- A type of bone tumor characterized by massive destruction of bone near the end (epiphysis) of a long bone. The site most commonly struck by this tumor is the knee — the far end of the femur and the near end of the tibia. The tumor is often coated by new bony growth. It causes pain and restricts movement. 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 "osteoclastoma" reflects the long-held incorrect view that the tumor cells are themselves osteoclasts. Osteoclastoma is also called giant cell tumor of bone or malignant giant cell tumor. The tumor is full of osteoclasts which are large multinucleate cells (cells with more than one nucleus) that look gigantic when viewed magnified through a microscope. A tumor termed aggressive osteoblastoma arises predominantly in the spine or ribs. It is locally aggressive, as its name suggests. It may become malignant but does not metastasize. It tends to recur near its original location.
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* * *n.a rare tumour of bone, caused by proliferation of osteoclast cells.
* * *os·teo·clas·to·ma (os″te-o-klas-toґmə) [osteoclast + -oma] giant cell tumor of bone.
Medical dictionary. 2011.