Malignant tumors which arise from preexisting lipoma and exhibit pronounced fatty elements have been described not infrequently since the original articles of Virchow1 in the middle of the last century. The contributions of Robertson,2 in 1916, and that of Seids and McGinnis,3 in 1926, summarize the present knowledge of these tumors. It is noteworthy that these reports are concerned only with those tumors which were found perirenally or in the fascial planes of the extremities.
So far as a reasonable search of the literature will disclose, the only instances of primary liposarcoma of bone seen were the three cases reported by Stewart4 from the Memorial Hospital, New York, in 1931. Stewart concluded from circumstantial data that his tumors were primary in the bone, and stated "we are not in a position of absolute certainty in stating this." Again, he said: "The only constituent of bone or