hemangiosarcoma
noun
he·man·gio·sar·co·ma
variants:
or chiefly British haemangiosarcoma \ -jē-ō-sär-ˈkō-mə 
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plural hemangiosarcomas
also hemangiosarcomata\ -mət-ə
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Medical Definition of hemangiosarcoma
: a malignant hemangioma