angiosarcoma: a rare malignant neoplasm arising from vascular tissue; usually occurs in the breast and skin and is believed to originate from the endothelial cells of blood vessels
malignant tumor: a tumor that is malignant and tends to spread to other parts of the body
cloud chamber: apparatus that detects the path of high-energy particles passing through a supersaturated vapor; each particle ionizes molecules along its path and small droplets condense on them to produce a visible track