Hepatic Angiosarcoma : Risk Factors

Hepatic angiosarcoma has been associated with exposure to chemical carcinogens, including:

• Thorotrast given for radiographic studies
• Arsenic in insecticides and contaminated ground water
• Vinyl chloride in rubber and plastic industries
• Androgenic anabolic steroids

THOROTRAST- a radiopaque contrast medium containing thorium dioxide - was widely used in radiographic studies from 1928 to around 1955. It produced excellent images due to high degree of radioopacity. Once it is administered into the circulation, it is taken up by the cells of reticuloendothelial system and is stored in liver, spleen, bones, and lymph nodes.

It is radioactive and emits high-energy alpha particles as it decays slowly (half-life estimated to be about 400 years), subjecting internal organs to a life-time of harmful radiation.

The use of thorotrast was discontinued in the 1950's after it was found to increase the risk of hepatic fibrosis and several malignancies, including hepatic angiosarcoma, hepatocellular carcinoma, cholangiocarcinoma, and leukemias. The latent period is 20 to 30 years.

Historically, about 25% of primary hepatic angiosarcomas were linked to occupational or medicinal exposure to carcinogens. However, with declining use of these carcinogens due to increased awareness, most current cases are idiopathic or linked to anabolic steroid use.

There are no histopathological differences between idiopathic tumors and those induced by chemical carcinogens. Premalignant changes in the liver exposed to thorotrast and other similar carcinogens include hyperplastic hepatocytes, sinusoidal dilatation, mild atypia of lining endothelium, and fibrosis. Image copyright: pathorama.ch