Ewing’s Sarcoma And PNET


What Is It?

Ewing’s sarcoma is a very rare solid tumor that occurs most often in adolescents and children, although it can occur in adults as well. Although Ewing’s sarcoma develops within bones and formerly was considered to be a bone cancer, it actually arises from a type of primitive nerve cell. For this reason, Ewing’s sarcoma can occur in the body’s soft tissues as well. PNET is the shortened way of referring to a similar tumor called primitive neuroectodermal tumor. It also is known as peripheral neuroepithelioma. While they were previously described as separate cancers, it is now thought that Ewing’s sarcoma and PNET represent different types of the same cancer. Their treatment and response to therapy are similar. Askin’s tumor is the name given to PNET tumors of the chest wall.

Ewing’s sarcoma usually develops in the arms or legs, but sometimes it occurs in the pelvis, ribs, spine and, in rare cases, other bones or soft tissues. At the time of diagnosis, about 23 percent to 26 percent of Ewing’s sarcomas have already spread (metastasized) to another site, usually to the lungs, a second bone or the bone marrow.

Like other cancers, Ewing’s sarcoma is made up of abnormal cells that multiply out of control. The cells of Ewing’s sarcoma show a changed pattern of DNA. This change, called a translocation, usually involves a rearrangement of DNA pieces between chromosome 22 and chromosome 11. The reason for this chromosome problem is a mystery. The genetic problem is not inherited. It develops after birth. There is no evidence that this cancer is related to exposure to radiation, chemicals or any other environmental factor. Ewing’s sarcoma is very rare, with an average of only 150 new cases reported per year in the United States. It is almost always a tumor of childhood or adolescence, with 64 percent of cases occurring in people between the ages of 10 and 20 and 27 percent before age 10. Only 9 percent of people with Ewing’s sarcoma are adults, usually between the ages of 20 and 30. About 96 percent of people with this cancer are white.


Symptoms of Ewing’s sarcoma include:

  • Persistent pain and swelling in an arm or leg, which may occur at rest and may even awaken the patient from sleep
  • A firm lump on an arm or leg, sometimes with local tenderness
  • A limp, if the tumor affects the leg
  • Difficulty breathing, if the tumor affects the ribs
  • Fever (in 28 percent of patients)
  • Weight loss

In physically active or competitive children, the pain and swelling of Ewing’s sarcoma can be mistaken for symptoms of a sports injury. In patients who have a fever, symptoms of Ewing’s sarcoma often are confused with those of osteomyelitis (bone infection).


After reviewing your symptoms, your doctor will examine you, paying special attention to the painful, swollen area. Your doctor will check the affected area for warmth, redness, degree of swelling, tenderness, limitation of motion and any signs of joint involvement. The physical examination usually will be followed by an X-ray of the area and tests of your blood and urine. In most cases, the results of laboratory tests are fairly normal because no specific blood or urine tests can confirm the diagnosis of Ewing’s sarcoma. However, the X-ray usually will show either the typical pattern of a Ewing’s sarcoma affecting a bone or some other abnormality, usually an area of bone destruction, which indicates the presence of a bone tumor.

Once your doctor has found X-ray evidence of a bone tumor, he or she will refer you to a major medical center that has the facilities, personnel and experience to treat bone cancer. There you will have further tests, such as magnetic resonance imaging (MRI) scans of the affected area to determine how far the tumor has invaded local structures. You probably also will have a chest X-ray, a radionuclide bone scan and a bone-marrow biopsy to check for any metastases to your lungs, other bones or the bone marrow. A biopsy involves removing a small amount of tissue to be examined in a laboratory.

After these tests, you will have a biopsy of the tumor to confirm the diagnosis of Ewing’s sarcoma.

Expected Duration

Once it develops, Ewing’s sarcoma will continue to grow until it is treated. If not treated, this cancer can spread to the lungs and to other bones.


There is no way to prevent Ewing’s sarcoma.


In most cases, Ewing’s sarcoma is treated using chemotherapy, radiation therapy and/or surgery.

To stop the tumor from growing or spreading, it either can be removed surgically or treated with radiation. When surgery is performed, it is usually limb-sparing surgery, which removes the cancerous tumor without amputating the limb. The area from which the cancer is removed is filled with a bone graft or prosthesis to allow the limb to remain as functional as possible. If the cancer has spread to the lungs, it can be removed through open chest surgery (thoracotomy). Radiation therapy is also highly effective in treating Ewing’s sarcoma. Which treatment is used depends on the size of the tumor and how much it has invaded surrounding tissues.

Chemotherapy usually is given in addition to radiation and/or surgery to treat Ewing’s sarcoma. A variety of chemotherapy drugs may be recommended. These drugs decrease the chance that the tumor will spread or grow in other areas of the body, such as the lungs or bone marrow.

If treatment is successful, the patient must be monitored closely through many years of follow-up visits. This is because Ewing’s sarcoma can return as late as 10 years after the initial diagnosis. Also, a second cancer may develop in the area of radiation treatment, or the patient may suffer late side effects from the drugs that were used in chemotherapy.

When To Call A Professional

Call your doctor if you or anyone in your family develops an area of persistent or unexplained pain and swelling in a bone, with or a without fever.


After proper treatment, 50 percent to 60 percent of patients without metastases (cancer spread) survive at least five years. This percentage increases to 80 percent if the tumor is located below the elbow or below the midcalf. Patients with metastases usually have a poorer prognosis, with a five-year survival rate of approximately 25 percent.

Johns Hopkins patient information

Last revised:

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.