Giant bone cell tumor ( GCTOB ) also called Osteoclastoma _ is a relatively uncommon bone tumor. It is characterized by the presence of multinucleated giant cells (osteoclast-like cells). Malignancies in giant cell tumors are rare and occur in about 2% of all cases. However, if malignant degeneration occurs, it will likely metastasize to the lungs. Giant cell tumors are usually benign, with unpredictable behavior. It is a heterogeneous tumor consisting of three different cell populations. Giant cell tumor stromal cells (GCTSC) are neoplastic cells, derived from osteoblastic origin and are classified by the expression of osteoblast cell markers such as alkaline phosphatase and osteocalcin. In contrast, histiocytic mononuclear cells (MNHC) and multinucleated giant cells (MNGC) were recruited secondary and consisted of non-neoplastic cell populations. They are derived from the osteoclast-monocyte lineage determined primarily by expression CD68 , a marker for monocyte precursor cells. In most patients, the tumor develops slowly, but can recur locally by as much as 50% of cases.
Video Giant-cell tumor of bone
Signs and symptoms
Patients usually come with pain and movement limitations caused by tumor proximity to joint space. Swelling may occur, too, if the tumor has developed for a long time. Some patients may be asymptomatic until they develop pathologic fractures at the site of the tumor. They usually originate from epiphysis of long bones, but in rare cases, they may arise from the anterior bow of the ribs. The symptoms may include muscle pain and pain in the arms or legs and abdominal pain. The patient may also experience nerve pain that feels like an electric shock due to load bearing.
Maps Giant-cell tumor of bone
Diagnosis
The diagnosis of giant cell tumors is based on biopsy findings. The key histomorphological feature is, as the entity name denotes, giant cells (multinucleated) with up to a hundred nuclei that have prominent nucleoli. The small mononuclear cells and the surrounding multinucleates have nuclei similar to giant cells; this distinguishes lesions from other osteogenic lesions that usually have giant osteoclast (benign) gland cells. The soap-bubble appearance is a characteristic feature.
Imaging
In X-rays, giant cell tumors (GCTs) are lytic/lucent lesions that have an epiphyseal location and grow to the articular surface of the involved bone. Radiologically, tumors can show a typical 'soap bubble' appearance. They can be distinguished from other bone tumors in GCT which usually have a nonsclerotic and sharp border. About 5% of giant cell tumors metastasize, usually to the lungs, which may be benign metastases, when the diagnosis of giant cell tumors is suspected, chest X-ray or computed tomography may be necessary. MRI can be used to assess intramedullary extensions and soft tissues.
Treatment
The general treatment regimen has not changed much in the last 30 years, partly due to the lack of randomized clinical trials. Surgery is the treatment of choice if the tumor is determined to be operable. Curettage is a commonly used technique. The situation is complicated in patients with pathologic fractures. Probably best to paralyze the affected limb and wait for the fracture to recover before performing the surgery.
Patients with tumors that are not receiving surgery are treated with radiation therapy. However caution is used because the majority of recurrent tumors with a transformation to the phenotype of malignant sarcoma have been in patients receiving radiotherapy for their primary benign lesions. Pharmacotherapy for GCTOB, including bisphosphonates such as Zoledronate, is thought to induce apoptosis in the MNGC fraction, preventing tumor-induced osteolysis. Indeed, in vitro studies have shown zolidronate to be effective in killing cells such as osteoclasts. More recently, humane monoclonal antibodies such as Denosumab targeting RANK ligands have been used in GCTOB treatment in phase II studies. This is based on the idea that increased RANK-ligand expression by stromal cells plays a role in tumor pathogenesis.
Other bone tumors with giant cells
A number of tumors have giant cells, but not really giant benign cell tumors. These include aneurysm, bone cyst, chondroblastoma, simple bone cyst, osteoid osteoma, osteoblastoma, osteosarcoma, giant cell reparative granuloma, and hyperparathyroidism brown tumor.
Epidemiology
Giant cell tumors in bone account for 4-5% of primary bone tumors and about 20% of benign bone tumors. However, the incidence rate is significantly higher observed in Asia, where it represents about 20% of all primary bone tumors in China. It is slightly more common in women, has a predilection for epiphyseal/metaphyseal regions of long bones, and generally occurs in the third to fourth decade. Although classified as a benign tumor, GCTOB has been observed to metastasize to the lungs in up to 5% of cases, and in rare cases (1-3%) may turn into a malignant sarcoma phenotype with similar disease outcomes.
See also
- Large cell
- Aneurysm bone cyst
References
External links
- "Symposium on Giant Cell Tumors". Indian Journal of Orthopedics . 41 (2). 2007.
- YouTube videos of patients with giant cell tumors removed from the elbow, elbow replacements installed (1 of 6 videos)
- Radiology of Giant Cell Tumors
- GCT Connect - An online network for patients to share experiences
Source of the article : Wikipedia
0 Comments