Giant-cell tumor of bone

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Giant-cell tumor of bone_table_infobox_0

Giant-cell tumor of boneGiant-cell tumor of bone_header_cell_0_0_0
SpecialtyGiant-cell tumor of bone_header_cell_0_1_0 Oncology Q1785791?uselang=en#P1995Giant-cell tumor of bone_cell_0_1_1

Giant-cell tumor of the bone (GCTOB), is a relatively uncommon tumor of the bone. Giant-cell tumor of bone_sentence_0

It is characterized by the presence of multinucleated giant cells (osteoclast-like cells). Giant-cell tumor of bone_sentence_1

Malignancy in giant-cell tumor is uncommon and occurs in about 2% of all cases. Giant-cell tumor of bone_sentence_2

However, if malignant degeneration does occur, it is likely to metastasize to the lungs. Giant-cell tumor of bone_sentence_3

Giant-cell tumors are normally benign, with unpredictable behavior. Giant-cell tumor of bone_sentence_4

It is a heterogeneous tumor composed of three different cell populations. Giant-cell tumor of bone_sentence_5

The giant-cell tumour stromal cells (GCTSC) constitute the neoplastic cells, which are from an osteoblastic origin and are classified based on expression of osteoblast cell markers such as alkaline phosphatase and osteocalcin. Giant-cell tumor of bone_sentence_6

In contrast, the mononuclear histiocytic cells (MNHC) and multinucleated giant cell (MNGC) fractions are secondarily recruited and comprise the non-neoplastic cell population. Giant-cell tumor of bone_sentence_7

They are derived from an osteoclast-monocyte lineage determined primarily by expression of CD68, a marker for monocytic precursor cells. Giant-cell tumor of bone_sentence_8

In most patients, the tumors are slow to develop, but may recur locally in as many as 50% of cases. Giant-cell tumor of bone_sentence_9

Signs and symptoms Giant-cell tumor of bone_section_0

Patients usually present with pain and limited range of motion caused by tumor's proximity to the joint space. Giant-cell tumor of bone_sentence_10

Swelling may occur, as well, if the tumor has been growing for a long time. Giant-cell tumor of bone_sentence_11

Some patients may be asymptomatic until they develop a pathologic fracture at the site of the tumor. Giant-cell tumor of bone_sentence_12

They usually originate from the epiphysis of long bones, but in rare cases, they may arise from anterior arc of the ribs. Giant-cell tumor of bone_sentence_13

The symptoms may include muscular aches and pains in arms or legs and abdominal pain. Giant-cell tumor of bone_sentence_14

Patients may also experience nerve pain which feels like an electric shock due to weight bearing. Giant-cell tumor of bone_sentence_15

Diagnosis Giant-cell tumor of bone_section_1

The diagnosis of giant-cell tumors is based on biopsy findings. Giant-cell tumor of bone_sentence_16

The key histomorphologic feature is, as the name of the entity suggests, (multinucleated) giant cells with up to a hundred nuclei that have prominent nucleoli. Giant-cell tumor of bone_sentence_17

Surrounding mononuclear and small multinucleated cells have nuclei similar to those in the giant cells; this distinguishes the lesion from other osteogenic lesions which commonly have (benign) osteoclast-type giant cells. Giant-cell tumor of bone_sentence_18

Soap-bubble appearance is a characteristic feature. Giant-cell tumor of bone_sentence_19

Imaging Giant-cell tumor of bone_section_2

On X-ray, giant-cell tumors (GCTs) are lytic/lucent lesions that have an epiphyseal location and grow to the articular surface of the involved bone. Giant-cell tumor of bone_sentence_20

Radiologically the tumors may show characteristic 'soap bubble' appearance. Giant-cell tumor of bone_sentence_21

They are distinguishable from other bony tumors in that GCTs usually have a nonsclerotic and sharply defined border. Giant-cell tumor of bone_sentence_22

About 5% of giant-cell tumors metastasize, usually to a lung, which may be benign metastasis, when the diagnosis of giant-cell tumor is suspected, a chest X-ray or computed tomography may be needed. Giant-cell tumor of bone_sentence_23

MRI can be used to assess intramedullary and soft tissue extension. Giant-cell tumor of bone_sentence_24

Differential diagnosis Giant-cell tumor of bone_section_3

A number of tumors have giant cells, but are not true benign giant-cell tumors. Giant-cell tumor of bone_sentence_25

These include, aneurysmal bone cyst, chondroblastoma, simple bone cyst, osteoid osteoma, osteoblastoma, osteosarcoma, giant-cell reparative granuloma, Giant-cell tumor of the tendon sheath and brown tumor of hyperparathyroidism. Giant-cell tumor of bone_sentence_26

Treatment Giant-cell tumor of bone_section_4

General treatment regimens have not changed much in the past 30 years, in part due to the lack of randomized clinical trials. Giant-cell tumor of bone_sentence_27

Surgery is the treatment of choice if the tumor is determined to be resectable. Giant-cell tumor of bone_sentence_28

Curettage is a commonly used technique. Giant-cell tumor of bone_sentence_29

The situation is complicated in a patient with a pathological fracture. Giant-cell tumor of bone_sentence_30

It may be best to immobilize the affected limb and wait for the fracture to heal before performing surgery. Giant-cell tumor of bone_sentence_31

Patients with tumors that are not amenable to surgery are treated with radiation therapy. Giant-cell tumor of bone_sentence_32

However caution is employed since a majority of recurrent tumors with transformations to the malignant sarcoma phenotype have been in patients receiving radiotherapy for their primary benign lesion. Giant-cell tumor of bone_sentence_33

Pharmacotherapy for GCTOB, includes bisphosphonates such as Zoledronate, which are thought to induce apoptosis in the MNGC fraction, preventing tumor-induced osteolysis. Giant-cell tumor of bone_sentence_34

Indeed, in vitro studies have shown zoledronate to be effective in killing osteoclast-like cells. Giant-cell tumor of bone_sentence_35

More recently, humanized monoclonal antibodies such as Denosumab targeting the RANK ligand have been employed in treatment of GCTOB in a phase II study. Giant-cell tumor of bone_sentence_36

This is based on the notion that increased expression of RANK-ligands by stromal cells plays a role in tumor pathogenesis. Giant-cell tumor of bone_sentence_37

Epidemiology Giant-cell tumor of bone_section_5

Giant-cell tumor of the bone accounts for 4-5% of primary bone tumors and about 20% of benign bone tumors. Giant-cell tumor of bone_sentence_38

However, significantly higher incidence rates are observed in Asia, where it constitutes about 20% of all primary bone tumors in China. Giant-cell tumor of bone_sentence_39

It is slightly more common in females, has a predilection for the epiphyseal/metaphyseal region of long bones, and generally occurs in the third to fourth decade. Giant-cell tumor of bone_sentence_40

Although classified as a benign tumor, GCTOB has been observed to metastasize to the lungs in up to 5% of cases, and in rare instances (1-3%) can transform to the malignant sarcoma phenotype with equal disease outcome. Giant-cell tumor of bone_sentence_41

See also Giant-cell tumor of bone_section_6

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Credits to the contents of this page go to the authors of the corresponding Wikipedia page: tumor of bone.