ConditionSkin, hair & nails
Venous Malformation
A venous malformation (VM) is a cluster of abnormally formed, widened veins in the skin, muscle or deeper tissue that is present from birth. It looks like a soft, squashy, bluish swelling that gets bigger when the area hangs down or with straining and shrinks when raised or squeezed. Unlike a hemangioma, it never goes away on its own and tends to grow slowly with the child. Small clots inside can cause pain. Compression, sclerotherapy, surgery and newer targeted drugs control symptoms.
Also called: VM, venous anomaly, slow-flow vascular malformation, cavernous hemangioma (outdated and incorrect name)
At a glance
- What it is
- A slow-flow birth defect of veins, the most common type of vascular malformation.
- Appearance
- Soft, compressible, blue or purple swelling, or a deeper lump with normal skin over it.
- Behavior
- Present at birth, grows with the child, may enlarge in puberty or pregnancy. Never disappears on its own.
- Symptoms
- Swelling, heaviness, pain from small clots (phleboliths), and sometimes bleeding.
- Diagnosis
- Ultrasound with Doppler and MRI.
- Treatment
- Compression, anti-clotting medicine for pain, sclerotherapy, surgery, laser and sirolimus.
When to get help
Call 911 or go to the ER
- Heavy bleeding from a malformation that does not stop with 10 minutes of firm pressure
- A malformation in the mouth, tongue or neck that causes difficulty breathing or swallowing
- Chest pain or sudden breathlessness, especially with a large limb malformation (possible blood clot in the lungs)
See a doctor within a day or two
- Sudden, severe pain, hardness and tenderness in a malformation that does not settle in a few days
- Rapid enlargement, red hot skin or fever
- Unexplained bruising or bleeding in someone with a large or extensive malformation
Book a routine appointment
- A soft bluish lump in a baby or child that swells when crying or when the limb hangs down
- Aching, heaviness or swelling that limits sport, walking or work
- A malformation that is growing during puberty or pregnancy
- Bulging or pain near a joint, such as the knee
What a venous malformation is
Vascular anomalies are divided into two groups:
- Vascular tumors, such as infantile hemangioma, are made of growing cells. They typically appear in the first weeks of life, grow quickly, then shrink.
- Vascular malformations are errors in how blood or lymph vessels formed before birth. They do not shrink.
A venous malformation is a malformation of veins. The walls of the affected veins lack normal smooth muscle support, so they stretch into spongy spaces where blood moves slowly. That slow flow lets small clots form, which can harden into calcified stones called phleboliths.
Venous malformations are the most common vascular malformation. Many are caused by a change (mutation) in the TEK (TIE2) or PIK3CA gene that happens in the affected tissue only, so they are usually not inherited. Rare inherited forms and syndromes exist, such as blue rubber bleb nevus syndrome and glomuvenous malformations.
Where they occur
Venous malformations can occur anywhere, but common sites are:
- head and neck, including lips, cheeks, tongue and airway
- arms and legs, often extending into muscle or joints
- trunk
- rarely, gut or internal organs, which can cause bleeding and anemia
Symptoms
- a soft, squishy swelling that may be blue, purple or skin-colored
- enlargement when the area is lower than the heart, with exercise, crying or straining
- shrinking when raised or pressed
- aching and heaviness, often worse in the morning or after standing
- episodes of painful, firm, tender lumps from small clots, lasting days
- small hard pebbles felt inside (phleboliths)
- limb swelling or a difference in limb size
- reduced joint movement or joint bleeding when a malformation involves the knee or elbow
- bleeding from lesions in the mouth or gut
Venous malformation vs hemangioma
| Infantile hemangioma | Venous malformation | |
|---|---|---|
| When it appears | Usually in the first weeks after birth | Present at birth, may only be noticed later |
| Growth | Rapid in the first months, then shrinks over years | Grows slowly with the child, may expand at puberty or pregnancy |
| Feel | Firm, warm, rubbery | Soft, compressible, fills when dependent |
| Color | Bright red or bluish if deep | Blue or purple, or normal skin over a deep lesion |
| Treatment | Often none, or propranolol | Compression, sclerotherapy, surgery, sirolimus |
A venous malformation is sometimes wrongly called a "cavernous hemangioma". Using the correct term matters because the treatments are different. Lymphatic malformations and arteriovenous malformations, which have fast flow and feel warm or pulse, are other types of vascular malformation.
Diagnosis
- History and examination: when it appeared, how it changes with position, and a check for warmth or a pulse (which suggests an AVM).
- Ultrasound with Doppler: shows compressible channels with slow flow and phleboliths.
- MRI: the most important test, showing the full extent into muscle, joints and nearby structures. It guides treatment planning.
- Blood tests: D-dimer and fibrinogen. Large or extensive malformations can cause localized intravascular coagulopathy, where clotting factors are used up inside the malformation, causing raised D-dimer, low fibrinogen and a tendency to clot and bleed. A raised D-dimer also helps distinguish a VM from other malformations.
- Genetic testing of tissue may be used when targeted drugs are considered.
Care is best at a multidisciplinary vascular anomalies center.
Treatment
Treatment is aimed at symptoms. Small, painless malformations may only need monitoring.
Conservative care
- Compression garments for limb malformations reduce swelling, heaviness and clot pain.
- Elevation of the affected limb when resting.
- Aspirin or low-molecular-weight heparin can reduce painful clotting episodes and treat coagulopathy, especially before surgery. Do not give aspirin to children without medical advice.
- Pain relief: acetaminophen (paracetamol) or ibuprofen at the label dose during clot episodes.
Sclerotherapy
The main active treatment. An interventional radiologist injects a sclerosing agent (such as polidocanol, sodium tetradecyl sulfate, ethanol or bleomycin) into the malformation under ultrasound and X-ray guidance. It damages the lining, causing the channels to scar and shrink. Several sessions are often needed. Swelling for a few days afterwards is expected. Risks include skin injury, nerve injury and blood clots.
Surgery and laser
- Surgical removal for small, well-defined lesions, or after sclerotherapy to remove residual tissue. Complete removal of large malformations is often not possible without damaging normal structures.
- Laser treatment for superficial lesions in the skin, lips or mouth.
Medicines
Sirolimus, which blocks the overactive cell growth signal, can reduce pain, swelling, bleeding and coagulopathy in extensive malformations. Alpelisib, a PIK3CA inhibitor, is used for some PIK3CA-related conditions. These are prescribed by specialist centers.
Complications
- chronic pain and repeated clotting episodes
- limb length difference and muscle wasting
- joint damage from bleeding into the joint, leading to arthritis
- bleeding, including from the gut
- blood clots in deep veins and, rarely, in the lungs, mainly with large malformations
- coagulopathy causing bleeding during surgery or childbirth
- appearance concerns and psychological distress
Living with a venous malformation
Most people live full, active lives. Keep active with compression for sport, plan pregnancy with a specialist (blood thinners may be advised), and tell surgeons and anesthetists about the malformation and any coagulopathy. Hormonal contraception containing estrogen may worsen some malformations, so discuss options with your doctor.
Frequently asked questions
Is a venous malformation dangerous?
Most are not life-threatening. They cause swelling, pain and appearance concerns. Large or deep ones can cause clotting problems, bleeding, joint damage, or breathing and swallowing difficulty in the head and neck, so they need specialist care.
Will a venous malformation go away on its own?
No. Unlike infantile hemangiomas, venous malformations do not shrink with time. They grow in proportion with the body and may enlarge during puberty, pregnancy or after injury. Treatment can shrink them and control symptoms.
Why does my venous malformation hurt?
Pain usually comes from small blood clots forming in the slow-moving blood, which causes tender, firm lumps for several days. Swelling and stretching when the limb hangs down also causes aching. Compression garments and, in some cases, aspirin or heparin help.
How many sclerotherapy sessions will I need?
It varies. Small malformations may need one or two sessions, while larger or deep ones often need several, spaced weeks to months apart. Your interventional radiologist will review progress with ultrasound or MRI after each treatment.
Is a venous malformation cancer?
No. It is a benign birth defect of the veins and does not turn into cancer. It is not a tumor and does not spread. New, rapid growth or unusual features are still checked, to make sure the diagnosis is correct.
Sources
This guide was written from current patient and clinical guidance, including:
- International Society for the Study of Vascular Anomalies (ISSVA): Classification of Vascular Anomalies
- Society for Interventional Radiology: Vascular malformations
- Boston Children's Hospital Vascular Anomalies Center: Venous malformation
- Cincinnati Children's Hemangioma and Vascular Malformation Center: Venous malformations
- NORD: Venous Malformation