Giant cell tumor of the bone (also called giant cell myeloma or osteoclastoma) is a relatively uncommon tumor. It is characterized by the presence of multinucleated giant cells (osteoclast-like cells). These tumors are generally benign. In most patients, the tumors are slow to develop, but may recur locally in as many as 50% of cases. Metastasis to the lungs may occur.
Giant cell tumor of the bone accounts for 4-5% of primary bone tumors and 18.2% of benign bone tumors. Giant cell tumors are mostly benign, however 5-10% of patients may have a malignant tumor.
Patients usually present with pain and limited range of motion caused by tumor's proximity to the joint space. There may be swelling as well, if the tumor has been growing for a long time. Some patients may be asymptomatic until they develop a pathologic fracture
at the site of the tumor.
Patient may also experience nerve pain which feels like an electric shock.
On x-ray, giant cell tumors (GCTs) have a metaepiphyseal location and grow to the articular surface of the involved bone. Radiologically the tumours show characteristic 'soap bubble' appearance. They are distinguishable from other bony tumors in that GCTs usually have a non-sclerotic and sharply defined border. Because giant cell tumors are known to metastasize, when the diagnosis of giant cell tumor is suspected, a chest x-ray or CT
may be needed. MRI can be used to assess intramedullary and soft tissue extension.
Surgery is the treatment of choice if the tumor is determined to be resectable. Curettage
is a commonly used technique.
Patients with tumors that are not amenable to surgery are treated with radiation therapy. The situation is complicated in a patient with a pathological fracture. It may be best to immobilize the affected limb and wait for the fracture to heal before performing surgery.
Other bone tumors with giant cells
A number of tumors have giant cells, but are not true benign giant cell tumors. These include, aneurysmal bone cyst
, simple bone cyst
, osteoid osteoma
, giant cell reparative granuloma
, and brown tumor