Sarcomas on Bone Infarcts or Necrosis
There are rare cases in which sarcoma — malignant fibrous histiocytoma, fibrosarcoma, osteosarcoma, angiosarcoma (Fig. 505) — develops in the area of an old bone infarct, due to decompression air emboli or of unknown origin. These sarcomas have been observed only in the femur and in the tibia (see chapters on tumors listed above). Exceptionally, there may be a sarcoma occurring on a benign tumor, for example a giant cell tumor, submitted many years earlier to curettage and bone grafting, or on an old calcified chondroma. These sarcomas may have originated from the reactive cells around a necrotic calcified material, present for many years.