[Histopathological study of the effect of preoperative chemotherapy on osteosarcoma].

A total of 70 patients with conventional osteosarcoma underwent preoperative chemotherapy, and here we report the histopathological effects of the chemotherapy on the tumors. The changes in the tumors since pre-chemotherapy observed at resection were classified as: (1) non-degeneration, (2) degeneration, (3) coagulation necrosis, (4) granulation, (5) fibrosis, or (6) osteosclerosis, It was thought that any coagulation necrosis was due to ischemia, while any degeneration in the tumor tissue was mainly caused by the chemotherapy. Coagulation necrosis was found at the center of the tumor, while degeneration, fibrosis, and osteosclerosis tended to be present mainly at the periphery. Coagulation necrosis was less prominent in these patients with a longer period between preoperative chemotherapy and resection. The above results suggest that coagulation necrosis was not a change caused directly by the chemotherapy, and there is a possibility that the tumor cells in these regions survived until just before resection. Accordingly, when evaluating the effects of preoperative chemotherapy, it may be inappropriate to include any area of coagulation necrosis in the calculation of the necrotic ratio.