From time to time articles have appeared discussing vascular tumors arising in the bones, which have presented peculiarities resulting in their designation variously as pulsating sarcoma, bone aneurysms, hemangiosarcoma and hemangio-endothelioma, a variety of terms which indicate either that several different pathologic conditions may present similar characters, or that a single condition presents different features at different times and places. The present consensus seems to be that true bone aneurysms rarely, if ever, occur, and that most, if not all, of the growths under discussion represent merely malignant neoplasms with hemorrhagic softening. Oehler early noted that in such cases the tumor tissue might be difficult to find, persisting merely as a thin superficial layer. He assumed that the so-called bone aneurysms arise from hemorrhagic sarcomas of bone, the blood stream gradually washing out the sarcoma cells. Gaylord1 accepted this view, reporting a case in which only a small area