Overview
Ewing (Yoo-ing) sarcoma, also called Ewing's sarcoma, is a rare type of cancer that starts as a growth of cells in the bones or in the soft tissue around the bones. Ewing sarcoma happens most often in children, teenagers and young adults, but it can happen at any age.
Ewing sarcoma most often begins in bone, especially in the pelvis and long bones of the legs. But it can happen in any bone. Less often, it starts outside a bone in soft tissue. Ewing sarcoma is different from other bone cancers, such as osteosarcoma and chondrosarcoma.
Major advances in the treatment of Ewing sarcoma have improved the outlook for this cancer. If the cancer has not spread, treatment is more likely to be successful. But if the cancer has spread, it's more challenging to treat.
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Symptoms
Ewing sarcoma symptoms typically start in and around a bone. This cancer most often affects bones in the legs and the pelvis.
When symptoms happen in and around a bone, they might include:
- A lump in the arm, leg, chest or pelvis.
- Bone pain.
- Break in a bone, also called a fracture.
- Pain, swelling or tenderness near the affected area.
Sometimes Ewing sarcoma causes symptoms that affect the whole body, especially if the cancer has spread. These can include:
- Fever.
- Losing weight without trying.
- Tiredness.
When to seek care
Make an appointment with a healthcare professional if you or your child has ongoing symptoms that worry you.
Causes
It is not clear what causes Ewing sarcoma.
Ewing sarcoma happens when cells develop changes in their DNA. A cell's DNA contains genes that give cells instructions for how to work, including when to grow and divide. Healthy cells follow signals that control growth and tell damaged or unneeded cells when to die.
In cancer cells, changes in DNA can disrupt these instructions. The cells may grow and divide without control and may survive when they should have died.
The cancer cells might form a mass called a tumor. The tumor can grow to invade and destroy healthy body tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it's called metastatic cancer.
In Ewing sarcoma, the DNA changes most often affect a gene called EWSR1. In most cases in children, EWSR1 joins with FLI1, creating what's called a fusion of these genes. Testing tumor cells for these gene fusions can help confirm the diagnosis. These gene changes are not inherited.
Risk factors
The only known risk factors for Ewing sarcoma can't be changed:
- Sex at birth. Ewing sarcoma is more common in males.
- Young age. Ewing sarcoma can happen at any age. But it's more likely to happen in children, teenagers and young adults.
- European ancestry. Ewing sarcoma is more common in people of European ancestry. It is much less common in people with African or East Asian ancestry.
Complications
Complications of Ewing sarcoma include cancer that spreads. The lungs, other bones and bone marrow are common places for Ewing sarcoma to spread.
Prevention
There is no known way to prevent Ewing sarcoma. Researchers have not found lifestyle or environmental factors that cause Ewing sarcoma. Gene changes, such as in the EWSR1 gene, found in Ewing sarcoma are not inherited.
Sept. 30, 2026