[Giant-cell tumor of the bone].

The giant-cell tumor of bone (GCT) is an aggressive benign, potentially malignant lesion, which biological behaviour is unpredictable. Its aggressivity is usually increasing through the recurrences and is related to the mitotic activity, the excessive metalloproteinase expression and to the alterations in different oncogens of the tumor cells. Statistically, 80% of the GCT-s have a benign course, with a local recurrence rate of 10-50%; about 10% of GCT-s undergo malignant transformation through their recurrences and 1-4% give pulmonary metastases even in case of a benign histology. Despite of the frequent recurrences, adequate treatment results in 96% to 98% cure in patients with GCT. The goal of surgery should be both in primary and recurrent cases: joint-sparing and careful curettage with use of adjuvants (bone cement and phenol, etc.) for decreasing the rate of recurrences. Resection is only in case of extensive joint destruction or malignancy indicated. Radiotherapy with modern supervoltage equipment minimalized the occurrence of secondary malignant transformation, however, its use is only in locations difficult for surgery (vertebra, sacrum, pelvis) recommended.