Osteosarcoma is a primary malignancy of bone. The malignant cells produce osteoid. Osteosarcoma Histologically the tumor is composed of malignant osteoblasts which produce osteoid Most occur in the metaphysis of long bones especially about he knee. Age - 10 to 20 years. If seen later in life consider a secondary malignancy ( to Paget's or post irradiation) It metastases to the lungs and to other bones.


Poor in South Africa (20% 5 yr. survival, because of late presentation). International experience is towards a 60% survival.

Histology of an osteosarcoma. Note the malignant osteoid (pink trabeculae)
Osteosarcoma X-ray Features
X-ray features
Codman's triangle, Sunray spicules


Ewing's Sarcoma

Ewing's is a small cell tumor seen in the 10 to 25 yr. age group. 60% occur in the long bones, but the scapula and pelvis are often affected.
Ewings - onion skin
The tumor lifts the periosteum to produce the typical onion skin appearance
Ewings - small cell tumor
Small cells of uniform size. On electron microscopy the cells contain glycogen granules

Ewing's is one of the few tumors that frequently originate in the shaft of long bones. 50% originate in the diaphysis. It is an osteolytic tumor and has a large soft tissue component. It may mimic chronic osteomyelitis and even produce a raised body temperature and ESR as well as white cell count. Histologically the tumor consists of monotonous sheets of small round cells. Ewings Sarcoma of the proximal humerus
Poor 30% have lung or bony metastases at time of presentation.








Myeloma is a common primary tumour from the 5th decade onwards. Myeloma presents with lytic bone lesions which commonly lead to pathological fracture. Myeloma
Common in any bone containing red marrow especially flat bones eg pelvis as well as vertebra. Consider the diagnosis in a vertebral fracture in the elderly. Typically the vertebra is flattened the so called "wafer" vertebra. If there is systemic involvement the skull x-ray may show "punched out" lytic lesions.
Affects bone containing red marrow (skull, ribs, vertebrae, sternum, pelvis)
Weakness, bone pain and pathological fractures
Backache is common and may cause root pain and occasionally paraplegia
Anemia, generalised malaise and cachexia

    Effects of Myeloma

  • Local bone destruction by the tumour
  • High plasma protein concentration
  • Renal effects of abnormal plasma proteins
      • Renal Failure
      • Gout
    Diagnosis Myeloma
  • ESR usually >100 mm/hr
  • Serum Electrophoresis
  • Urine Bence Jones Protein
  • Serum immunoelectrophoresis
  • Bone marrow biopsy
  • Biopsy - only occasionally needed


The tumor is composed of abnormal plasma cells. If the tumor is localised to one bone it is known as a plasmacytoma Systemic involvement is known as multiple myeloma A bone marrow biopsy must be done from the pelvic rim to determine the extent of spread.

Myeloma Histology
Histology Myeloma
Consists of plasma cells
Serum electrophoresis
Monoclonal peaks are seen in multiple myeloma. Peaks such as the one on the right do not correspond to the usual Alpha and Beta peaks



Chondrosarcoma usually presents after 6th decade. Characteristically chondrosarcoma is slow growing and seen proximally in the skeleton e.g. prox. humerus and pelvis.

Chondrosarcoma distribution and age incidence

Chondrosarcoma arising from an Osteochondroma.
The patient has multiple enchondromas. The lesion on the left ilium has developed an indistinct border. Compare this to the enchondromas on the proximal femurs.

Click on the image for other views.

Chondrosarcoma of proximal humerus
    Chondrosarcoma often arises secondary to other tumours.




    Secondary Chondrosarcoma

  • Osteochondromata esp. Multiple
  • Enchondroma esp. Ollier's (25%)
  • Mafucci (100%)
  • Chondroblastoma
  • Chondromyxiod fibroma
  • Synovial chondromatosis



Surgery alone is the only hope of cure with this tumour. Chondrosarcoma is unresponsive to irradiation and chemotherapy. Block excision is recommended.

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