Osteosarcoma overview: Difference between revisions
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Revision as of 15:41, 29 September 2015
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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Osteosarcoma Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Osteosarcoma overview On the Web |
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American Roentgen Ray Society Images of Osteosarcoma overview |
Overview
Bone cancer is a malignant (cancerous) tumor of the bone that destroys normal bone tissue (1). Not all bone tumors are malignant. In fact, benign (noncancerous) bone tumors are more common than malignant ones. Both malignant and benign bone tumors may grow and compress healthy bone tissue, but benign tumors do not spread, do not destroy bone tissue, and are rarely a threat to life.
Malignant tumors that begin in bone tissue are called primary bone cancer. Cancer that metastasizes (spreads) to the bones from other parts of the body, such as the breast, lung, or prostate, is called metastatic cancer, and is named for the organ or tissue in which it began. Primary bone cancer is far less common than cancer that spreads to the bones.
There are three types of bone cancer:
- Osteosarcoma - develops in growing bones, usually between ages 10 and 25
- Chondrosarcoma - starts in cartilage, usually after age 50
- Ewing's sarcoma - begins in nerve tissue in bone marrow of young people, often after treatment of another condition with radiation or chemotherapy
Osteosarcoma is the most common type of malignant bone cancer, accounting for 35% of primary bone malignancies. There is a preference for the metaphyseal region of tubular long bones. 50% of cases occur around the knee. It is a malignant connective (soft) tissue tumor whose neoplastic cells present osteoblastic differentiation and form tumoral bone.
Classification
Osteosarcomas may be classified into several subtypes based on differentiation, location within the bone, and histological variants.
Pathophysiology
The osteosarcomas may be localized at the end of the long bones (commonly in the metaphysis). Most often it affects the upper end of tibia or humerus, or lower end of femur. On gross pathology, areas of bone formation, hemorrhage, fibrosis, and cystic degeneration on cut surface are characteristic findings of osteosarcoma. On microscopic histopathological analysis, presence of osteoid within the tumor, pleomorphic cells, anaplastic cells, and atypical mitoses are characteristic findings of osteosarcoma.
Causes
There are no established causes for osteosarcoma.
Differential Diagnosis
Osteosarcoma must be differentiated from Ewing's sarcoma, Giant cell tumors, Malignant fibrous histiocytoma, Osteomyelitis, and aneurysmal bone cyst.
Epidemiology and Demographics
Risk Factors
The common risk factors in the development of osteosarcoma are radiation to bones, alkylating antineoplastic agents, paget disease, Multiple hereditary osteochondromas, Fibrous dysplasia, Bloom syndrome,Rothmund-Thomson syndrome, and Li-Fraumeni syndrome.
Screening
Screening for osteosarcoma is not recommended.
Natural History, Complications and Prognosis
Common complications of osteosarcoma include pathologic fracture and metastasis. The 5-year survival rate of osteosarcoma after adequate therapy is approximately 60-80%. Pretreatment factors that influence outcome of the osteosarcoma are primary tumor site, size of the primary tumor, and site of metastasis.
Diagnosis
Staging
According to the American Joint Committee on Cancer (AJCC), there are four stages of osteosarcoma based on the size of primary tumor, metastasis, involvement of lymph nodes, and grade of the tumor.
History and Symptoms
The most common symptoms of osteosarcoma include bone pain that may be worse at night, swelling, and redness at the site of the tumor. The affected bone is not as strong as normal bones and may fracture with minor trauma (a pathological fracture).
Physical Examination
Physical examination findings will depend on the location of the osteosarcoma. Common physical examination findings of osteosarcoma are localized swelling and tenderness.
Laboratory Findings
Laboratory tests for osteosarcoma include complete blood count (CBC), blood chemistry studies such as serum alkaline phosphatase and lactate dehydrogenase.
Biopsy
Biopsy of osteosarcoma is important for confirming the diagnosis and for determining histologic subtype.[1] Biopsy may be performed percutaneously with fine- or wide-bore needles, or through a formal incision.
X Ray
On x-ray, osteosarcoma is characterized by medullary and cortical bone destruction, periosteal reaction, tumor matrix calcification and soft tissue mass.[2]
CT
The role of CT scan in osteosarcoma is predominantly in assisting biopsy and staging, but adds little to plain radiography and MRI in direct assessment of the tumor.[3]
MRI
On MRI, osteosarcoma is characterized by intermediate intensity of soft tissue and low signal intensity of ossified components on T1. High signal intensity of soft tissue and low signal imtensity of ossified components on T2. Considerable contrast enhancement of solid components on T1 contrast.
Other Imaging Findings
Bone scan in osteosarcoma is used to observe abnormal areas of bone and metastasis.[4]
Other Diagnostic Studies
No additional tests are recommended for the diagnosis of melanoma.
References
- ↑ Osteosarcoma. surgwiki. http://www.surgwiki.com/wiki/Diseases_of_bone_and_joints#SURGERY_4
- ↑ Osteosarcoma. Dr Amir Rezaee ◉ and Dr Frank Gaillard ◉ et al. Radiopaedia.org 2015. http://radiopaedia.org/articles/osteosarcoma
- ↑ Osteosarcoma. Dr Amir Rezaee ◉ and Dr Frank Gaillard ◉ et al. http://radiopaedia.org/articles/osteosarcoma
- ↑ Osteosarcoma. Canadian Cancer Society. http://www.cancer.ca/en/cancer-information/cancer-type/bone/diagnosis/?region=bc