Osteosarcoma - Childhood

About sarcoma

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 uncontrollably. 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.

About osteosarcoma

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 osteosarcoma begins

It 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 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

  • Medullary tumor, also called a central tumor

  • Peripheral tumor, also called a 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. They each account for less than 5% of all osteosarcomas.

Medullary osteosarcoma subtypes:

  • Conventional central osteosarcoma

  • Telangiectatic osteosarcoma

  • Intraosseous well-differentiated, or low-grade, osteosarcoma

  • Small cell osteosarcoma

Peripheral osteosarcoma subtypes:

  • Parosteal, well-differentiated or low-grade, osteosarcoma. Also called juxtacortical osteosarcoma.

  • Periosteal osteosarcoma that is low grade to intermediate grade

  • High-grade surface osteosarcoma

This section covers osteosarcoma that is diagnosed during childhood. To learn more about other types of bone cancer and soft-tissue sarcoma, visit their specific sections on Cancer.Net.

Looking for More of an Overview?

If you would like additional introductory information, explore these related items. Please note these links take you to other sections on Cancer.Net:

  • ASCO Answers Fact Sheet: Read a one-page fact sheet (available as a 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.