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2.3.1.6 Dural Lesions
Dural lesions can be encountered at any age in children,but represent different disease entities. We will describe them in detail (see Chap. 7, this
volume), since they can represent true malformations in very young children and secondary AV shunts in older patients.The former are encountered in neonates and infants and can be diagnosed in utero (Barbosa
2003) (Fig. 2.8). The latter are usually multifocal and contain large sinuses and high-velocity flow phenomena, but are originally associated with
low pressure in the dural sinuses (Fig. 2.9). They become symptomatic
during childhood and create remote manifestations on the dural sinuses
as well as the cerebral cortex caused by the venous sump effect. Their
treatment is particularly difficult.Different types of dural lesions are encountered with different frequency in various age groups (Scheme 1.3).
2.3.1.7 Telangiectasias
Telangiectasias are usually included in the malformation group and they
are occasionally described in children at autopsy. They are likely to represent improper capillary remodeling (see Sect. 2.7.1). They can be secondary to local ischemia or hemorrhage, but are seldom the cause of it
(Fig. 2.10).
2.3.1.8 The Blue Rubber-Bleb Nevus or Bean Syndrome
The blue rubber-bled nevus or bean syndrome (BRBN) can produce multiple types of central nervous system (CNS) involvement. These features
consist of multiple VMs (venous malformations similar to large telangiectasias), DVAs (developmental venous anomalies) in supratentorial
41The Blue Rubber-Bleb Nevus or Bean Syndrome
Fig. 2.8. In utero MR diagnosis
of dural sinus malformation
(DSM)
Dural AV Shunt in Children
Sinus malformation
High-flow lesions
Multifocal
„Adult“ types
Post-traumatic
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts42
Fig. 2.9A–F. Legend see p. 43.
43The Blue Rubber-Bleb Nevus or Bean Syndrome
▲
Fig. 2.9A–G. A 1-month-old
boy presenting with progressive
macrocrania and referred at the
age of 2 years.A, B Computed
tomography (CT), C magnetic
resonance imaging (MRI), and
D–F angiography demonstrate
a typical multifocal dural arteriovenous lesion with venous
restriction (jugular dysmaturation) at the base and tonsillar
prolapse. G Note the flowrelated aneurysm on the
AICA contribution (subarcuata
artery)
Fig. 2.10A–C. MRI and
angiographic aspect of an
hemorrhagic micro-AVM
or telangiectasia in a child
presenting with a family
history of HHT
brain, cerebellum, and tectum mesencephali (Fig. 2.11). Since its first
description by Bean there have been many cases of BRBN manifesting
with gastrointestinal bleeding with or without associated hemorrhage.
Cases with CNS involvement are rare; many of the reported descriptions
are confusing with various terms used to describe them such as capillary
venous malformation, hemangiomas, and vascular malformations. The
association with DVAs was recognized in some cases but is likely underestimated because of the use of different nomenclature in the published
cases. Although as in Chung’s case (2003) BRBN can be sporadic, its
familial transmission is frequent and the link with HHT1 unlikely despite
the involvement of the same chromosome (chromosome 9p) (Boon et al.
1994; Gallione et al.1995; see Chap. 8,this volume).
2.3.1.9 Venous Malformations (Cavernomas)
Ve n o us malformations are located outside the nervous tissue and therefore do not contain nervous or glial elements.They are referred to as being cavernous and can be isolated or multiple. In the latter case, they are
often familial with autosomal dominant transmission. These lesions are
malformations (Fig. 2.12) and can be found in autopsy series in any location within the intradural space (subarachnoid,subpial).They increase in
size following intralesional hemorrhage. They occasionally have the appearance of a tumor (in particular in children) or a cyst, through confluence of recurrent hematomas.Patients most often present with a hemorrhagic episodes leading to acute symptoms (epilepsy, sudden headache,
deficit, and very occasionally subarachnoid hemorrhage in the case of
subpial location or intraventricular hemorrhage in subependymal le-
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts44
Fig. 2.11A,B. BRBN,blue rubber bled nevus.Association of intracerebral telangiectasia (A, B) and large cerebellar DVA, with capillarectasia (see Chap.8, this volume).
(From Chung 2003)
sions). Different from AVMs in HHT, new cavernomas may become apparent, as the disease is potentially multifocal with other microsatellite
lesions still too small to be detected with imaging.Subsequent growth is
secondary to intralesional hemorrhage, although these episodes may be
subclinical (see Chap. 8,this volume).They can be associated with venous
anomalies or other malformations such as dural sinus AV malformations
(DSMs) (Fig. 2.13) and be induced by radiation therapy.
2.3.1.10 Venous Angiomas or Developmental Venous Anomalies
Ve nous angiomas or developmental venous anomalies (DVAs) are anatomic variations that can involve one or both hemispheres and be located
infratentorially.They do not exist at the spinal cord level or where no secondary germinal matrix migration has occurred. Their symptomatic
character is primarily dependent upon associated malformations (AV or
cavernomatous). The lack of flexibility due to the extreme anatomic disposition of the venous drainage to the brain in the region may also produce ischemic episodes manifesting various levels of clinical severity.The
venous channels are morphologically normal and drain normally functioning brain, although transit time through their venules is sometimes
rapid and almost similar to that in a slow-flow AVM. Careful analysis of
the venous anatomy always provides the necessary information to make
the proper diagnosis. DVAs should therefore never be a target for treatment (see Chap.8, this volume).
45Ve nous Angiomas or Developmental Venous Anomalies
Fig. 2.12A,B. Multiple int radural intraneural and subarachnoid cavernomas in a
young adult (familial case)
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts46
Fig. 2.13. A, B A 6-month-old infant with right frontal cutaneous venous malformation,torcular DSM and posterior fossa DVA. C, D Eight months later,multiple cavernomas with intracerebral hemorrhagic changes are noted. Dramatic enlargement of
the DSM and extension to the right transverse sinus can be seen. (From Mohamed et
al. 2002)
2.3.1.11 Cerebrofacial Venous Metameric Syndrome
(Formerly Sturge-Weber Syndrome)
Cerebrofacial venous metameric syndrome (CVMS, formerly SturgeWe ber Syndrome) consists of cutaneous, facial, port-wine stain (venular malformation), subcutaneous lymphatic malformations (with secondary maxillofacial bone and soft tissue hypertrophy), and cerebral,
cortical vein thrombosis with cortical atrophy, secondary angiogenesis,
and transhemispheric venous drainage, with or without choroid plexus
hypertrophy (Fig. 2.14).The disease is not hereditary.In line with CAMS,
Ramli (2003) suggested the name of cerebrofacial venous metameric syndrome (CVMS; see Chap. 8, this volume). In CVMS, a linkage between
various craniofacial vascular disorders can be identified as related to
the neural crest/mesodermic segmentation. Involvement of the maxillofacial and skull base bone, skin, subcutaneous tissue, and vessels are
in the same metameric distribution. The facial involvement represents
the distal destination of the migrating neural crest cells, contributing
to the vascular network rather than the trigeminal dermatome. The
cerebral abnormalities when present are also in the same metameric distribution.
2.3.1.12 Induced Pial Shunts
Induced pial shunts are unique in juvenile dural arteriovenous lesions
and occur only in children. They develop with the sump effect from the
abnormal dural sinus, retrograde to the cerebral vein, with subsequent
pial AV shunt formation (Figs. 2.9, 2.15). This observation has been confirmed by sequential angiographs and spontaneous post-therapeutic regression of the induced AV shunts (see Chap. 7, this volume).
47Induced Pial Shunts
Fig. 2.14A,B. Cerebrofacial
venous metameric syndrome
CVMS Sturge-Weber
(see Chap. 8,this volume).
A CVMS 1, 2; B CVMS 2,3.
(From Ramli et al.2003)
2.3.1.13 Spinal Cord AVM
Spinal cord AVMs and spinal cord cavernous malformations present the
same characteristics as those mentioned in the brain. Similar to the cranial region, spinal arteriovenous metameric syndromes (SAMS) are recognized, enriching the historical description of Cobb’s syndrome (see
Chap. 15, this volume). Thirty-one segments to the spinal division allow
for single or multimetameric syndromes (Matsumaru et al.1999).
2.3.1.14 General Conclusions on Vascular Lesions
Vascular malformations are multifocal twice as often in children as in
adults.This multifocal character has been underestimated in children due
to poor-quality angiographic studies and lesions not being recognized on
magnetic resonance imaging (MRI). Some can be truly multifocal with interposed normal tissue between two AV shunt niduses (Fig.2.16) and separate or distinct draining veins.Others can be contiguous,simulating compartments within a single lesion. Proof of the presence of these compartments is sometimes hard to establish; however, they may represent
individual therapeutic goals at the time of endovascular treatment. The
most typical is probably CAMS syndrome, which encompasses vascular
malformations in adjacent locations such as the optic nerve, diencephalon,
and occipital cortex. These lesions may reveal sequentially over several
years (as much as 20 years in the cases of Jiarakongmun et al. 2002), illustrating the effect of the surrounding relationships along the migration
pathway on the impaired cells, each region compensating differently (and
revealing differently) for the quiescent defect that originated from the early stages of metameric organization.Some associated lesions cannot be integrated into the CAMS scheme even though obviously linked (Fig. 2.17).
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts48
Fig. 2.15. An 11-year-old girl,
who had presented at the age of
2 with right proptosis related to
an orbital hematoma.Angiography performed at that time failed
to demonstrate any intracranial
anomaly.Over a period of
10 years,she developed progressive right-sided hemiparesis,
dysphasia, and ataxia.Although
angiography had been normal at
the age of 2 at the intracranial
cavity,note the juvenile type of
dural arteriovenous shunt and
the remote cortical and basal pial
arteriovenous communications
(single and double arrows) in-
duced by the lesion.(From
Garcia-Monaco et al.1991c)
Within these multifocal lesions, some may be false AV shunts.Following hemorrhage or ischemia, the true lesion may induce angiogenesis
(neoangiogenesis or capillarectasia) and early venous return. The final
appearance is sometimes difficult to understand unless prior angiography had been performed. Interestingly, the number of thrombosed
lesions also seems to be more frequent on follow-up of CAVMs in children.
2.3.2 Proliferative Lesions
Proliferative vascular lesions in children form a distinct group of disorders; the name „angioma“ is often given indiscriminately to all apparently congenital, nonischemic vascular lesions. The failure to differentiate
between nonproliferative and proliferative lesions has been the source
of misinterpretations and erroneous prediction of the course of the
disease. The name „angioma“ (vascular growth) should be abandoned
or reserved for hemangiomas, which are benign tumors of blood vessel
origin in infants (see Chap. 11, this volume). Some hemangiomas can
be seen intracranially but such localization is rare and usually associated with superficial hemangiomas (see Chap. 12, this volume). Infant
hemangiomas appear to be rare in Asian populations. The older the
child, the more likely the angioarchitecture of these vascular tumors
will be of the cavernous type. Yet some of them keep a capillary angioarchitecture and are called NICH (noninvoluting capillary hemangiomas).
49Proliferative Lesions
Fig. 2.16A,B. A 7-year-old boy presented with generalized seizures in relation to a
brain AVM. Note the multifocality demonstrated at angiography
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts50
Fig. 2.17A–D. A 6-year-old child presented with an external ear capillary lesion on
the left side (A, B),associated with an ipsilateral intracranial cerebellar arteriovenous
malformation (AVM) discovered incidentally (C,D).These findings suggest a CAMS 3
syndrome
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