Giant Cell Tumor is the commonest benign tumor that is encountered by an orthopedic surgeon which consists of 5% of all skeletal tumors and 20% of all skeletal neoplasms.
The peak incidence of this tumor occurs in skeletally mature individuals in 3rd decades of their lives.
Female: Male= 1.5:1
GCT is seen in epiphysis after epiphyseal closure.
Clinical Features of GCT
Pain presents with variable severity
Mass is present
5 – 10 % of individuals present with pathological fractures
A common location is a Knee > Distal radius
Radiological Features of GCT
Lytic lesion centered in epiphysis involving metaphysis involving at least or a part of subchondral bone.
Bulging of tumor beyond the cortex is seen
The tumor has mostly well-defined margins, sometimes ill-defined, and seldom a thin shell of reactive bone.
No mineralized tumor matrix is found
Characterized lobulated: Soap Bubble appearances are seen
Sometimes free fluid level is seen which is secondary to ABC.
MRI shows Doughnut Sign
Campanacci Grading based on Radiological Appearances
| Grade | Features |
|---|---|
| Grade I | Well-defined border of the thin rim of mature bone and the cortex was intact or slightly thinned out |
| Grade II | Relatively well marginated but no radioopaque rim; the combined cortex and rim of reactive bone was rather thin and moderately expanded but still present. |
| Grade III | Fuzzy borders, suggesting rapid and possible [ermeative growth; tumor bulged into soft tissue but soft tissue mass did not follow the contour of bone and was not limited by the apparent shell of reactive bone. |
Pathology
Epiphysis in location, eccentrically placed
Surrounded by a thin rim of reactive bone
Reddish brown to yellow
Microscopic Examination:
- Round to polygonal mononuclear cells and multinucleated osteoclast-like giant cells (> 50 nuclei)
- Uniformly scattered
- Storiform arrangement of fibroblast
Treatment of Giant Cell Tumor
Function preserving surgery:- Intralesional curettage with appropriate reconstruction
Expandable bones like the lower end of the ulna/ upper end of the fibula excision of the lesion are advocated.
Role of Chemotherapy and Radiotherapy
Radiation therapy is done in unresectable lesions, especially in the spine
Role of embolization and bisphosphonates
In Unresectable GCT (Near spinal cord, sacral, and pelvis tumors)
Recurrence rate: High as 30-50% mostly in the first 2 years.
Pulmonary metastasis is seen in 1 % to 6 %.
Local recurrence with repeated surgical intervention seems to be associated with lung metastasis.
Malignant transformation is unusual but reported. Post-reduction sarcoma can develop.
Denosumab:
Denosumab is used in inoperable tumors
If the joint cannot be saved go for the resection, denosumab will help in thickening the wall for graft.
Still, there is a high chance of recurrence.
See also: Osteoblastoma
See also: Osteoid Osteoma
See also: CHONDROBLASTOMA
