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Osteosarcoma - conventional

Summary

Osteosarcoma is a tumor comprised of malignant spindle cells that produce osteoid and bone, that occurs most commonly in the long bones of teenagers and young adults.

The peak age of incidence is around 18 or 20. Males are more commonly affected than females. About 600 children are affected each year in the United States. Individuals of all ages can be affected. Older persons are at increased risk for certain types of secondary oseosarcoma tumors, such as post radiation osteosarcoma and post-Paget's osteosarcoma.
The most common presentation is pain and a mass, which occurs near a joint.
On radiographs, conventional osteosarcoma occurs predominately in the metaphysis, and appears as a mixed sclerotic and lytic lesion, that may permeate the bone and the nearby cortex, causing a soft tissue mass and a periosteal reaction.
Before treatment can be planned, a complete oncological staging workup must be completed. For most types of osteosarcoma, treatment is multi-modal, including chemotherapy and surgery.
Complete Information on this Tumor
Introduction and Definition: 

Osteosarcoma (osteogenic sarcoma) is the most common primary sarcoma of bone. In its most common form it is an aggressive sarcoma that occurs in the teenagers and young adults, a little bit more commonly you nails and then in females. However it can occur at any age. The most common sites is the distal femur and proximal tibia. Approximately 1000 new cases of osteosarcoma occur in the United States each year, including about 600 in children.

Incidence and Demographics: 
Osteosarcoma is not caused by injury or trauma, by fluoride in water, or by exposure to chemicals. The exact cause is unknown. In most cases, an abnormality in the chromosomal DNA (the genes) of a primitive bone cell or bone precursor cell can be detected. This abnormality may be the loss of a tumor suppressor gene, or DNA helicase genes, which causes the cell to grow abnormally and in an uncontrolled fashion. About 85% of osteosarcoma cases are of the "conventional intramedullary" type, and the other 15% consists of several other subtypes, including telangectatic, low-grade intramedullary, and small cell, as well as the surface subtypes parosteal, periosteal, and high-grade surface osteosarcoma. Please click on the subtype to learn more about that particular tumor. In the last two decades, a more complete understanding of the molecular basis of osteosarcoma has emerged. Certain sarcomas, such as Ewing sarcoma and synovial sarcoma contained specific DNA translocations that may have a role in the origin of these tumors. Other sarcomas containing frequent nonspecific DNA alterations with very numerous gains and losses of DNA material between chromosomes. Rapid developments are occurring the field of sarcoma molecular testing and genetic testing, but further studies are necessary. Osteosarcoma has many subtypes, each subtype has its own page of this website. The subtype are: Conventional osteosarcoma (conventional intramedullary osteosarcoma) periosteal osteosarcoma parosteal osteosarcoma telangectatic osteosarcoma post-paget osteosarcoma post radiation osteosarcoma high-grade surface osteosarcoma Multifocal osteosarcoma Small cell osteosarcoma
Symptoms and Presentation: 

The most common presentation is pain and a mass, which occurs near a joint. The pain may initially accompany activity, at gradually becomes more constant and may be severe at night. Patient otherwise may have few were no symptom.

X-Ray Appearance and Advanced Imaging Findings: 
The most common form of osteogenic sarcoma is conventional osteosarcoma, which accounts for 75 to 85% of all osteosarcoma. On radiographs, conventional osteosarcoma occurs predominately in the metaphysis, and appears as a mixed sclerotic and lytic lesion, that may permeate the bone and the nearby cortex, causing a soft tissue mass and a periosteal reaction. Bone formation within the tumor is characteristic of osteosarcoma and is usually visible on the x-rays.
Laboratory Findings: 
Laboratory tests do not aid in the diagnosis, but a link between alkaline phospatase levels in the blood and prognosis of the disease has been established.
Preferred Biopsy Technique for this Tumor: 
Biopsy must be carefully planned so that subsequent definitive surgical removal of the tumor is not compromised. Most authors strongly recommend that the biopsy be performed by the surgeon who will be doing the final tumor resection. An increased rate of avoidable amputations has been attributed to errors in biopsy technique.
Histopathology findings: 
The differential diagnosis should always include infection, other possibilities include lymphoma, chondrosarcoma, sarcomas such as Ewing's and MFH.
Treatment Options for this Tumor: 
Before treatment can be planned, a complete oncological staging workup must be completed. This includes assessment of any potential for metastasis to the chest, to nearby bones or the rest of the extremity, or to other areas as indicated. Most patients have computed tomography scans of the chest, whole-body bone scan, and MRI of the extremity including the lesion. Additional scans such as positron admission tomography (PET) scan may have a role in the staging workup. For most types of osteosarcoma, treatment is multi-modal. Generally neoadjuvant chemotherapy is given prior to surgery. Surgical resection with a wide margin, achieving the widest possible margin without unnecessary functional sacrifice is then carried out. The vast majority of patients do not require amputation but rather can be treated with limb sparing surgery, also called limb salvage surgery. The tumor is removed and the excised segment of bone is replaced with a prosthesis, and allograft bone, or a combination of these. Other techniques also exist. Following surgery, postoperative chemotherapy is usually given, and may be modified depending on the response of the tumor to the preoperative chemotherapy. Radiation is usually not used.
Preferred Margin for this Tumor: 
wide
Outcomes of Treatment and Prognosis: 
The treatment and prognosis of osteogenic sarcoma depend very largely on the extent of the tumor. Localized, non-metastatic tumors in relatively accessible sites such as the knee, hip, and shoulder generally has a very good to excellent prognosis. Very large tumors and tumors in difficult sites such as the pelvis and spine have a less favorable prognosis due to the difficulty with completely removing the tumor by surgical techniques. Once clinically evident metastasis occurs, the prognosis is substantially diminished. Tumors that present with metastasis already present or tumors where metastasis is discovered after the initial treatment have a poor prognosis. Surgical removal of metastasis coupled with chemotherapy may lead to improved survival.
Special and Unusual Features: 
It is estimated that that 80% of patients with osteosarcoma have metastasis at presentation, although only 15% of these mets are clinically apparent. The most common site of metastasis is the lungs. This is why systemic chemotherapy is prescribed for all patients. As a result, a certain number of patients who do not need to get chemotherapy still must receive the potentially harmful treatments. Current research is aimed at determining which patients do not have metastasis so that they might avoid the need for chemotherapy. Following treatment of osteosarcoma, patients continue to experience lingering effects. The functional capacity may be slightly too seriously impaired depending on the extent of the tumor and the success of the limb sparing surgery. Lingering effects and toxic effects of the chemotherapy require ongoing observation and sometimes treatment. Most patients experience some amount of diminution of their quality of life. In summary, osteogenic sarcoma is an aggressive and potentially fatal cancer that affects all ages, but his most common in the long bones of teenagers and young adults. Current treatment results in excellent chances for survival for patients with manageable tumors who do not have metastasis. Although patient experienced lingering effects following treatment, these are readily accepted due to the aggressive and potentially deadly nature of the tumor.
Suggested Reading and Reference: 
A large number of health-related internet sites have information on this topic. The National Library of Medicine has a very comprehensive on-line database (entrez-pubmed) that provides free access to a large number of resources on this tumor.