Case 43 - Discussion

Uploaded: 2007-05-05, Updated: 2007-06-22
EM EM
EM EM
EM EM
   
  ELECTRON MICROSCOPY
Ultrastructurally, tumor consists of irregular large multinucleated cells with abundant cytoplasm. The cytoplasm is filled with a large number of mitochondria and small vacuoles. The nuclei are irregular with one centrally localized nucleolus, but small in relationship to the cytoplasm. Abundant vessels are present. No osteoid is noted.

CYTOGENETICS REPORT
Normal male chromosome complement.
Cytogenetic analysis did not reveal any evidence of a consistent detectable numerical or structural chromosomal anomaly at this band level.
NOMENCLATURE: 46,XY[19]
 

Giant Cell Tumor

Clinical Futures
 

  • 5% of primary bone tumor and 20% of benign bone tumor;

  • Age: 30-40, slightly F>M;

  • Sites: the ends (epiphyses) of long bones. Most common sites, distal femur > proximal tibia (totally 46%) >distal end of radius;

  • Most common symptom, pain. Rare pathologic fracture;

Radiology Findings
 

  • Eccentric, well-demarcated, purely lytic lesion in the end of long bone;

  • >50% involve the articular cartilage;

  • Soft tissue extension and formation of eggshell new bone;

  • Not often sclerosis.

Gross Findings
 

  • Eccentric at the end of long bone;

  • Large or small cystic areas. Thinned cortex, extension to the soft tissue with eggshell new bone;

  • Soft tumor, typically dark brown, may have yellow discoloration.

Microscopic Findings
 

  • Mononuclear cells and giant cells, typically arranged in a compact fashion, no collagen formation;

  • Mononuclear cells: round/oval nuclei with uniformly distributed chromatin and indistinct nucleoli; mitosis always present, but never atypical;  amphophilic to eosinophilic cytoplasm with indistinct borders, may appear vacuolated;

  • Giant cells: multinucleated, 40-60; nuclear features similar to mononuclear cells;

  • Mononuclear cells may be spindle and arranged in a storiform pattern;

  • frequent clusters of foam cells;

  • Secondary aneurysmal bone cyst, not uncommon;

  • Reactive bone formation;

  • Areas of infarct-like necrosis, common.

Differential Diagnosis
 

  • Aneurysmal bone cyst: skeletally immature patients; predominantly metaphyseal; spindled mononuclear cells; produce collagen;

  • Metaphyseal fibrous defect

  • Chondroblast

  • Osteosarcoma with giant cells

Immunohistochemistry Straining
 

  • Over expression of c-myc, strong association with metastasis;

  • u-PA, u-PAR, PAI-1, higher aggressiveness.

Election Microscopy
   

Cytogenetics
 

  • Telomeric association, 19q>11p>15p>21p>20q>1p

Treatment and Prognosis
 

  • Curettage

  • Recurrence, 25-50%

  • Rarely metastasis, <3%

Reference
 

  • AFIP, series 4