279 / 280
and often times seen in the setting of syndromes such as KT.
Even in those patients with KT, LM and VM are seen sepa-
rately (
Figs 1
and
10
). Mixed LVMs are generally found as
super
fi
cial lesions in
fi
ltrating the skin or tongue (
Fig 11
).
Cavernous malformation-arteriovenous malformation
CM-AVM is an autosomal dominant condition that con-
sists of cutaneous CMs and high-
fl
ow arteriovascular mal-
formations. These lesions are also formed due to a RASA1
mutation. On physical examination, the CMs, previously
described as port-wine stain, are
fl
at reddish lesions.
42
In
contrast to typical CMs, those associated with CM-AVM are
usually smaller, multiple, and associated with an encircling
pale halo.
43
Treatment usually involves embolization of the
underlying AVM.
Syndromes associated with vascular malformations
VaMs can also be associated with syndromes (
Table 4
). In
contrast to isolated VaM, limb overgrowth is more common
in the syndromal VaM. KT, blue rubber bleb nevus syndrome
(BRBNS), unilateral limb VM, mucocutaneous VMs, Stur-
ge
e
Weber, Proteus, Congenital Lipomatous Overgrowth,
Vascular Malformations, and Epidermal Nevi (CLOVE) syn-
drome, Maffucci, and Gorham
e
Stout syndromes are
all associated with low
fl
ow-VaM. Parkes
e
Weber,
Rendu
e
Osler
e
Weber, Cobb and Wyburn
e
Mason syn-
dromes are associated with high-
fl
ow VaM. PTENmutations
in syndromes such as Bannayan
e
Riley
e
Ruvalcaba and
Cowden syndromes also result in high-
fl
ow VaM.
44,45
We
will discuss some of the more commonly encountered syn-
dromes associated with VaM.
Syndromes associated with venous malformations
Klippel
–
Trenaunay syndrome
KT is characterized by hypertrophy of the affected limb
with slow-
fl
ow VaMs, including CMs of the skin with un-
derlying extensive VMs and/or LMs (
Figs 1
and
11
).
Dysplastic/anomalous veins or persistent embryonic veins
can be observed. The deep venous system may be atretic,
hypoplastic, or abnormal in approximately 50% of patients
with KT and must be con
fi
rmed patent prior to ablation of
the super
fi
cial abnormal veins. These patients can vary from
a mild form, to a more severe form with extensive
involvement of the pelvis and viscera as well as the legs.
Some may have more LMs, others may have more VMs, and
some may have enlarged ectatic pelvic and leg veins. KT
patients may also be at higher risk for pulmonary embolus
and need to be evaluated for potential long-term
anticoagulation.
46
Blue rubber bleb nevous syndrome
BRBNS is characterized by multiple cutaneous VMs as
well as internal VMs, typically involving subcutaneous tis-
sues and muscles in numerous locations (
Figs 1
and
12
).
Cutaneous lesions are often present shortly after birth and
increase in size and number with growth of the child.
Physical examination
fi
ndings demonstrate small, bluish
raised lesions, which can often be painful. These patients
must be followed due to multiple small bowel lesions that
frequently bleed, presenting in early adulthood as slow,
chronic gastrointestinal bleeding and chronic iron-
de
fi
ciency anaemia.
47,48
Unilateral limb venous malformation
Some patients with diffuse VMs in an extremity do not
have KT (no hypertrophy, no LM, no port-wine stain) and
are classi
fi
ed as having unilateral limb VM
49
(
Figs 1
and
13
).
The skin may appear bluish due to the VM in the subcu-
taneous region. They typically have numerous deeper VMs
within muscles from the pelvis to the feet.
Mucocutaneous venous malformation
This is an autosomal dominant inherited VM with mul-
tiple bluish spots that are usually small and punctuate and
painful to touch, but may be larger in size.
32
Glomuvenous malformation
This is also an autosomal dominant inherited VM in
which there are multiple small bluish to purple skin le-
sions
32
(
Figs 1
and
14
).
Syndromes associated with arteriovenous malformations
Parkes
e
Weber syndrome
Parkes
e
Weber syndrome (previously called Klip-
pel
e
Trenaunay
e
Weber syndrome) is not a VM syndrome,
but is characterized by hemihypertrophy of usually the
lower limb, CM, and diffuse multiple tiny super
fi
cial arte-
riovenous shunts
50
(
Figs 1
and
15
). Unlike KT, Par-
kes
e
Weber is a fast-
fl
ow malformation due to the presence
of arteriovenous
fi
stulas. Pathogenesis is due to a RASA1
gene mutation on chromosome 5q13.1. RASA1 gene encodes
for p120-RasGAP protein that promotes signalling of several
growth factor receptors involved in proliferation, migration,
and survival of vascular endothelial cells. On physical ex-
amination, the lesion is usually pinkish to red with diffuse
areas of involvement.
51
MRI is helpful in classifying the
malformation as a fast
fl
ow arterial or AVM, which helps
differentiate from KT. Treatment usually involves multi-
staged embolizations to improve high-output cardiac fail-
ure and help save the limb.
Conclusion
ISSVA classi
fi
cation not only provides accurate diagnosis,
but also provides a common language for clinicians
involved the care of the vascular anomalies. SEMVAFC in-
corporates the ISSVA classi
fi
cation to provide a clear visual
pathway and a practical multidisciplinary approach to ac-
curate classi
fi
cation of highly complex VA.
References
1.
Hassanein AH, Mulliken JB, Fishman SJ, et al. Evaluation of terminology for vascular anomalies in current literature. Plast Reconstr Surg 2011; 127 :347 e 51 .A. Tekes et al. / Clinical Radiology 69 (2014) 443
e
457
257