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Osteoclastoma

Updated : April 17, 2024





Background

The giant cell tumor of bone, also referred to as osteoclastoma or myeloid sarcoma, is a benign osteolytic neoplasm that typically affects young adults. These tend to originate in the metaphysis of long bones and expand into the epiphysis.

While the majority of GCTB are benign, they rarely spread to the lungs. Their behavior is clinically unpredictable. A histological examination is required for diagnosis confirmation. Plain film and CT imaging of the main location is the suggested method for diagnosing this condition.

A chest CT or chest X-ray is also indicated for the evaluation of lung metastases. Typically, curettage or extensive resection is utilized, and the prognosis is favorable. GCTB undergoes rare malignant transformations.

They might be either primary or secondary. Primary GCTB frequently occurs adjacent to benign GCTB, whereas secondary GCTB typically develops near the treatment site. The prognosis for malignant GCTB is bleak.

Epidemiology

GCTB is a relatively uncommon neoplasm, comprising only around 3%-5% of all primary bone malignancies. It often affects young individuals, especially in the 3rd and 4th decades of their life and is slightly more prevalent in women.

In individuals with Paget disease, which often affects the pelvic or cranial bones, there is an increase in incidence, although the risk factors are not entirely recognized.

The aberrant laboratory values of these patients will present as high alkaline phosphate levels. In the absence of Paget’s disease, GCTB typically manifests as a single lesion affecting the following bones in this order of incidence:

  • Distal femur and proximal tibia: 50%-65% of cases
  • The distal radius
  • The sacrum
  • The vertebral body

While solitary GCTBs account for the bulk of occurrences, multicentric GCTBs have also been described by researchers (less than 1 percent).

Typically, these are adolescents before epiphyseal closure. If a multicentric GCTB is suspected, it is prudent to consider a radionuclide bone scan for additional examination.

Anatomy

Pathophysiology

The pathophysiology of GCTB is not fully known, although it is believed that a possible cause might be due to osteoblast-like mononuclear stromal cells overexpressing the RANK/RANKL signaling pathway.

This overexpression causes monocytic pre-osteoclast cells to develop into osteoclast cells. These tumors exhibit osteolysis as a result of the osteolysis caused by these osteoclasts.

Etiology

The ethology of GCTB is not clearly defined or understood. However, it is believed that the mononuclear cells arise from primitive mesenchymal cells. These cells express RANKL and exhibit osteoblastic progenitor characteristics.

Genetics

Prognostic Factors

The prognosis for a giant cell bone tumor is favorable, albeit local recurrence can vary. This is mostly influenced by the degree of the resection (extensive local excision has the lowest rate of recurrence but the highest morbidity) and whether an adjuvant was used in addition to surgery.

A GCTB situated close to the spinal cord has a worse prognosis and a high local recurrence rate.  According to studies, the recurrence rate for intralesional curettage without a local adjuvant can reach up to 50% in two years. In an effort to lower recurrence rates, local adjuvants are suggested in addition to surgery.

Retrospective studies have showed a 13%-23% reduction in recurrence rates, however randomized trials are needed to support this conclusion. In addition, there is interest in utilizing the drug denosumab as an adjuvant after surgery, although more research is required.  Rarely, GCTB undergoes a malignant change, which is frequently associated with a poorer prognosis.

The optimal frequency of posttreatment monitoring varies. However, the primary site is routinely examined with a CT 3 months after treatment, then 2 times a year for 2 years, and once a year for the following 5 years. The frequency and length of treatment should be determined on a case-to-case basis.

Clinical History

Physical Examination

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Medication

Media Gallary

References

https://www.ncbi.nlm.nih.gov/books/NBK551681/

https://pubmed.ncbi.nlm.nih.gov/16180228/

Osteoclastoma

Updated : April 17, 2024




The giant cell tumor of bone, also referred to as osteoclastoma or myeloid sarcoma, is a benign osteolytic neoplasm that typically affects young adults. These tend to originate in the metaphysis of long bones and expand into the epiphysis.

While the majority of GCTB are benign, they rarely spread to the lungs. Their behavior is clinically unpredictable. A histological examination is required for diagnosis confirmation. Plain film and CT imaging of the main location is the suggested method for diagnosing this condition.

A chest CT or chest X-ray is also indicated for the evaluation of lung metastases. Typically, curettage or extensive resection is utilized, and the prognosis is favorable. GCTB undergoes rare malignant transformations.

They might be either primary or secondary. Primary GCTB frequently occurs adjacent to benign GCTB, whereas secondary GCTB typically develops near the treatment site. The prognosis for malignant GCTB is bleak.

GCTB is a relatively uncommon neoplasm, comprising only around 3%-5% of all primary bone malignancies. It often affects young individuals, especially in the 3rd and 4th decades of their life and is slightly more prevalent in women.

In individuals with Paget disease, which often affects the pelvic or cranial bones, there is an increase in incidence, although the risk factors are not entirely recognized.

The aberrant laboratory values of these patients will present as high alkaline phosphate levels. In the absence of Paget’s disease, GCTB typically manifests as a single lesion affecting the following bones in this order of incidence:

  • Distal femur and proximal tibia: 50%-65% of cases
  • The distal radius
  • The sacrum
  • The vertebral body

While solitary GCTBs account for the bulk of occurrences, multicentric GCTBs have also been described by researchers (less than 1 percent).

Typically, these are adolescents before epiphyseal closure. If a multicentric GCTB is suspected, it is prudent to consider a radionuclide bone scan for additional examination.

The pathophysiology of GCTB is not fully known, although it is believed that a possible cause might be due to osteoblast-like mononuclear stromal cells overexpressing the RANK/RANKL signaling pathway.

This overexpression causes monocytic pre-osteoclast cells to develop into osteoclast cells. These tumors exhibit osteolysis as a result of the osteolysis caused by these osteoclasts.

The ethology of GCTB is not clearly defined or understood. However, it is believed that the mononuclear cells arise from primitive mesenchymal cells. These cells express RANKL and exhibit osteoblastic progenitor characteristics.

The prognosis for a giant cell bone tumor is favorable, albeit local recurrence can vary. This is mostly influenced by the degree of the resection (extensive local excision has the lowest rate of recurrence but the highest morbidity) and whether an adjuvant was used in addition to surgery.

A GCTB situated close to the spinal cord has a worse prognosis and a high local recurrence rate.  According to studies, the recurrence rate for intralesional curettage without a local adjuvant can reach up to 50% in two years. In an effort to lower recurrence rates, local adjuvants are suggested in addition to surgery.

Retrospective studies have showed a 13%-23% reduction in recurrence rates, however randomized trials are needed to support this conclusion. In addition, there is interest in utilizing the drug denosumab as an adjuvant after surgery, although more research is required.  Rarely, GCTB undergoes a malignant change, which is frequently associated with a poorer prognosis.

The optimal frequency of posttreatment monitoring varies. However, the primary site is routinely examined with a CT 3 months after treatment, then 2 times a year for 2 years, and once a year for the following 5 years. The frequency and length of treatment should be determined on a case-to-case basis.

https://www.ncbi.nlm.nih.gov/books/NBK551681/

https://pubmed.ncbi.nlm.nih.gov/16180228/