinium-enhanced gradient-echo T ₁ -weighted MRI showing DVA in the right corona radiata. (B) Susceptibility-weighted imaging showing CM in the right corona radiata, located within the territory of DVA. CT-perfusion image showing an increase of cerebral blood flow (C) and cerebral blood volume (D), and prolongation of mean transit time (E), which is compatible with venous congestion.

Fig. 3

An illustrative case of developmental venous anomaly (DVA) causing symptoms due to decreased outflow. A 55-year-old woman complained of sudden severe headache and vomiting. Angiogram shows the left internal carotid injection (lateral view) in early arterial phase (A) and late arterial phase (B). In the late phase, venous stagnation was observed in the DVA. (C) CT revealing an intracerebral hemorrhage in the left parietal lobe. (D) Gadolinium-enhanced gradient-echo T ₁ -weighted MRI showing DVA in the hemorrhage area. (E) A 3D rotational angiography showing stenosis of a collecting vein at the entrance to SSS. It is considered that the hemorrhage was induced by venous congestion due to DVA with stenosis of the collecting vein ( arrow head ).

Fig. 4

A diagram of symptomatic developmental venous anomalies (DVAs). The pathophysiology of symptomatic DVAs consist of increasing of inflow, decreasing outflow, and mechanical compression. The increase of inflow can result from upstream arteriovenous malformations (AVM), DVA with micro arteriovenous shunt, or DVA with diffuse arteriovenous shunt. The decrease of outflow includes stenosis or thrombosis of outflow vein. The mechanical compression of the outflow vein can result in obstructive hydrocephalus or neurovascular nerve compression syndrome.

Fig. 5

A case of asymptomatic developmental venous anomaly (DVA) with white matter abnormality observed on MRI. A 72-year-old woman underwent brain dock and a DVA was discovered incidentally. (A) Gadolinium-enhanced gradient-echo T ₁ -weighted image showing DVA in the left frontal lobe. (B) T ₂ -weighted image demonstrating high intensity area representing gliosis due to venous congestion within the territory of DVA.

Fig. 6

A case of developmental venous anomaly (DVA) with varix. A 49-year-old woman complaining of intermittent headaches underwent cerebral angiography to evaluate a vascular lesion discovered on MRI (not shown). Angiogram of the left internal carotid injection (lateral view) in the venous phase showing varix formation at the venous outlet of DVA at the vein of Labbé.

Fig. 7

A case of developmental venous anomaly (DVA) with diffuse arteriovenous shunts. A 49-year-old man underwent MR scan for unspecified reason and was suspected of have an arteriovenous malformation. Angiogram was performed to make the final diagnosis. Angiogram of the right internal carotid injection (lateral view) in the arterial phase (A) showing early filling of DVA from the temporo-occipital branch of middle cerebral artery in the late arterial phase (B) with diffuse shunts draining into the vein of Labbé.