Developmental venous anomaly
Key concepts
● a vascular malformation that is part of the venous drainage of the involved area with intervening brain present. Therefore direct treatment is rarely indicated
● low-flow, low-pressure
● usually demonstrable on angiography as a starburst pattern
● rarely symptomatic: seizures rare, hemorrhage even more uncommon. Venous infarcts may occur (controversial)
● may have an associated cavernous malformation which is more likely to be symptomatic
Developmental venous anomaly (DVA) AKA venous malformation or (developmental) venous angioma. A tuft of medullary veins that converge into an enlarged central trunk that drains either to the deep or superficial venous system. The veins lack large amounts of smooth muscle and elastic. No abnormal arteries are found. There is neural parenchyma between the vessels. Most common in regions supplied by the MCA or in the region of the vein of Galen. They may be associated with a cavernous malformation.
Non hereditary. These are low-flow and low-pressure.
Most are clinically silent, but rarely seizures and even less frequently hemorrhage may occur. Venous infarcts have been described, but maybe coincidental. If symptoms are present, look for an associated cavernous malformation (GRASS MRI images may reveal some cavernous malformations that might otherwise be occult).
They have mostly supplanted the more pedestrian venous angioma 1).
Congenital malformation of veins which drain normal brain. They were thought to be rare before cross-sectional imaging but are now recognised as being the most common cerebral vascular malformation, accounting for ~55% of all such lesions.
A venous anomaly is characterized by the caput medusae sign of veins draining into a single larger collecting vein, which in turn drains into either a dural sinus or into a deep ependymal vein. The appearance has also been likened to a palm tree.
Pathology
The aetiology of VAs remains uncertain, but may relate to arrested development of venous structures
Histologically they consist of a number of abnormally thickened veins with normal feeding arteries and capillaries
Classification
The most common locations are:
frontoparietal region (36-64%) 1, usually draining towards the frontal horn of the lateral ventricle
cerebellar hemisphere (14-27%) draining towards the fourth ventricle
However, DVAs can be seen anywhere, draining either superficially or deep.
see Spinal cord venous angioma.
Associations
Lesions are usually solitary (75%), except in blue rubber bleb naevus syndrome
~20% (range 8-33%) of cases 2 are associated with cavernous malformations and are referred to as mixed vascular malformations (MVM) there is an association with venous malformations of the head and neck.
Diagnosis
Developmental venous anomaly diagnosis.
Treatment
In general, these should not be treated, as they are the venous drainage of the brain in that vicinity. If surgery is indicated for associated cavernous malformations, the angioma should be left alone. Surgery for the angioma itself is reserved only for documented bleeding or for intractable seizures that can be definitely attributed to the lesion.
Case series
Fifty-two children (20 boys and 32 girls [median age: 6 years] were identified with DVAs. Their age distribution was as follows: 1.9% neonates (< 1 month), 11.5% infants (1 month to 1 year), 30.8% 1-5 years, 30.8% 5-12 years and 25% 12-16 years. The majority (92.3%) presented with asymptomatic DVAs identified incidentally. Overall, anatomical distribution revealed predilection for frontal region (42.3%) with other common sites being posterior fossa (17.3%) and basal ganglia (13.5%). Temporal (11.5%), parietal (9.6%) and occipital (5.8%) were the remainder. Associated cavernous malformations (CMs) were present in 3/52 (5.8%), and no DVAs were associated with aneurysms or arteriovenous malformations (AVMs). Three patients had more than one DVA. There were three deaths unrelated to DVAs over median follow-up of 3.8 years. Four patients (7.7%) suffered DVA-related intracranial haemorrhage presenting with neurological deficits. The ages of the children with DVA-related haemorrhages were 21 days, 2 years and 6 months, 7 years and 1 month and 11 years and 7 months. Left-sided DVA haemorrhages predominated (3/4, 75%). The relative risk of a cerebellar DVA haemorrhage compared to its supratentorial counterpart was 5.35 (OR 6.8, 95% CI 0.8-58).
DVA-related haemorrhage is sevenfold greater in the paediatric cohort compared to adults and is significantly associated with a cerebellar location and cavernous malformations. There were no haemorrhages over a median period of 3.8 years of prospective follow-up 2).
Case reports
A 27-year-old woman who presented with a sensorineural hearing loss followed by facial paresis. Magnetic resonance imaging (MRI) and computed tomography (CT) angiography revealed hematoma with adjacent converging veins showing a typical “caput medusa” sign in the left middle cerebellar peduncle, in favor of DVA. Due to the compression effect of hematoma, she underwent surgery. Hearing loss and facial paresis improved significantly during the postoperative follow-up.
Although DVA is mostly benign and asymptomatic, complications such as hemorrhage rarely occur. Hearing loss is an extremely rare presentation that can be attributable to the compression effect on the cranial nerve VII to VIII complex. In the case of compression effect or progression of symptoms, surgical intervention is necessary. A good clinical outcome could be expected postoperatively 3).
Although the association of developmental venous anomalies (DVAs) with cavernous malformations is well documented, the association with arteriovenous malformations (AVM) is unusual. The aim is to report an additional case and to review the concepts associated with these mixed malformations in order to guide patient management.
A case of AVM associated with a DVA was identified and a literature review was performed according to PRISMA guidelines.
Case report: In an 18-year-old man presented with sub-acute headache but with a normal neurological examination, the MRI-scan showed a right occipital DVA associated with hemosiderin spots evocative of earlier asymptomatic bleedings. The Digital Subtraction Angiography revealed a right parieto-occipital Spetzler-Martin Grade III AVM, fed by branches from the right middle and posterior cerebral arteries, with a superficial drainage flowing into a DVA that then joined the superior sagittal sinus. Multistep embolization was performed, leading to a partial reduction of the nidus, but preserving the DVA permeability. After a six-year follow-up. bleeding did not recur and the MRI aspect of the malformation was perfectly stable.
The co-occurrence of a DVA and an AVM is rare but has a higher bleeding risk than AVM alone (69% vs 38%) and must consequently be suspected when a DVA is revealed by a hemorrhage, in the absence of associated cavernoma. These mixed malformations represent a therapeutic challenge that has to be tailored to the venous anatomy and to the malformation Spetzler-Martin grade. DVA permeability should be preserved to avoid deleterious venous infarction 4)