Introduction
Radiograph of the femur in a patient with osteosarcoma shows a typical Codman triangle (arrow) and more diffuse, mineralized osteoid within the soft tissues adjacent to the bone.
Lateral isotope bone scan (see also Image 9 in the Multimedia Section) reveals intense uptake in the calcaneal region. The remainder of the skeleton appeared normal.
Background
Osteosarcoma is the most common primary malignant tumor of bone, excluding plasma cell myeloma. Classic, or conventional, osteosarcoma represents the most common variant of osteosarcoma, accounting for approximately 75% of all lesions. Osteosarcoma may affect any bone; it is treated by a combination of surgical excision and chemotherapy.1,2,3,4
Related eMedicine topics:
Osteosarcoma (Orthopedic Surgery)
Osteosarcoma, Variants
Related Medscape topics:
Specialty Site Radiology
Specialty Site Hematology-Oncology
Radiology CME and News
Pathophysiology
Osteosarcoma is a malignant mesenchymal sarcoma characterized by the direct formation of bone or osteoid by tumor cells. Osteosarcoma is subclassified on the basis of the histologic characteristics of the cells. When the majority of the cells produce osteoid, the tumor is called osteoblastic. When production of chondroid matrix is predominant, the tumor is classified as a chondroblastic osteosarcoma. When spindle cells are in the majority and little matrix is formed, the term fibroblastic osteosarcoma is used.
Frequency
United States
The incidence of classic osteosarcoma in persons younger than 20 years is 4.8 cases per million population. The incidence of osteosarcoma peaks in persons aged 10-20 years; this period corresponds to the period of maximal skeletal growth. A second, smaller peak in the distribution of osteosarcoma as a whole is seen in late adulthood; this reflects the occurrence of secondary osteosarcoma, which is usually related to Paget disease.
Mortality/Morbidity
The overall prognosis of patients with classic osteosarcoma depends on the stage of the tumor at presentation. The overall 5-year survival rate for patients whose disease was diagnosed between 1974 and 1994 was 63% (59% for males, 70% for females).
Race
Osteosarcoma occurs in all racial and ethnic groups, but the incidence is slightly higher in African Americans than in whites.
Sex
Conventional osteosarcoma is slightly more common in males — the male-to-female ratio is 3:2. This difference is thought to be related to the longer period of skeletal growth in males.
Age
Conventional osteosarcoma has a bimodal distribution. It occurs most frequently in persons 10-20 years of age; this period coincides with the time of maximal skeletal growth. Most cases occur in patients younger than 40 years, but a second small peak is seen in those older than 60 years. Osteosarcoma is rare in young children.
Anatomy
Conventional osteosarcoma occurs most commonly in the metaphyses of long tubular bones, particularly around the knee joint (distal femur, proximal tibia), where skeletal growth rates are high. The proximal humeral metaphysis is another common site. The disease commonly extends from the metaphysis into the adjacent diaphysis or epiphysis. In young patients with unfused physes, the tumor may infiltrate or cross the growth plate, although this does offer some resistance, and the lesion often appears to be demarcated by the physis. Intra-articular extension is uncommon. Remote additional foci of tumor within the same bone (ie, skip lesions) may occur, though they are rare. To exclude these skip lesions, it is important to image the entire length of the bone with MRI.
Presentation
The presentation of patients with classic osteosarcoma typically includes pain and swelling. Patients often present when soft tissue extension has already occurred. Symptoms may have been present for weeks or months. Movement may be restricted, or local changes of inflammation or venous stasis may be present. A small proportion of patients present with a pathologic fracture through the tumor — a feature that is associated with a worse prognosis.5
Preferred Examination
For patients with classic osteosarcoma, radiography is almost always the initial imaging modality. Once the diagnosis is suspected, MRI is essential to determine the distribution of the tumor within the bone and the extent of any associated soft tissue mass. CT is less sensitive than MRI in local evaluation of the tumor, but it is used in the staging of pulmonary metastases.6,7
Histologic confirmation of the nature of the tumor is required initially and should be performed only after baseline MRI studies are made. Biopsy should always be planned in consultation with the patient's orthopedic surgeon to ensure that compartments to be preserved are not contaminated by the needle track (see Osteosarcoma). Bone tumors that are densely sclerotic may not be amenable to percutaneous biopsy. However, the associated soft tissue component may be accessible to ultrasonography-guided biopsy.
Differential Diagnoses
Chondrosarcoma
Ewing Sarcoma
Giant Cell Tumor
Osteosarcoma, Variants
Stress Fracture
Other Problems to Be Considered
Primitive neuroectodermal tumors
Osteomyelitis
Langerhans cell histiocytosis
Rhabdomyosarcoma
Fibrosarcoma
Benign chondroid tumors
Benign osseous tumors
More on Osteosarcoma, Classic |
 Overview: Osteosarcoma, Classic |
| Imaging: Osteosarcoma, Classic |
| Follow-up: Osteosarcoma, Classic |
| Multimedia: Osteosarcoma, Classic |
| References |
| Further Reading |
| Next Page » |
References
Unni KK. Osteosarcoma. In: Unni KK, ed. Dahlin's Bone Tumors: General Aspects and Data on 11,087 Cases. 5th ed. Philadelphia:. Lippincott-Raven;1996: 143-84.
White LM, Kandel R. Osteoid-producing tumors of bone. Semin Musculoskelet Radiol. 2000;4(1):25-43. [Medline].
Picci P. Osteosarcoma (osteogenic sarcoma). Orphanet J Rare Dis. Jan 23 2007;2:6. [Medline].
Emanuel PO, Idrees MT, Leytin A, Kwon EJ, Phelps RG. Aggressive osteogenic desmoplastic melanoma: a case report. J Cutan Pathol. May 2007;34(5):423-6. [Medline].
Glasser DB, Lane JM, Huvos AG, et al. Survival, prognosis, and therapeutic response in osteogenic sarcoma. The Memorial Hospital experience. Cancer. Feb 1 1992;69(3):698-708. [Medline].
Resnik D, Kyriakos M, Greenaway GD. Tumors and tumor-like lesions of bone: imaging and pathology of specific lesions. In: Diagnosis of Bone and Joint Disorders. 4th ed. Philadelphia: WB Saunders Co;2002: 3800-15.
Sorenson BS, Banton KL, Frykman NL, Leonard AS, Saltzman DA. Attenuated Salmonella typhimurium with interleukin 2 gene prevents the establishment of pulmonary metastases in a model of osteosarcoma. J Pediatr Surg. Jun 2008;43(6):1153-8. [Medline].
Gronemeyer SA, Kauffman WM, Rocha MS. Fat-saturated contrast-enhanced T1-weighted MRI in evaluation of osteosarcoma and Ewing sarcoma. J Magn Reson Imaging. May-Jun 1997;7(3):585-9. [Medline].
Hoffer FA, Nikanorov AY, Reddick WE. Accuracy of MR imaging for detecting epiphyseal extension of osteosarcoma. Pediatr Radiol. May 2000;30(5):289-98. [Medline].
Iwasawa T, Tanaka Y, Aida N. Microscopic intraosseous extension of osteosarcoma: assessment on dynamic contrast-enhanced MRI. Skeletal Radiol. Apr 1997;26(4):214-21. [Medline].
Lang P, Honda G, Roberts T. Musculoskeletal neoplasm: perineoplastic edema versus tumor on dynamic postcontrast MR images with spatial mapping of instantaneous enhancement rates. Radiology. Dec 1995;197(3):831-9. [Medline].
Onikul E, Fletcher BD, Parham DM. Accuracy of MR imaging for estimating intraosseous extent of osteosarcoma. AJR Am J Roentgenol. Nov 1996;167(5):1211-5. [Medline].
Panuel M, Gentet JC, Scheiner C, et al. Physeal and epiphyseal extent of primary malignant bone tumors in childhood. Correlation of preoperative MRI and the pathologic examination. Pediatr Radiol. 1993;23(6):421-4. [Medline].
Saifuddin A, Twinn P, Emanuel R. An audit of MRI for bone and soft-tissue tumours performed at referral centres. Clin Radiol. Jul 2000;55(7):537-41. [Medline].
Schima W, Amann G, Stiglbauer R. Preoperative staging of osteosarcoma: efficacy of MR imaging in detecting joint involvement. AJR Am J Roentgenol. Nov 1994;163(5):1171-5. [Medline].
Ferrari S, Palmerini E. Adjuvant and neoadjuvant combination chemotherapy for osteogenic sarcoma. Curr Opin Oncol. Jul 2007;19(4):341-6. [Medline].
Bhagia SM, Grimer RJ, Davies AM. Scintigraphically negative skip metastasis in osteosarcoma. Eur Radiol. 1997;7(9):1446-8. [Medline].
Jesus-Garcia R, Seixas MT, Costa SR. Epiphyseal plate involvement in osteosarcoma. Clin Orthop. Apr 2000;(373):32-8. [Medline].
Kumta SM, Chow TC, Griffith J. Classifying the location of osteosarcoma with reference to the epiphyseal plate helps determine the optimal skeletal resection in limb salvage procedures. Arch Orthop Trauma Surg. 1999;119(5-6):327-31. [Medline].
Pui MH, Tan MH, Kuan JH. Haematopoietic marrow hyperplasia simulating transarticular skip metastasis in osteosarcoma. Australas Radiol. Aug 1995;39(3):303-5. [Medline].
Ries LA, Smith MA, Gurney JG. Cancer incidence and survival among children and adolescents: United States SEER Program 1975-1995. Washington, DC: National Institutes of Health;. NIH publication 99-4649.
Saifuddin A. The accuracy of imaging in the local staging of appendicular osteosarcoma. Skeletal Radiol. Apr 2002;31(4):191-201. [Medline].
Van der Woude HJ, Bloem JL, Hogendoorn PC. Preoperative evaluation and monitoring chemotherapy in patients with high-grade osteogenic and Ewing's sarcoma: review of current imaging modalities. Skeletal Radiol. 27(2):57-71. [Medline].
Further Reading
Related eMedicine topics:
Osteosarcoma (Orthopedic Surgery)
Osteosarcoma, Variants
Related Medscape topics:
Specialty Site Radiology
Specialty Site Hematology-Oncology
Radiology CME and News
Keywords
classic osteosarcoma, conventional osteosarcoma, chondroblastic osteosarcoma, osteoblastic osteosarcoma, fibroblastic osteosarcoma, high-grade intramedullary osteosarcoma
