1. Two cases of malignant hemangioendothelioma of bone are presented, and the world's literature is reviewed. In all, there are thirty-four adequately documented cases of this rare primary bone tumor.
2. The clinical and roentgenographic features are non-specific.
3. The histological characteristic of this lesion is an overproduction of atypical endothelial cells that frequently form anastomosing vascular clefts.
4. Prognosis and treatment are discussed.