This group of conditions, which can affect infants, children, and adults,
continues to be a source of concern and confusion for patients and their
families, despite having been described for hundreds of years. One of
the principal problems is in making the proper diagnosis, which then
dictates which tests and procedures should be done. Most medical practitioners
see these problems so infrequently that they are unsure as to the best
course of action. In many cases, once the proper diagnosis is made,
nothing more need be done beyond assuring the patient and family that
the condition will follow a benign course.
A look through the medical literature (and now the internet) will reveal
a wide range of terminology, including hemangioma, vascular birthmark,
port wine stain, vascular malformation, arteriovenous malformation,
venous malformation, cavernous venous malformation, Klippel Trenaunay
Syndrome, Parkes Weber Syndrome, hemangioendothelioma, and lymphatic
malformation, among many others. Many of these terms are equivalent
or are no longer considered accurate. After 25 years of dealing with
these problems, I find that it is helpful to simplify things by dividing
these conditions into only five groups: Hemangioma, Arteriovenous Malformation,
Arteriovenous Fistula, Venous Malformation, and Lymphatic Malformation.
Each of these conditions is distinct in terms of diagnosis, prognosis,
and treatment. Let’s consider each of these individually.
This term is commonly (and mistakenly) applied to all vascular lesions,
but it actually describes a very distinct condition which is confined
to infants and children. This is the lesion commonly seen in infants
and referred to as a “strawberry birthmark”. It is quite
common in the general population, occurring in up to 12% of infants.
It is significantly more common in premature infants, females and in
the Caucasian population, and may be present at birth or appear shortly
thereafter. It is a single lesion in most infants, but can be multiple
on occasion. This is not a malformation or “birthmark” per
se, but a benign tumor of endothelial cells (the cells which normally
form the walls of blood vessels). What makes these conditions unique
is their characteristic of going through three distinct stages: appearance
(at birth or shortly thereafter), the proliferative stage (weeks to
months) and the involution stage (the lesion spontaneously resolves
by itself, usually by the age 7 or 8 years). This course of events is
quite unique biologically, making hemangiomas a subject of intense interest
to researchers in conditions where blood vessel development plays a
major role, ranging from atherosclerosis to cancer.
Diagnostically, most hemangiomas have such a typical appearance and
follow such a predictable chronological course that the diagnosis is
easily made clinically and no further diagnostic testing is required.
On occasion, a lesion located more deeply and appearing as just a soft
tissue mass may require imaging studies (CT, MRI) or rarely a biopsy
to confirm the diagnosis. While CT and MRI scans are “non-invasive”
tests, they will generally require sedation or anesthesia in infants
and children, so that their use is reserved for lesions which are of
indeterminate nature clinically or when treatment is required. When
would treatment be required in this condition? This is a controversial
area, but most experts would agree that those hemangiomas which interfere
with breathing, feeding, or visual development should undergo treatment.
There are also hemangiomas which grow so rapidly during the proliferative
stage that they can present with painful ulceration and bleeding requiring
intervention. On occasion, hemangiomas can occur in the liver, where
they can be so large and have such high flow that they put a strain
on the heart; these lesions will also require more aggressive treatment.
Finally, there is a rare variant called Kaposiform Hemangioendothelioma,
which tends to occur over the trunk, thigh, or shoulder, and has an
unusual diffuse reddish or purple color with thickening of the skin
which resembles inflammation. This specific type of hemangioma has a
tendency to consume platelets from the blood (the cells which are part
of the normal clotting mechanism), which can in turn lead to bleeding
complications (referred to as Kasabach-Merritt Syndrome).
If treatment is required for hemangiomas, it usually consists of a
combination of local care (topical treatment) combined with systemic
therapy, generally oral steroids. Steroids have been used for decades
in treating hemangiomas and are still considered the mainstay of therapy
when it is required. Steroids should be administered by pediatricians
with specific expertise in treating hemangiomas, as dosage, timing,
and duration of therapy must be judged and monitored closely, due to
potential side effects, including suppression of the immune system.
Other drugs, including interferon and cytotoxic drugs, are used less
frequently now due to their much greater potential toxicity. Radiation
treatment was used in the past but has no current role in the management
of hemangiomas due to the risks of local tissue damage as well as the
potential for long term carcinogenesis (tumor formation).
Until very recently, surgery was felt to play little role in the treatment
of hemangiomas, due to their tendency to resolve spontaneously over
time. Aside from the unusual situation where surgery is required for
hemangiomas involving respiratory, digestive, or visual structures,
there has been a resurgence of interest in lesions causing cosmetic
deformity, particularly on the face. While it is true that small lesions
will disappear over time leaving almost no trace, extensive lesions
may leave behind pale, atrophic skin after involution, in some cases
requiring plastic surgery to achieve an acceptable cosmetic appearance.
Some plastic and head and neck surgeons feel that earlier surgical removal
in these cases may be preferable, not only achieving an immediate improvement
appearance but also avoiding the psychosocial difficulties which may
be encountered by patients (especially children) with a cosmetically
In summary, hemangiomas are benign blood vessel tumors which occur
in infants and children. They typically progress through a proliferative
stage where they may show rapid growth, and then tend to involute (or
resolve) spontaneously in early childhood without treatment. Due to
this typical benign, self-limited history, management is conservative
in most patients. When treatment is required, it should be under the
care of physicians with specific expertise in this area.
Arteriovenous malformations, also referred to as vascular malformations
or AVMs, are congenital abnormalities in the local development of the
blood vessels, usually confined to a single anatomic area. In the normal
development of the circulatory system, there is initially a primitive
system with poorly defined vascular “lakes”. As the embryo
and fetus develop, there is a progressive complex process of refinement
(still not completely understood) where these primitive structures develop
an organization into arteries (carrying oxygenated blood away from the
heart), capillaries (tiny networks where the oxygen is actually delivered
to the tissues), and veins (which carry the deoxygenated blood back
to the heart). A vascular malformation represents the localized failure
of this process, resulting in a disorganized structure where arteries
and veins connect without the normal tapering of vessels into a capillary
bed. The size of the abnormal direct connection between arteries and
veins will determine the amount of flow “short-circuited”
through the malformation. If the malformation is small or deeply located,
it may be of little or no clinical significance. If the malformation
is larger or in a more critical location, it can have significant effects
locally or even on the entire body.
Since these are not tumors but just abnormal areas of tissue development,
they tend to grow along with the individual. Unlike hemangiomas, they
do not resolve spontaneously; this is why it is critically important
to make the specific diagnosis and not lump all vascular lesions under
the term “hemangioma”.
Depending on where they are located and the amount of abnormal flow
through them, they may show up at any time in life from infancy to adulthood.
One common but poorly understood aspect of vascular malformations in
female patients is their apparent increase in size and symptoms at times
of increased hormonal activity, specifically puberty and during pregnancy.
We commonly see the first complaints related to the malformation when
a young girl reaches puberty or is in her early teens; these patients
may also note that symptoms are worse at certain points in the menstrual
Arteriovenous malformations can occur anywhere in the body and are
usually isolated abnormalities in otherwise normal, healthy individuals.
They are congenital but not genetic (with rare exceptions), meaning
that there is little likelihood of passing them on to one’s children,
little likelihood of siblings having the same problem, and rarely any
family history of vascular malformation. There are rare genetically
transmitted familial syndromes (such as Rendu Osler Weber Syndrome)
where multiple family members will have multiple AVMs, but most affected
families will already be aware of this condition. Unlike hemangiomas,
there is no tendency for them to occur in females and they seem to occur
with equal frequency in all races and ethnic groups.
Depending on where in the body they are located, their size, and the
amount of abnormal flow through them, AVMs can range from being asymptomatic
lesions requiring no treatment to life-threatening problems in rare
cases. If they are near a skin surface they may present as a soft tissue
mass with or without changes in the overlying skin. If the flow is rapid
enough, a pulsation may be felt over the area, and the blood vessels
leading to and way from the malformation may be enlarged and pulsatile.
They usually cause no pain and are not tender to the touch. If the flow
is very rapid, it may cause blood to flow through the short-circuit,
where the pressure is lower, rather than to the normal tissues in the
area. This can lead to the seemingly paradoxical situation of having
excessive blood flow to the general region but signs and symptoms related
to the lack of flow to the normal structures beyond the malformation
(localized ischemia). When the malformation is located in an extremity,
this may be manifest by pain on exercise, atrophy of tissues in the
hand or foot, or even breakdown of the skin integrity (ischemic ulceration).
In some patients, their major presenting problem is this distal ischemia,
rather than at the site of the malformation itself. The veins draining
the malformation are also subjected to flow and pressure they were not
designed to handle, resulting in dilation and thickening of the veins,
eventually leading to secondary changes of “venous hypertension”.
The veins under pressure can cause localized thickening and eventual
deterioration of the overlying skin similar to that seen in patients
with severe varicose veins, sometimes resulting in ulceration. Treating
the underlying vascular malformation will usually reverse these changes
to a great extent.
If the abnormal flow through an arteriovenous malformation is extremely
high, there can be generalized effects on the entire cardiovascular
system. These effects can include increased blood volume, elevated heart
rate, and in rare cases, heart failure. These changes, while mentioned
in every text book and often mentioned by pediatricians and internists
as a concern, are actually quite rare in practice. Out of over a thousand
patients treated with vascular malformations in 25 years, I have seen
only a handful of patients with this problem. It is generally seen in
the setting of a small child with a very large shunt (short circuit)
or in the rare adult with an extremely high flow AVM. In these cases,
treatment of the malformation can be life-saving.
Another concern is that of bleeding or hemorrhage related to the malformation.
Major bleeding is exceedingly rare, and is usually associated with ulceration
of the skin or internal involvement of the gastrointestinal or urinary
tracts. The risk in other patients is so low that I never limit a patient’s
activities, whether child or adult, with the possible exception of such
activities as swordfighting.
When vascular malformations are located in certain parts of the body,
specific issues and concerns arise. Vascular malformations in the pelvis
can involve the bladder, colon, or uterus, potentially causing bleeding
from any of these organs. I have treated many women with pelvic AVMs,
and the question of fertility and risk of pregnancy is always raised.
The normal changes which occur during pregnancy cause enlargement of
the AVM and an increase in flow through it, sometimes increasing symptoms.
Unless the AVM involves the uterus itself, fertility is generally not
adversely affected and a normal delivery is possible in most patients,
although involvement of a specialist in high-risk pregnancy is advised.
Two other anatomic locations which pose unique problems are pulmonary
AVMs and those involving the central nervous system (brain and spinal
cord). Pulmonary AVMs are unusual in that they represent a short circuit
in the lung blood vessels where blood from the veins is directly shunted
into the arterial circulation. This has two potential effects –
the oxygen level in the blood may be reduced, causing shortness of breath
and decreased exercise tolerance, and the filtering function of the
lung is partly lost, allowing blood clots from the venous system to
reach the arterial circulation. This can result in a condition called
paradoxical embolism, with the possibility of stroke. Vascular malformations
involving the brain or spinal cord are complex management problems;
they may be asymptomatic but can cause bleeding or a mass effect (like
a tumor) in the closed space of the skull. Vascular malformations involving
the nervous system should be managed by physicians with highly specialized
expertise in this area (certain neurosurgeons and interventional neuroradiologists).
The treatment of arteriovenous malformations depends on the size, location,
and clinical problem resulting from the lesion. Small, asymptomatic
lesions which are discovered incidentally do not require specific treatment
once the diagnosis has been confirmed by imaging studies or angiography.
In the majority of patients, the diagnosis can be confirmed on non-invasive
imaging studies – ultrasound, CT, or MRI scans – and angiography
is only performed if the diagnosis is in doubt or if endovascular (embolization)
treatment is planned (see below).
When treating vascular malformations, two things must be kept in mind
– first, they are generally benign conditions which show little
or no progression once growth stops, and two, it is difficult or impossible
to “cure” or eradicate them completely, as they have a strong
tendency to recur regardless of the type of treatment performed. Therefore
treatment should be directed at eliminating symptoms with a minimal
degree of risk and
invasiveness. Surgical removal is generally not possible except in very
localized malformations; since these are benign lesions, heroic “cancer
type” surgery is inadvisable, as it is not necessary and may replace
a relatively minor problem with significant scarring or disability.
Embolization treatment has assumed a major role in treating vascular
malformations, as it combines minimal invasiveness with a significant
reduction in symptoms. The principle involves passing a small catheter
through the arterial system into the specific arterial branch supplying
the malformation; an embolic agent is then injected through the catheter
under fluoroscopic (x-ray) guidance into the center of the malformation
(the nidus). A range of materials has been specifically developed for
this purpose, including certain polymers, acrylic adhesives, microspheres,
ethanol, and platinum coils. Each embolic agent has advantages and disadvantages,
the choice being made on the basis of the type of malformation and the
experience and preference of the physician performing the procedure.
The procedure is performed under IV sedation or general anesthesia;
there is no incision – the only entry point is a needle puncture
in the femoral artery at the top of the leg. The patient is generally
observed overnight and goes home the following morning. Depending on
the size and location of the malformation, one or a series of treatments
may be required.
In terms of treatment results, approximately 80% of patients can expect
marked improvement or elimination of symptoms following treatment; 15%
of patients can be “cured” completely, meaning there is
no evidence either clinically or radiologically that there is any residual
malformation. Again, as these are benign conditions, resolution of symptoms
rather than complete eradication should be the goal. Potential complications
of embolization treatment are of two types – those occurring at
the arterial entry site (bleeding, hematoma or bruise, damage to the
artery), and those related to the actual embolization, where too much
blood flow is stopped, the wrong artery is blocked, or the embolic agent
passes through the malformation completely and reaches the vein or pulmonary
circulation. In experienced hands, the significant complication rate
should be less than 1%.
An arteriovenous fistula is a direct abnormal connection between an
artery and a vein, allowing blood to shunt directly from the high pressure
artery to the low pressure vein. This problem is usually related to
a penetrating injury, which can be traumatic or iatrogenic (the result
of a medical procedure). A small fistula may close by itself without
treatment, but larger ones will enlarge over time, eventually resulting
in the same kinds of problems seen with congenital vascular malformations
(increased flow, enlarged vessels in the area, stealing of flow away
from normal tissues, and increased cardiac work).
Fistulas have been described since antiquity, usually related to war-related
injuries. If treated early, before the surrounding blood vessels become
abnormally enlarged, arteriovenous fistulas can usually be completely
cured by either surgery or embolization. It is essential that the actual
point of connection between the artery and vein be closed, or other
blood vessels in the region (collaterals) will be drawn into the process,
making subsequent treatment more difficult. Since the anatomy of a fistula
is much simpler than a congenital malformation (single hole versus tangle
of abnormal connections), the likelihood of complete cure is much greater.
Congenital fistulas (present at birth) are rare but do occur, both
in the brain and elsewhere in the body, such as the lung and kidney.
Due to the very high flow through these vessels, treatment can be technically
difficult but a complete cure is possible in most cases.
Venous malformations are the commonest type of malformation occurring
in the general population, probably five times more common than arteriovenous
malformations. Other terms applied to this condition are cavernous venous
malformation and cavernous hemangioma (the latter a misnomer, as hemangioma
should refer only to the benign vascular tumor of infancy). These malformations
can range from a superficial skin lesion, sometimes referred to as a
“port wine stain”, to abnormal development of the entire
deep venous system of an extremity. Like congenital arteriovenous malformations,
these are problems of vascular development present from birth, congenital
but not genetically transmitted. By definition, they are purely venous
with no arterial component, meaning they are slow-flow, low pressure
venous spaces. If they are in an area which is near the surface, they
will present as a soft fluid-filled mass which can be emptied by manually
compressing it or, if it is in an extremity, elevating the extremity
above the level of the heart. In infants and children, the lesion may
change in size or shape depending on position or even when the child
is crying, which increases venous pressure. Since they are low flow,
they will not have pulsation, nor will they show enlargement of the
vessels in the area. They are nearly always painless to the touch, although
when they become distended with blood following activity or when in
dependent position, aching, heaviness, or a feeling of pressure may
When a cavernous venous malformation is accessible to physical examination,
the diagnosis is usually obvious. Ultrasound examination will show fluid-filled
spaces with little or no flow, while CT and particularly MRI can confirm
the diagnosis with certainty.
As in arteriovenous malformations, these lesions will grow along with
the child until maturity; unlike hemangiomas, they will not go away
by themselves. If symptoms are absent or minimal, treatment is not required,
nor is any limitation of normal activities. The patient may periodically
experience episodes of localized pain in the malformation with associated
signs of inflammation (redness, swelling, warmth); this is nearly always
due to localized clotting (thrombosis) within these slow-flow spaces
(blood tends to clot when it is not flowing). These are benign localized
clots, not the type of blood clot which put the patient at risk for
pulmonary embolism or stroke; treatment consists of warm soaks and anti-inflammatory
medication. The symptoms can be expected to resolve in one or two weeks.
Treatment should be directed at relief of symptoms, rather than complete
eradication of the malformation, which is often not possible without
disfiguring (and unnecessary) surgery. Local measures such as support
stockings, ace bandages, or elastic sleeves may show a significant reduction
in venous distention and pain when used during strenuous activity. Surgical
removal may be indicated when the malformation is localized and accessible
without excessive loss of normal tissue; it is essential for detailed
imaging studies (CT, MRI) to be obtained prior to any planned surgery,
as the visible or palpable mass may be the “tip of the iceberg”,
and a simple operation can quickly become
Direct embolization, a form of sclerotherapy, can be effective at shrinking
these venous malformations and reducing or eliminating symptoms. Under
sedation or anesthesia, the malformation is entered directly with a
small catheter and radiographic contrast (x-ray dye) is injected while
observing under fluoroscopy. This will show the true extent of the lesion
and whether it connects to the normal veins in the region, an important
piece of information for planning a safe procedure. Once the size and
volume of the malformation is determined, the embolic agent (ethanol
or sodium tetradecyl sulfate are the commonest) is directly injected,
again under visual x-ray guidance. Often a venogram, or radiologic study
of the normal veins in the region, will be performed prior to the embolization.
In some patients with venous malformations, an associated congenital
abnormality is an absence or underdevelopment of the normal venous system
in the area, meaning that the only route for blood draining from the
extremity is through the malformation. Blocking off the malformation
with embolization would then make the symptoms much worse.
Following a direct embolization procedure, the area will likely appear
enlarged and possibly more uncomfortable for a period of two to three
weeks. This is due to the inflammatory process deliberately caused in
order to clot the abnormal venous spaces.
As the clot is reabsorbed and replaced with connective tissue, the malformation
will typically show shrinkage over a period of six to eight weeks. It
is common for multiple procedures to be required to achieve a maximum
effect in shrinking the malformation and
eliminating symptoms of pain and swelling. In certain parts of the body,
particularly the calf and forearm, treatment must be staged in order
to avoid excessively increasing pressure in the closed tissue compartments
found in these locations (compartment syndrome). Other possible problems
following direct embolization include skin ulceration and bleeding,
both usually minor and controlled with topical treatment.
One of the commonest forms of venous malformation, despite its exotic-sounding
name, is Klippel-Trenaunay Syndrome, which generally involves a singe
extremity (usually the leg), and includes over- or undergrowth of the
involved limb, varicose veins, and a port wine stain (capillary venous
malformation) over the involved part. There is a wide range of signs
and symptoms ranging from minimal, with unilateral mild varicose veins,
to severe forms which can cause significant disability. Like the other
malformations, this condition is congenital but not genetically transmitted,
and is rarely seen in other family members. Treatment is usually for
symptoms only, and usually includes support stockings and local skin
care over large superficial veins. In some children with significant
limb length discrepancy, carefully timed fusion of the growth plate
(epiphysis) at the knee is performed in order to minimize the length
discrepancy when full growth is attained. One important caution in treating
patients with this syndrome is to determine the status of the deep venous
system either by MR venography or contrast venography prior to considering
the stripping, removal, or ablation of symptomatic veins. Approximately
one third of patients with this syndrome will have abnormalities of
the deep veins which would make vein stripping inadvisable or even dangerous.
An unusual variant of Klippel Trenaunay Syndrome is one in which there
is an arterial component to the malformation; this is termed Parkes
Weber Syndrome, and these patients may benefit from arterial embolization
to reduce the pressure in the abnormal veins. MRI studies will generally
allow this diagnosis to be made accurately.
The lymphatic system is part of the body’s circulatory system,
but rather than carrying blood, it picks up the tissue fluid that normally
escapes into the tissues and returns it to the general circulation through
a series of tiny channels. In addition to scavenging this fluid, it
serves an important immunologic function by delivering bacteria and
other pathogenic agents to the lymph nodes, where the cellular immune
response is initiated
Lymphatic malformations may occur alone or in combination with venous
malformations. The three broad categories of lymphatic malformation
are the cystic type (cystic hygroma), usually seen in infants and children,
more diffuse malformations which often have superficial skin involvement,
and syndromes involving underdevelopment of the lymphatic system in
an anatomic region (congenital lymphedema syndromes). The cystic malformations
usually occur in the neck and present as a soft tissue mass;
treatment is by excision or by drainage and injection of a sclerosing
agent. The more diffuse form is more commonly seen in adults, who develop
small blister-like lesions (vesicles) which can leak clear lymphatic
fluid and tend to develop multiple episodes of infection and inflammation
(cellulitis). Treatment is difficult and consists of sclerotherapy,
local care, and in some cases surgical removal. Congenital lymphedema
syndromes are uncommon, but may be seen in association with some genetic
abnormalities such as Turner’s Syndrome. There is no specific
treatment other than compression garments and lymphatic massage.
If you’ve read this far, you now know more about hemangiomas
and vascular malformations than 95% of practicing physicians. As you
have seen, these represent a wide range of conditions which can affect
all age groups and range in severity from trivial to extremely serious.
The key points to remember are that proper diagnosis is essential, treatment
should be by individuals with specific expertise in this field, and
that these are generally benign conditions in otherwise healthy individuals,
so that any proposed treatment should be directed at treating symptoms
with a minimal degree of risk and discomfort.
If you have any questions regarding these conditions in general or about
yourself or a family member, please feel free to contact me:
Robert J. Rosen, M.D.
Lenox Hill Heart and Vascular Institute
130 East 77th Street
New York, N.Y. 10021
Tel. 212 434 2606