Skin angiosarcoma is a rare and aggressive type of cancer that begins in the cells lining blood vessels and lymphatic vessels in the skin. This disease primarily affects older adults and often appears on the head and neck, where it can look deceptively like a bruise that refuses to heal.

How Common Is Skin Angiosarcoma?

Skin angiosarcoma is extremely rare. In the United States, approximately one person per million is diagnosed with angiosarcoma each year. When we look at all types of soft tissue cancers, angiosarcomas make up only about one to two percent of cases. Among angiosarcomas, the skin form is the most common, representing about 60 percent of all angiosarcoma cases.^[1][2]

The disease shows a clear preference for certain age groups and locations on the body. Approximately 85 percent of skin angiosarcoma cases occur in people over 60 years old, with the average age at diagnosis being around 71 years. While the condition can affect anyone, it is slightly more common in men than women. Most cases appear on the head and neck, particularly the scalp and upper forehead, though the disease can also develop on the breast or other parts of the body.^[3][4]

Interestingly, the pattern of who gets skin angiosarcoma is changing over time. For people younger than 50, the rates are actually decreasing. However, for those over 70 years old, the incidence is rising. Additionally, more women are being diagnosed with angiosarcoma, likely because radiation therapy for breast cancer has become more common, and this treatment is a known risk factor for developing the disease years later.^[6]

What Causes Skin Angiosarcoma?

The exact cause of most skin angiosarcomas remains unknown. Scientists understand that the disease begins when endothelial cells, which are the cells that line the inside of blood vessels and lymphatic vessels, start to grow and multiply in an abnormal, uncontrolled way. These cells form the barrier between the bloodstream and surrounding tissues. In angiosarcoma, instead of dying naturally as normal cells do, these abnormal cells keep dividing and creating new, malformed blood vessels that eventually develop into tumors.^[1][2]

While the precise trigger for this abnormal cell behavior is unclear, researchers have identified that the disease may involve problems with the regulation of new blood vessel formation, a process called angiogenesis. Studies have found that many angiosarcomas show overexpression of vascular endothelial growth factor or VEGF, a protein that normally helps control blood vessel growth. Additionally, mutations in certain genes like TP53 and those in the RAS pathway have been found in some tumors, suggesting these genetic changes might contribute to cancer development.^[6]

There is also evidence that angiosarcoma can occasionally run in families. Scientists have discovered that people with changes in a gene called POT1 may develop angiosarcoma of the heart, and this genetic mutation can be passed from parents to children. However, this hereditary form is quite rare.^[3]

Who Is at Higher Risk?

While skin angiosarcoma can develop in anyone without warning, certain factors significantly increase a person’s chances of developing this cancer. Understanding these risk factors can help people and their doctors stay alert for early signs.

One of the strongest risk factors is previous exposure to radiation therapy. People who received radiation treatment for another type of cancer, particularly breast cancer, face an elevated risk of developing angiosarcoma years or even decades later. This type of cancer, called radiation-induced angiosarcoma, typically appears eight to ten years after the radiation treatment but can take even longer to develop. The affected area is usually where the radiation was directed.^[2][3]

Chronic swelling of the arms or legs, known as lymphedema, is another significant risk factor. This condition involves the buildup of lymph fluid in tissues, causing persistent swelling. Lymphedema often occurs after surgical removal of lymph nodes, which is sometimes done as part of breast cancer treatment, such as radical mastectomy where the breast and all lymph nodes under the arm are removed. When angiosarcoma develops in these chronically swollen areas, it’s sometimes called Stewart-Treves syndrome. About five percent of all angiosarcomas are associated with chronic lymphedema.^[2][7]

Exposure to certain chemicals in the environment or workplace can also raise the risk of developing angiosarcoma, though this more commonly affects internal organs like the liver rather than the skin. These harmful substances include vinyl chloride (used in plastic manufacturing), arsenic, thorium dioxide (a contrast agent once used in medical imaging but no longer in use), and certain herbicides. The frightening aspect of chemical exposure is that angiosarcoma may not appear until 10 to 40 years after contact with these substances.^[2][7]

Certain rare genetic conditions also increase risk. These include neurofibromatosis 1, mutations in the BRCA1 or BRCA2 genes (which are better known for increasing breast cancer risk), Maffucci syndrome, and Klippel-Trenaunay syndrome. People with foreign materials in their bodies, such as surgical mesh (Dacron), shrapnel, steel, or plastic implants, may also face a slightly higher risk, though this is uncommon.^[6][7]

What Are the Symptoms?

Skin angiosarcoma can be tricky to recognize because it often looks like something far less serious. The most common appearance is a raised area of skin that resembles a bruise. Unlike a normal bruise that fades over time, this bruise-like mark grows larger and doesn’t go away. It may start as a small, reddish or purplish patch on the skin, often on the scalp, face, or neck.^[1][2]

As the disease progresses, the affected area may change in appearance. What begins as a flat, bruised-looking spot can evolve into raised lumps or nodules. These lesions may be blue, black, or purple in color. One particularly concerning feature is that these areas bleed very easily when scratched, bumped, or even touched lightly. Some people notice that the skin around the lesion becomes swollen.^[1][7]

In its early stages, skin angiosarcoma may appear as a single spot or multiple spots scattered across an area. The lesions tend to spread and grow rapidly, which makes it difficult to determine where the cancer ends and healthy tissue begins. This ill-defined spreading pattern is one of the challenging aspects of treating the disease. Some lesions develop into open sores that refuse to heal, continuing to grow instead.^[7]

Pain is not always present with skin angiosarcoma. Many people with lesions on their skin report that the areas don’t hurt at all. However, some individuals do experience tenderness or discomfort in the affected region. When angiosarcoma affects the breast, it often presents as swelling of the breast tissue with bluish discoloration of the skin, sometimes without a distinct lump that can be easily felt.^[2][7]

Because skin angiosarcoma is aggressive and spreads easily, some people may experience symptoms related to the cancer spreading to other parts of the body. The most common sites where skin angiosarcoma spreads are the lungs and liver. When cancer reaches these organs, people might notice symptoms like unexplained fatigue, difficulty breathing, cough, weight loss without trying, or pain in the upper abdomen. Spread through the lymphatic system or bloodstream occurs in approximately 16 to 35 percent of patients.^[6][9]

Can Skin Angiosarcoma Be Prevented?

Because the exact cause of most skin angiosarcomas is unknown, there is no guaranteed way to prevent the disease. However, understanding risk factors allows people to take some steps that may reduce their chances of developing this cancer or catch it early when treatment is most likely to be effective.

For people who need radiation therapy for cancer treatment, the benefits of this treatment in fighting the primary cancer far outweigh the small risk of developing angiosarcoma years later. However, patients who have received radiation therapy should be aware of this potential long-term risk and remain vigilant about examining the treated area for any unusual changes in the skin. Regular follow-up appointments with healthcare providers are important for monitoring.^[2][3]

Managing lymphedema properly is another important preventive measure. People who have chronic swelling in their arms or legs, especially after cancer surgery, should work with their healthcare team to control the swelling through compression garments, elevation, massage, and other recommended treatments. Keeping lymphedema under control may help reduce the risk of developing angiosarcoma in the affected limb.^[2]

Avoiding exposure to harmful chemicals is crucial, particularly in occupational settings. People who work with vinyl chloride, arsenic, or other toxic substances should follow all safety protocols, use proper protective equipment, and ensure good ventilation in work areas. Employers should maintain safe working conditions and provide necessary training and equipment to minimize chemical exposure.^[2][7]

Given that sun exposure may contribute to skin angiosarcoma on the head and neck, protecting skin from excessive ultraviolet radiation makes sense as a general cancer prevention strategy. This includes wearing hats, using sunscreen on exposed areas like the scalp (especially for people with thinning hair), seeking shade during peak sun hours, and avoiding tanning beds.^[6]

Perhaps most importantly, people should pay attention to their bodies and seek medical evaluation for any persistent skin changes. Any bruise-like mark that doesn’t fade after a few weeks, any sore that won’t heal, any lump that continues to grow, or any area that bleeds easily should prompt a visit to a healthcare provider. Early detection of skin angiosarcoma, while the tumor is still small and localized, offers the best chance for successful treatment.^[1]

How Does Skin Angiosarcoma Affect the Body?

Understanding what happens in the body when skin angiosarcoma develops helps explain why this disease is so dangerous and difficult to treat. The process begins at the cellular level, in the thin layer of endothelial cells that line blood vessels and lymphatic vessels throughout the skin.

Normally, endothelial cells are carefully controlled. They divide when needed to repair damaged vessels or create new ones during wound healing, then stop dividing when their job is done. Old or damaged cells die off through a natural process. In angiosarcoma, something goes wrong with these control mechanisms. The endothelial cells begin to multiply without stopping and fail to die when they should. Instead, they accumulate and start forming abnormal, chaotic networks of blood vessels.^[2][9]

These abnormal vessels don’t work like normal blood vessels. They’re fragile and leak easily, which is why angiosarcoma lesions bleed so readily when bumped. The tumor cells also produce substances that stimulate even more blood vessel growth, creating a vicious cycle. This process is driven in part by overproduction of vascular endothelial growth factor, or VEGF, which normally helps regulate blood vessel formation but becomes overactive in many angiosarcomas.^[6]

As the tumor grows, it doesn’t respect normal tissue boundaries. Unlike some cancers that grow as a defined lump, angiosarcoma tends to infiltrate surrounding tissues in an irregular pattern. Finger-like projections of cancer cells extend into healthy tissue, making it extremely difficult to tell where the tumor ends. This infiltrative growth pattern is why surgeons often struggle to remove all the cancer even when they take wide margins of tissue around the visible tumor.^[7][9]

Skin angiosarcoma is highly prone to spreading, or metastasizing. Cancer cells can break away from the original tumor and travel through blood vessels or lymphatic vessels to distant parts of the body. Once these cells reach other organs, particularly the lungs or liver, they can establish new tumors. This ability to spread quickly is one reason why skin angiosarcoma has such a poor prognosis. Even when the original tumor on the skin appears small, microscopic spread may have already occurred.^[4][9]

The tumor can also recur locally, meaning it grows back in the same area even after treatment. This happens when cancer cells remain in the tissue despite surgery or other treatments. Local recurrence rates for skin angiosarcoma are unfortunately high, with many patients experiencing return of the tumor in the same region within months to years after initial treatment.^[4][9]

Recent research has revealed some of the molecular and genetic changes that drive angiosarcoma. Beyond VEGF overexpression, many tumors harbor mutations in genes like TP53, which normally acts as a brake on cell division and tumor formation. When TP53 is mutated, cells lose this important safety mechanism. Changes in the RAS pathway, which controls cell growth signals, have also been identified in some angiosarcomas. Understanding these molecular abnormalities is helping researchers develop new targeted treatments.^[6]