ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Childhood Osteosarcoma. To see other pages, use the colored boxes on the right side of your screen. Think of those boxes as a roadmap to this full guide. Or, click “Next” at the bottom of each page.
Sarcoma is cancer that develops in the tissues that support and connect parts of the body, including bone, fat, muscle, and soft tissue. Cancer begins when normal cells change and grow uncontrollably, forming a mass called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body).
Osteosarcoma is a cancer of the bone that destroys tissue and weakens the bone. Osteosarcoma develops from immature bone cells that normally form new bone tissue. Osteosarcoma most often starts in the bones around the knee joint, at the lower end of the femur (thigh bone) or the upper end of the tibia (shin bone). The second most common place is in the humerus (upper arm bone close to the shoulder). However, osteosarcoma can develop in any bone in the body. Rarely, it can also occur as a tumor in the soft tissue of the body, outside the bone.
Osteosarcoma is described as either a medullary (central) tumor or a peripheral (surface) tumor. Each has different subtypes. The type and subtype of osteosarcoma is determined by looking at the tumor cells through a microscope. The most common subtype is called conventional central osteosarcoma. The other subtypes are much less common, each accounting for less than 5% of all osteosarcomas.
Medullary osteosarcoma subtypes include:
- Conventional central osteosarcoma
- Telangiectatic osteosarcoma
- Intraosseous well-differentiated (low-grade) osteosarcoma
- Small cell osteosarcoma
Peripheral osteosarcoma subtypes include:
- Parosteal (juxtacortical) well-differentiated (low-grade) osteosarcoma
- Periosteal (low-grade to intermediate-grade) osteosarcoma
- High-grade surface osteosarcoma
Looking for More of an Overview?
If you would like additional introductory information, explore these related items. Please note these links will take you to other sections on Cancer.Net:
- ASCO Answers Fact Sheet: Read a one-page fact sheet (available in PDF) that offers an easy-to-print introduction to this type of cancer.
- Cancer.Net Patient Education Video: View a short video led by an ASCO expert in childhood cancer that provides basic information and areas of research.
Or, choose “Next” (below, right) to continue reading this detailed section. To select a specific topic within this section, use the colored boxes located on the right side of your screen.