Malignant Giant Cell Tumor
摘要
Giant cell tumors are known to evolve into malignant tumors. McGrath (1972) classified such tumors into three types: primary, evolutionary, and secondary. “Primary” is for tumors that are malignant from outset, “evolutionary” for typical tumors that progress to a malignant form within a short period, and “secondary” for typical tumors that undergo sarcomatous changes after a relatively long symptom-free period and usually develop after irradiation (postirradiation malignancy).