[Osteosarcoma developing after radiation and chemotherapy for primary mediastinal seminoma]

This report presented an osteosarcoma arising from the same field after radiation and chemotherapy without surgery for primary mediastinal seminoma. A 45-year-old man had received from June 1979 to August 1981 irradiation and chemotherapy for the anterior-mediastinal seminoma. Since then he was been without evidence of disease for five years. In March 1987, he had suffered from an advanced tumor extending from the neck and the mediastinum to the right anterior chest wall. Further irradiation combined with thermotherapy were performed but without improvement. He was thereafter seen and admitted July 23 1987 to our hospital with complaint of back pain. Needle biopsy specimen revealed chondrosarcoma. Despite chemotherapy with CDDP, he died four months later after admission. Pathological finding of his autopsy revealed a widely invading osteosarcoma extending to extra- and intrathorax and the neck without evidence of germ cell component. To explain the pathogenesis of the secondarily developing osteosarcoma, two hypotheses are offered; 1. Malignancy of mesenchymal component in germ cell tumor. 2. Radiation-induced osteosarcoma. The latter hypothesis appears to be the most probable pathogenesis from his autopsy. These findings suggest that a long survival patient with malignant germ cell tumor after therapy should be never considered as being free from a potential risk of secondarily developing malignancy.