Case 31 - Discussion

Uploaded: 2007-03-07, Updated: 2007-06-24

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Karyotype
   
 

Microscopic Description
Multiple sections, including decalcified sections, show a cystic hemorrhagic neoplasm consisting of plump fairly spindle shaped cells interspaced by osteoclast-like giant cells that may contain up to 50 nuclei. The neoplasm is richly vascularized. The slit-like spaces are not lined by a vascular endothelium. Some hemosiderin laden macrophages are present. Occasional areas of osteoid is noted. There are areas of bone destruction and reabsorption, along with areas of new bone growth. The tumor is fairly well circumscribed and does not extend into the surrounding soft tissue. In some areas there is a dense fibroblastic reaction. All margins of resection are free of neoplasm.

ELECTRON MICROSCOPY:
Ultrastructurally, there are sheets of plump fusiform fibroblast-like cells with moderately developed Golgi apparatus and rough endoplasmic reticulum. An occasional lipid droplet is present within these cells. These cells are embedded in a fibrillary matrix. Interspersed are giant cells which contain relatively small nucleoli with marginated chromatin. The cytoplasm of giant cells show abundant mitochondria, multiple Golgi and numerous vesicles. (Interpretation performed by Drs. Hunter and Pan. Performed in the Electron Microscopy Laboratory, Creighton Medical Laboratories, Omaha, NE.)
ULTRASTRUCTURAL IMPRESSION: Giant cell tumor of bone.

CYTOGENETICS REPORT (performed at University of Nebraska Medical Center Human Genetics Laboratory, Omaha, NE, report on file):
Cytogenetic analysis revealed the presence of an abnormal diploid clone characterized by a reciprocal translocation between 6q and 13q and a deletion of 20q. Twelve cells were normal male.
NOMENCLATURE: 46,XY,t(6;13)(q15;q34),del(20)(q13.1)[8]/46,XY[12]

Diagnosis
LEFT MIDDLE FINGER, AMPUTATION:
- Giant cell reparative granuloma of bone, a variant of aneurysm bone cyst.
- Margin of amputation free of tumor.

 

 

 

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