Primary angiosarcoma of the brain in a child.

We describe a pediatric case of primary angiosarcoma of the brain displaying striking intravascular papillary pattern, consistent with the "Dabska tumor," often in continuity with a massive, multifocal intravascular papillary endothelial hyperplasia. The tumor contained small hemangioma and obliterated dysplastic arteries as well as very large thin-walled veins. The surrounding brain tissue showed scattered telangiectasias, conglomerates of calcified dysplastic arteries, old hemorrhages and gliosis. Colocalization of these lesions suggests the development of a papillary angiosarcoma in the pre-existing vascular malformation. Although never reported, the possibility of a malignant transformation of endothelial papillary hyperplasia also should be considered in this case.