A 63-year-old man presented with a three-year history o f a slowly growing, painless mass in the right thigh. In the proceeding months , more rapid growth had resulted. He gave a history of being wounded in battle in Germany in 1945 (approximately 35 years previously), incurring a right femoral fracture with retained shrapnel in the soft tissues. Several months later, in England, he underwent a definitive repair with internal fixation and bone grafting. Thereafter, he reported no problems with the leg until the present episode. On physical examination, a large (approximately 10 x 20 cm), firm, movable, non-tender, posterolateral mass in the right thigh was noted. N o sinus tract was observed and the mass was no t pulsatile. The hematological and blood chemical studies were within normal limits. Roentgenograms of the right femur (Fig. 1) and addit ional special studies were obtained (see later). Surgical explorat ion was undertaken.