Multiple-organ involvement at time of diagnosis is common and makes it difficult to ascertain origin and how to treat it.

[7] The cause of angiosarcoma is not known, though several risk factors are known, such as chronic lymphedema, radiation therapy and various chemicals such as arsenic and vinyl chloride.

[3] Angiosarcoma can be seen on MRI, CT and ultrasound scans, but it is usually difficult to discern it from other cancers, requiring confirmation of diagnosis by biopsy and immunohistochemical analysis.

Because these cancers arise from the cells lining the blood or lymphatic vessels, they can easily metastasize to distant sites, particularly the liver and lungs.

[3] Angiosarcoma in the skin (usually the head or neck and specifically the scalp) with no underlying risk factors such as lymphedema or radiation therapy.

[citation needed] Also called Stewart-Treves syndrome, it is a lymphangiosarcoma resulting from chronic lymphedema, swelling due to the build up of lymphatic fluid.

[citation needed] This refers to angiosarcoma of the breast without underlying causes such as radiation therapy or lymphedema.

However it varies greatly depending on whether or not the tumor has metastasised, some individuals may be rid of the disease following surgery, chemotherapy and radiation therapy.

[7] Due to the non-specificity of symptoms and rarity of the disease it is often missed by doctors and initial diagnosis may be delayed.

Prognosis is generally very poor with a mean survival rate of three months to four years following diagnosis.

Despite being associated with arsenic, vinyl chloride, thorotrast and other chemicals, 75% of liver angiosarcomas have no known cause.

If symptomatic it often presents with non-specific liver related symptoms such as abdominal pain, jaundice, fatigue, unintended weight loss and distension.

[3] Cardiac angiosarcoma may present with shortness of breath, chest pain (46%), weight loss, anemia-like symptoms,[12] low blood pressure and syncope.

[3] Angiosarcoma develops when damage to the DNA of endothelial cells causes them to divide uncontrollably and prevents programmed death.

Some studies suggest a link between AIDS and angiosarcoma though this may be due to misdiagnosed Kaposi's sarcoma.

[5] The marker CD31 is often considered the gold standard for angiosarcoma diagnosis due to its high sensitivity and specificity.

It is rapidly fatal and metastatic and can present with anything from nonspecific signs to imminent death from tumor rupture.