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 menu. Think of that menu as a roadmap to this full guide.
Sarcoma is cancer that develops in the tissues that support and connect parts of the body. These include bone, fat, muscle, and soft tissue. Cancer begins when healthy cells change and grow out of control. They form a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant. This means that it can spread to other parts of the body. A benign tumor means the tumor will not spread.
Osteosarcoma is a cancer of the bone that destroys tissue and weakens the bone. It develops from immature bone cells that normally form new bone tissue.
Places where osteosarcoma begins
Osteosarcoma most often starts in the bones around the knee joint, either at the femur, which is the lower end of the thigh bone, or the tibia, which is the upper end of the shin bone. The next most common place osteosarcoma begins is in the humerus. This is the upper arm bone close to the shoulder.
However, osteosarcoma can develop in any bone in the body. Rarely, it occurs as a tumor in the body’s soft tissue, outside the bone.
Types and subtypes of osteosarcoma
There are 2 types of osteosarcoma.
Medullary tumor, also called a central tumor
Peripheral tumor, also called a surface tumor
Each type 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. They each account for less than 5% of all osteosarcomas.
Subtypes of medullary osteosarcoma include:
Conventional central osteosarcoma
Intraosseous well-differentiated, or low-grade, osteosarcoma
Small cell osteosarcoma
Subtypes of peripheral osteosarcoma include:
Parosteal, well-differentiated or low-grade, osteosarcoma. Also called juxtacortical osteosarcoma.
Periosteal osteosarcoma that is low grade to intermediate grade
High-grade surface osteosarcoma
Looking for More of an Introduction?
If you would like more of an introduction, explore these related items. Please note that these links take you to other sections on Cancer.Net:
ASCO Answers Fact Sheet: Read a 1-page fact sheet that offers an introduction to this type of cancer. This fact sheet is available as a PDF, so it is easy to print out.
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.
The next section in this guide is Statistics. It helps explain how many people are diagnosed with this disease and general survival rates. Or, use the menu to choose another section to continue reading this guide.