Malignant giant cell tumor of bone

Giant cell tumors (GCTs) are primary locally aggressive bone tumors that represent 5% of all bone neoplasms. They have a female predominance and they are most common in patients aged 20 to 40 years. In Oriental and Asian populations incidence may reach 20% of bone neoplasms while it is more uncommon in Caucasians. Pain is the most common presenting symptom while pathologic fractures may occur in 11-37% of the cases. Distal femur, proximal tibia and distal radius are the most common sites involved with 50% of the cases diagnosed around the knee area (Figure 1). These neoplasms are characterized by osteoclast-like giant multinucleate cells (Figure 2). Thus, radiographically they appear as pure osteolytic eccentric lesions of the epiphysis extending to the articular surface or the diaphysis (Figure 3). GCTs are usually highly destructive solitary lesions commonly extending to the surrounding soft tissue, however 1% to 2% may simultaneously or sequentially be multicentric. Although classified as primary benign bone tumors, in 1-3% of GCTs spontaneous transformation to a high-grade Abstract