Ewing family of tumors (EFT) is a group of cancers that affect the bones or nearby soft tissue. Cancer occurs when cells in the body become abnormal and multiply without control or order. The cells form a growth of tissue, called a tumor. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). Depending on the type, EFT develops in different places. EFT includes:

• Ewing tumor of the bones (also called Ewing sarcoma), the most common type of EFT
• Extraosseous Ewing (EOE), a tumor that grows in soft tissues outside the bone
• Peripheral primitive neuroectodermal tumor (PPNET), a rare tumor found in the bones and soft tissues. This includes Askin's tumor, which is a PPNET of the chest wall.

EFT of the bone occurs most often in the leg, spine, rib, or pelvis. EFT of the soft tissue is usually found in the thigh, pelvis, spine, chest, or foot. Specifically, about 41% of EFT develops in a leg and foot, 26% in the pelvis, 16% in the chest wall, 9% in an arm or hand, 6% in the spine, and 2% in the skull.

This section covers EFT diagnosed in children and teenagers. For more information about adults, please read the Guide to Bone Cancer [2].

Find out more about basic cancer terms used in this section [3].

Looking for More of an Overview?

If you would like additional introductory information, explore these related items on Cancer.Net:

• ASCO Answers Fact Sheet [4]: Read a one-page fact sheet (available in PDF) that offers an easy-to-print introduction for this type of cancer.

• Cancer.Net Patient Education Videos: View short videos on childhood cancer treatment [5], childhood cancer survivorship [6], and adolescents/young adults [7] with cancer.
• Cancer.Net En Español [8]: Infórmase sobre sarcoma de tejido blando [8].

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