抄録
We present a case of malignant giant cell tumor of bone (GCT) that developed after surgery alone. Malignancy develops in approximately 1-2% of patients with giant cell tumors of bone, and is classified as either primary or secondary. Primary malignant GCT is extremely rare, and secondary malignant GCT typically occurs after radiotherapy, but can rarely occurs without radiotherapy. A 27-year-old male with GCT of bone in the left distal femur was treated by curettage and autologous bone grafting. One year later, the tumor recurred and reoperation was performed. Two years after the second surgery, malignant change and pulmonary metastasis occurred. Despite chemotherapy, the patient died one year after development of malignant GCT. This patient was younger than is usual for cases of this type, and the period between recurrences was shorter than usual. Clinicians should be mindful about malignant transformation in cases with giant cell tumor of bone showing repeated recurrence.