hemangioendothelioma
noun
he·man·gio·en·do·the·li·o·ma
variants:
or chiefly British haemangioendothelioma \ -jē-ō-ˌen-dō-ˌthē-lē-ˈō-mə 
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plural hemangioendotheliomas
also hemangioendotheliomata\ -mət-ə
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Medical Definition of hemangioendothelioma
: an often malignant tumor originating by proliferation of capillary endothelium