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Robert J. Rosen, M.D.
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.
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
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.
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 cycle.
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.
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
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%.
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.
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.
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.
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.
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;
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.
Robert J. Rosen, M.D.
Tel. 212 434 2606
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