Malignant Tumors of Bone Flashcards
What is the most common primary malignant bone tumor?
Osteosarcoma
What mutations are associated with osteosarcomas?
Tumor suppressor genes (Rb, p53)
Where is the general site of osteosarcomas?
Arise near the knee, in the lower femur and upper tibia/fibula
What is the radiologic finding associated with osteosarcoma?
Codman triangle (Shell of bone intersecting the cortex at one end and open at theother end)
Where does osteosarcoma metastasize?
To the lungs
What do the malignant cells in osteosarcoma stain for?
Alkaline phosphatase and osteonectin
What is the name of maligant tumor of cartilage?
Chondrosarcoma
What transcription factor is expressed in chondrosarcoma?
SOX9
What are the three anatomic variants of chondrosarcoma?
- Central
- Peripheral
- Juxtacortical
From where does central chondrosarcoma arise?
The medullary cavity of pelvic bones, ribs, and long bones
From where does peripheral condrosarcoma arise?
Arises outside the bone, almost always in the cartilaginous cap of an osteochondroma
From where do juxtacortical chondrosarcomas arise?
Metaphyses of long bones lying on the outer surface of the cortex
What genetic defect is associated chondrosarcoma?
Trisomy 7
To where do giant cell tumors typically metastasize?
They rarely metastasize
What is a giant cell tumor?
Benign locally aggressive neoplasm
What are giant cell tumors microscopically characterized by?
Mononuclear “stromal” cells and large osteoclastic giant cells
What is the neoplastic component of the GCT?
The mononuclear cells
What is Ewing Sarcoma?
Primitive Neuroectodermal tumor of childhood
What is the genetic alteration that occurs in Ewing Sarcoma?
11 22 translocation resulting in the fusion of the famino terminus of the EWS1 gene to the carboy terminus of the FLI-1 gene which encodes a transcription factor
What is the radiologic findings of Ewing Sarcoma on xray?
Onion-skin pattern of periosteal bone
How does EWS appear on microscopic exam?
Cells are closely packed, small, round cells with little cytoplasm. Fibrous strands separate sheets of cells. Rosettes can be found.
What characteristic marker can be stained for in EWS?
CD99
What lesions are caused by multiple myeloma?
Lytic lesions in bone
What causes the lytic lesions found on bone in mutliple myeloma?
Myeloma cells secrete cytokines that activate osteoclasts
What are the most malignant tumors in bones?
Metastatic tumors
What is the most common site of bone metastases in adults? In children?
- Adult - spine
- Children - appendicular skeleton
