Giant cell tumors (GCTs) of bone typically present in adults between the ages of 20 and 50 with the symptoms of progressive pain and local swelling. Females are slightly more often affected than males. GCTs tend to arise in epiphyses of long tubular bones. The typical radiographic appearances are of geographical radiolucency and cortical thinning, without internal mineralization. GCTs represent 5% of all primary bone tumours. Although benign, GCTs are locally aggressive entities producing expansive and lytic lesions. We present the case of a young man with a GCT of his pelvis who could not be treated by previously described methods because of the size of the lesion, its location, and the effects it had on surrounding bony structures.