Ewing sarcoma is a type of cancer that begins as a growth of cells in the bones and the soft tissue around the bones. Ewing (Yoo-ing) sarcoma mostly happens in children and young adults, although it can happen at any age.

Ewing sarcoma most often begins in the leg bones and in the pelvis, but it can happen in any bone. Less often, it starts in the soft tissues of the chest, abdomen, arms or other locations.

Major advances in the treatment of Ewing sarcoma have improved the outlook for this cancer. Young people diagnosed with Ewing sarcoma are living longer. They sometimes face late effects from the strong treatments. Healthcare professionals often suggest long-term monitoring for side effects after treatment.


Ewing sarcoma signs and 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. These can include:

  • Fever.
  • Losing weight without trying.
  • Tiredness.

When to see a doctor

Make an appointment with a healthcare professional if you or your child has ongoing signs and symptoms that worry you.


It is not clear what causes Ewing sarcoma.

Ewing sarcoma happens when cells develop changes in their DNA. A cell's DNA holds the instructions that tell a cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time.

In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to make many more cells quickly. Cancer cells can keep living when healthy cells would die.

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 is called metastatic cancer.

In Ewing sarcoma, the DNA changes most often affect a gene called EWSR1. If your healthcare professional suspects that you or your child has Ewing sarcoma, the cancer cells may be tested to look for changes in this gene.

Risk factors

Risk factors for Ewing sarcoma include:

  • Young age. Ewing sarcoma can happen at any age. But it is more likely to happen in children and young adults.
  • European ancestry. Ewing sarcoma is more common in people of European ancestry. It's much less common in people of African and East Asian ancestry.

There's no way to prevent Ewing sarcoma.


Complications of Ewing sarcoma and its treatment include the following.

Cancer that spreads

Ewing sarcoma can spread from where it started to other areas. Ewing sarcoma most often spreads to the lungs and to other bones.

Long-term treatment side effects

The strong treatments needed to control Ewing sarcoma can cause major side effects, both in the short and long term. Your healthcare team can help you manage the side effects that happen during treatment. The team also can give you a list of side effects to watch for in the years after treatment.