Giant Cell Tumor of Bone (Osteoclastoma)
Giant cell tumor of bone is characterized by massive destruction of the end of a long bone. The sites most commonly struck by this tumor are the the distal end of the femur and the proximal end of the tibia (therefore at the knee). The tumor is often coated by new bony growth. It causes pain, restricts movement, and is usually cancerous. Treatment is by surgery, usually followed by chemotherapy. There is no evidence that the tumor cells themselves are capable of bone destruction; instead, the tumor cells stimulate the formation of cells that function like osteoclasts and resorb bone. The term “giant cell” reflects the fact that osteoclasts are large multinucleate cells (cells with more than one nucleus) that appear very large when viewed magnified through a microscope. Giant cell tumor of bone is also often called osteoclastoma, reflecting the long-held incorrect view that the tumor cells are themselves osteoclasts.