Image Description
The image shows fibroblastic osteosarcoma involving a rib in a 62 y/o female who received radiation therapy for recurrent breast cancer. The tumor showed only focal osteoid production. It has been noticed in some studies that the response of radiation-induced osteosarcoma to neoadjuvant chemotherapy (i.e. the extent of tumor necrosis) does not have prognostic significance, unlike in conventional osteosarcomas.