- Abstract -

Giant cell bone tumors (osteoclastoma, myeloplax tumor) are benign tumors, although they are locally aggressive. They represent between 5% and 7% of primary bone tumors. The most common occurrence sites are near joints (commonly the knee joint) involving the ends of long bones: proximal tibia, distal femur, distal radius. The onset age of the disease is between twenty and thirty years, with a slight predominance of the female gender. The diagnosis is based on clinical examination, X-rays of the bone, CT and MRI. Some authors suspected an angiogenetic origin of the tumor and another possible factor in the etiology is genetic predisposition. Giant cells arise by transformation of circulating monocytes, many of them later becoming active osteoclasts.

A rare complication of these tumors, but with high lethal potential, is the malignant transformation (primary and secondary malignancies). The best treatment is surgery, with or without area reconstruction. Another therapeutic method is cryosurgery. In the treatment of tumor metastasis (commonly occurring in the lungs), chemotherapy and surgery are indicated.

Key words: bone tumor, giant cells, locally aggressive, metastasis, circulating monocytes, surgery.