Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body. To learn more about how cancers start and spread, see What Is Cancer? For information about the differences between childhood cancers and adult cancers, see Cancer in Children.

The Ewing family of tumors is a group of cancers that start in the bones or nearby soft tissues that share some common features. These tumors can develop at any age, but they are most common in the early teen years.

The main types of Ewing tumors are:

• Ewing sarcoma of bone: Ewing sarcoma that starts in a bone is the most common tumor in this family. This type of tumor was first described by Dr. James Ewing in 1921, who found it was different from the more common bone tumor, osteosarcoma. Seen under a microscope, its cells looked different from osteosarcoma cells. It was also more likely to respond to radiation therapy.
• Extraosseous Ewing tumor (EOE): Extraosseous Ewing tumors start in soft tissues around bones, but they look and act very much like Ewing sarcomas in bones. They are also known as extraskeletal Ewing sarcomas.
• Peripheral primitive neuroectodermal tumor (PPNET): This rare childhood cancer also starts in bone or soft tissue and shares many features with Ewing sarcoma of bone and EOE. Peripheral PNETs that start in the chest wall are known as Askin tumors.

Researchers have found that the cells that make up Ewing sarcoma, EOE, and PPNET are very similar. They tend to have the same DNA (gene) abnormalities and share similar proteins, which are rarely found in other types of cancers. That’s why these 3 cancers are thought to develop from the same type of cells in the body. There are slight differences among these tumors, but they're all treated the same way.

Most Ewing tumors occur in the bones. The most common sites are:

• The pelvis (hip bones)
• The chest wall (such as the ribs or shoulder blades)
• The legs, mainly in the middle of the long bones

In contrast, osteosarcoma usually occurs at the ends of the long bones, especially around the knees. Extraosseous Ewing tumors can occur almost anywhere.

Most Ewing tumors occur in children and teens, but they can also occur in adults. This information focuses on the Ewing family of tumors in children and teens, but most of the information here (including much of the treatment information) applies to Ewing tumors in adults as well.

Other types of bone cancers

Several other types of cancers can start in the bones.

Osteosarcomas are the most common bone cancer in children and teens. They are described in Osteosarcoma.

Most other types of bone cancers are usually found in adults and are rare in children. These include:

• Chondrosarcoma (cancer that develops from cartilage)
• Malignant fibrous histiocytoma
• Fibrosarcoma
• Chordoma
• Malignant giant cell tumor of bone

For more information on these cancers, see Bone Cancer.

Many types of cancer that start in other organs of the body can spread to the bones. These are sometimes referred to as metastatic bone cancers, but they are not true bone cancers. For example, if a rhabdomyosarcoma (a cancer that starts in muscle cells) spreads to the bones, it is still rhabdomyosarcoma and is treated like rhabdomyosarcoma. For more information, see Advanced Cancer, Metastatic Cancer, and Bone Metastasis.

Ewing tumors are usually found because of signs or symptoms a person is having. If the doctor suspects a tumor, exams and tests will be needed to find out for sure.

Medical history and physical exam

If you or your child has signs or symptoms that could be from a tumor, the doctor will want to get a complete medical history to find out more about the symptoms and how long they have been present.

The doctor will also do a complete physical exam, paying special attention to any areas causing pain or swelling.

If a doctor suspects a bone tumor (or another type of tumor), more tests will be done to find out. These might include imaging tests, biopsies, and/or lab tests.

Imaging tests

Imaging tests (such as x-rays, MRI scans, CT scans, bone scans, and PET scans) create pictures of the inside of the body. Imaging tests might be done for many reasons, including:

• To help find out if a suspicious area might be cancer
• To determine the extent of a tumor or learn how far a cancer may have spread
• To help determine if treatment is working

Patients who have or might have a Ewing tumor will have one or more of these tests.

X-rays

If a bone lump doesn’t go away or the doctor suspects a bone tumor for some other reason, an x-ray of the area will probably be the first test done. A radiologist (doctor who specializes in reading imaging tests) can usually spot a bone tumor on an x-ray and can often tell if it is likely to be a Ewing tumor. But other imaging tests might be needed as well.

Even if an x-ray strongly suggests a Ewing bone tumor, a biopsy (described below) is still needed to confirm that it is cancer rather than some other problem, such as an infection.

Magnetic resonance imaging (MRI) scan

MRI scans create detailed images using radio waves and strong magnets instead of x-rays, so there is no radiation involved. A contrast material called gadolinium may be injected into a vein before the scan to help see details better.

An MRI scan is often done to get a better look an abnormal area seen on an x-ray. MRI scans usually can show if it is likely to be a tumor, an infection, or some type of bone damage from other causes. MRIs can also help determine the extent of a tumor, as they show the detail inside bones as well as the muscle, fat, and connective tissue around the tumor. Knowing the extent of the tumor is very important when planning surgery or radiation therapy.

MRI scans might also be done to see if the cancer has spread to other areas, such as the spine or pelvis (hip area). MRI scans can also be used during and after treatment to see how well the tumor is responding.

Computed tomography (CT) scan

A CT scan combines many x-ray pictures to make detailed cross-sectional images of parts of the body, including soft tissues such as muscles. A contrast material may be injected into a vein before the scan to help see details better.

CT scans of the chest are often used to see if a Ewing tumor has spread to the lungs. MRI scans are usually a bit better at defining the extent of the main tumor itself, but a CT scan of the tumor may be done as well.

Bone scan

For a bone scan, a small amount of low-level radioactive material is injected into the blood and travels to the bones. A special camera can detect the radioactivity and creates a picture of the skeleton. 

Areas of active bone changes appear as “hot spots” on the skeleton because they attract the radioactivity. These areas may suggest the presence of cancer, but other bone diseases can also cause the same pattern. To be sure, other tests such as plain x-rays or MRI scans, or even a bone biopsy, might be needed.

A bone scan can help show if a cancer has spread to bones in other parts of the body, and might be part of the workup for a Ewing tumor. This test is useful because it can show the entire skeleton at once. (A positron emission tomography [PET] scan can often provide similar information, so a bone scan might not be needed if a PET scan is done.)

Positron emission tomography (PET) scan

For a PET scan, a form of radioactive sugar (known as FDG) is injected into the blood. Because cancer cells are growing quickly, they absorb large amounts of the sugar. A special camera can then create a picture of areas of radioactivity in the body. The picture is not detailed like a CT or MRI scan, but it provides helpful information about the whole body.

PET scans can be very helpful in showing the spread of Ewing tumors and in finding out whether abnormal areas seen on other imaging tests (such as a bone scan or CT scan) are tumors. PET scans can also be repeated during treatment to see how well it is working.

Some newer machines can do a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed appearance of that area on the CT scan.

Biopsy of the tumor

The results of imaging tests might strongly suggest a Ewing tumor, but a biopsy (removing some of the tumor for viewing under a microscope and other lab testing) is the only way to be certain.

If the tumor is in a bone, it is very important that an orthopedic surgeon experienced in treating bone tumors does the biopsy. Whenever possible, the biopsy and the surgery to treat the cancer should be planned together, and the same surgeon should do both. Proper planning of the biopsy can help prevent later complications and might reduce the amount of surgery needed later on.

There are a few ways to get a sample of the tumor to diagnose Ewing tumors.

Incisional biopsy

For most suspected Ewing tumors, an incisional biopsy (taking out only a piece of the tumor) is done. This can be done in a couple of ways:

• Surgical (open) biopsy: The surgeon cuts away a piece of the tumor through an opening on the skin.
• Needle (closed) biopsy: The surgeon puts a large, hollow needle through the skin and into the tumor to remove a piece of it.

Incisional biopsies are often done while the patient is under general anesthesia (in a deep sleep), but in older teens and adults they are sometimes done with just sedation and a local anesthetic (numbing medicine).

Excisional biopsy

In very rare cases, if the tumor is small enough and in a good location, the surgeon can completely remove it while the patient is under general anesthesia (asleep). This is called an excisional biopsy.

If general anesthesia is going to be used for the biopsy, the surgeon may also plan other procedures while the patient is asleep to avoid having to do them as separate operations later on. For example, if the tumor is thought to have spread to the chest or elsewhere, the surgeon may take biopsy samples of these suspected tumors. The doctor might also do a bone marrow biopsy (see below) at this time to see if the cancer has spread to the bone marrow.

During the biopsy (while the patient is still asleep), the biopsy samples can be checked quickly under a microscope for cancer. If it looks like a Ewing tumor, the patient will very likely need chemotherapy as part of treatment, so the surgeon may place a small flexible tube, known as a central venous catheter, into a large vein in the chest area during the same operation. The catheter end lies just under or outside on the skin. It can stay in place for several months during treatment. The catheter gives doctors and nurses easier access to the vein, so not as many needle sticks are needed to give chemotherapy or do blood draws later.

Bone marrow aspiration and biopsy

These tests are used to see if the cancer cells have spread into the bone marrow, the soft inner parts of certain bones. The tests might be done once a Ewing tumor has been diagnosed because it is important to know if the tumor has spread to the bone marrow.

Bone marrow aspiration and biopsy are usually done at the same time. In most cases the marrow samples are taken from the back of both of the pelvic (hip) bones. These tests may be done during the surgery to biopsy or treat the main tumor (while the patient is still under anesthesia), or they may be done as a separate procedure.

If the bone marrow aspiration is being done as a separate procedure, the patient lies on a table (on his or her side or belly). The area over the hip is cleaned, and the skin and the surface of the bone are numbed with a local anesthetic, which may cause a brief stinging or burning sensation. Children may also be given other medicines to make them sleepy, or they might even be asleep during the procedure. A thin, hollow needle is then inserted into the bone, and a syringe is used to suck out a small amount of liquid bone marrow.

A bone marrow biopsy is usually done just after the aspiration. A small piece of bone and marrow is removed with a slightly larger needle that is pushed down into the bone. Once the biopsy is done, pressure is applied to the site to help stop any bleeding.

Samples from the bone marrow are sent to a pathology lab, where they are looked at and tested for cancer cells.

Testing biopsy samples

A doctor called a pathologist looks at all biopsy specimens under a microscope to see if they contain cancer cells. If cancer is found, the specific type of cancer can often be determined as well. But because cells from Ewing tumors share many of the same features as cells from other types of cancer, more lab tests are often needed.

Immunohistochemistry

For this test, a portion of the biopsy sample is treated with special proteins (antibodies) that attach to substances found on Ewing tumor cells but not on other cancers. Chemicals (stains) are then added so that cells containing these substances change color and can be seen under a microscope. This lets the pathologist know that the cells are from a Ewing tumor.

Chromosome tests

Normal human cells have 23 pairs of chromosomes (strands of DNA), each of which is a certain size and looks a certain way under the microscope. Ewing tumor cells almost always have chromosome translocations, where 2 chromosomes swap pieces of their DNA. In most cases, the cells have translocations between chromosomes 22 and 11. Less often, the translocation is between other chromosomes. Finding these changes can help doctors tell Ewing tumors from other types of cancer. Other types of chromosome changes can also be found in some Ewing tumors.

Cytogenetics: In this lab test, the cells are looked at under a microscope to see if the chromosomes have any abnormalities. A drawback of this test is that it usually takes about 2 to 3 weeks because the cells must grow in lab dishes for a couple of weeks before their chromosomes are ready to be viewed under the microscope. 

Fluorescent in situ hybridization (FISH): This test looks more closely at tumor cell DNA using special fluorescent dyes that only attach to specific genes or parts of chromosomes. FISH can find most chromosome changes (such as translocations) that can be seen in standard cytogenetic tests, as well as some gene changes too small to be seen with cytogenetic testing. FISH is very accurate and can usually provide results within a couple of days.

Polymerase chain reaction (PCR): PCR is a very sensitive test that is often able to detect very small numbers of cells with translocations, which wouldn’t be detected by cytogenetics.

PCR is also useful in looking for cancer remaining or coming back after treatment. For example, if PCR testing of a bone marrow sample after treatment finds cells with a typical Ewing tumor translocation, it’s likely that the cancer hasn’t been cured, and that more treatment is needed.

Blood tests

No blood test can be used to diagnose Ewing tumors. But certain blood tests may be helpful once a diagnosis has been made.

A complete blood count (CBC) measures the levels of white blood cells, red blood cells, and platelets in the blood. An abnormal CBC result at the time of diagnosis might suggest the cancer has spread to the bone marrow, where these blood cells are made.

A blood test for levels of an enzyme called lactate dehydrogenase (LDH) is typically done at diagnosis. A high LDH level is often a sign that there is more cancer in the body.

Standard blood tests are done often to check a patient’s general health both before treatment (especially before surgery) and during treatment (such as chemotherapy) to look for possible problems or side effects. These tests often include a CBC to monitor bone marrow function and blood chemistry tests to measure how well the liver and kidneys are working.

Ewing tumors are often found because of the symptoms they cause.

Pain

Most children and teens with Ewing tumors will have pain in the area of the tumor. Ewing tumors occur most often in the pelvis (hip bones), the chest wall (such as the ribs or shoulder blades), and the legs (mainly in the middle of the long bones), but they can also start in other parts of the body.

Bone pain can be caused by the tumor spreading under the outer covering of the bone (periosteum), or the pain can be from a break (fracture) in a bone that has been weakened by the tumor.

Lump or swelling

Over time, most Ewing bone tumors and almost all non-bone (soft tissue) Ewing tumors cause a lump or swelling, which is more likely to be noticed in tumors in the arms or legs. The lump is often soft and feels warm. Tumors in the chest wall or pelvis might not be noticed until they have grown quite large.

Other symptoms

Ewing tumors can also cause other symptoms, some of which are more common in tumors that have spread:

• Fever
• Feeling tired
• Weight loss

Rarely, tumors near the spine can cause back pain, as well as weakness, numbness, or paralysis in the arms or legs. Tumors that have spread to the lungs can cause shortness of breath.

Many of the signs and symptoms of Ewing tumors are more likely to be caused by something else. Still, if your child has any of these symptoms, see a doctor so that the cause can be found and treated, if needed.

Because many of these signs and symptoms can be confused with normal bumps and bruises or bone infections, Ewing tumors might not be recognized right away. For example, the doctor might try giving antibiotics first if an infection is suspected. The correct diagnosis might not be made until the signs and symptoms don’t go away (or get worse) and the bone is then x-rayed.

About 1% of all childhood cancers are Ewing tumors. About 200 children and teens are diagnosed with Ewing tumors in the United States each year.

Most Ewing tumors occur in teens, but they can also affect younger children, as well as adults (mainly in their 20s and 30s).

Slightly more males than females develop these cancers. These tumors are much more common among whites, either non-Hispanic or Hispanic. This disease is very rare among African Americans, and it also seldom occurs in other racial groups.

Survival statistics for these tumors are discussed in Survival Rates for Ewing Tumors, by Stage.

Visit the American Cancer Society’s Cancer Statistics Center for more key statistics.

A risk factor is anything that affects a person’s chance of getting a disease such as cancer. Different cancers have different risk factors.

Lifestyle-related risk factors such as body weight, physical activity, diet, and using tobacco play a major role in many adult cancers. But these factors usually take many years to influence cancer risk, and they are not thought to play much of a role in cancers that tend to affect children and teens, including Ewing tumors.

Studies of children with Ewing tumors have not found links to radiation, chemicals, or any other environmental exposures.

Some types of cancer tend to run in some families. But genetic changes passed along within families are not an important risk factor for Ewing tumors. Although the gene changes that cause most Ewing tumors are known (see What Causes Ewing Tumors?), these changes are not inherited from a parent.

Race/ethnicity

Ewing tumors are rare overall, but they are much more common among whites (either non-Hispanic or Hispanic) than among Asian Americans or African Americans. The reason for this is not known.

Gender

These cancers are slightly more common in males than in females.

Age

Ewing tumors can occur at any age, but they are most common in teens and are less common among young adults and young children. They are rare in older adults.

The cause of Ewing tumors is not fully understood, but researchers are learning how certain changes in a cell’s DNA can cause the cell to become cancerous. DNA is the chemical in each of our cells that makes up our genes. Genes tell our cells how to function. They are packaged in chromosomes, which are long strands of DNA in each cell. We normally have 23 pairs of chromosomes in each cell (one set of chromosomes comes from each parent). We usually look like our parents because they are the source of our DNA. But DNA affects more than how we look.

Some genes control when our cells grow, divide into new cells, and die:

• Genes that help cells grow, divide, or stay alive are called oncogenes.
• Genes that slow down cell division or make cells die at the right time are called tumor suppressor genes.

Cancers can be caused by changes in the cell’s DNA that turn on oncogenes or turn off tumor suppressor genes.

Researchers have found chromosome changes that lead to Ewing tumors, but these changes are not inherited. Instead, they develop in a single cell after a child is born, for unknown reasons.

Nearly all Ewing tumor cells have changes that involve the EWSR1 gene, which is found on chromosome 22. Most often, the change is a swapping of pieces of DNA (called a translocation) between chromosomes 22 and 11. Less often, the swap is between chromosomes 22 and 21, or rarely, between 22 and another chromosome. The translocation moves a certain piece of chromosome 11 (or another chromosome) just next to the EWSR1 gene on chromosome 22, causing the EWSR1 gene to be turned on all the time. Activation of the EWSR1 gene leads to overgrowth of the cells and to the development of this cancer, but the exact way in which this happens is not yet clear.

In a very small portion of Ewing tumors, the cells have translocations that involve the FUS gene (on chromosome 16) instead of the EWSR1 gene.

Lab tests can be used to find chromosome translocations in Ewing tumor cells (see Tests for Ewing Tumors). If doctors are not sure if a tumor belongs to the Ewing family, they can use these tests on tumor samples to look for translocations and confirm the diagnosis.

The gene changes that lead to Ewing tumors are now fairly well known, but it’s still not clear what causes these changes. It might just be a random event that sometimes happens inside a cell, without having an outside cause. There are no known lifestyle-related or environmental causes of Ewing tumors, so it is important to remember that at this time, nothing could have been done to prevent these cancers.

Ewing tumors are uncommon, and there are no widely recommended screening tests for these cancers. (Screening is testing for cancer in people without any symptoms.) Still, Ewing tumors sometimes cause symptoms that allow them to be found early (before they have clearly spread to other parts of the body).

The most common symptom of a Ewing tumor is pain in the area of the tumor. Sometimes the tumor shows up as a lump or swelling on an arm or leg, or on the chest. Sometimes the lump feels warmer than the rest of the body, and sometimes the child has other symptoms like a fever or not feeling well.

Of course, children and teens often get sore or have lumps and bumps from normal activities. But pains or lumps that don’t go away (or that get worse) should be checked by a doctor. The same is true if a lump feels warm and/or the child has a fever. These symptoms are more likely to have other causes, such as an infection, but they need to be checked by a doctor so that the cause can be found and treated, if needed.

It’s important to have honest, open discussions with your cancer care team. Ask any question, no matter how minor it might seem. For instance, consider these questions:

Before getting a bone biopsy

• How much experience do you have doing this type of biopsy? 
• Are you part of a team that treats bone cancers?
• What will happen during the biopsy?
• How long will it take to get the results from the biopsy?

If a Ewing tumor has been diagnosed

• What kind of Ewing tumor do I (does my child) have?
• Where exactly is the tumor?
• Has the cancer spread beyond where it started?
• What is the stage of the cancer and what does that mean?
• Do we need any other tests before we can decide on treatment?
• How much experience do you have treating this type of cancer?
• Who else will be on the treatment team, and what do they do?

When deciding on a treatment plan

• What are our treatment options?
• What do you recommend and why?
• Are there any clinical trials we should consider? How can we find out more about them?
• What’s the goal of treatment?
• Should we get a second opinion? How do we do that? Can you recommend someone?
• How soon do we need to start treatment?
• What should I (we) do to be ready for treatment?
• How long will treatment last? What will it be like? Where will it be done?
• How will treatment affect our daily lives?
• What are the risks and side effects of the suggested treatments?
• Which side effects start shortly after treatment and which ones might develop later on?
• Will treatment affect my child’s ability to grow and develop?
• Will treatment affect my child’s future ability to have children?

During and after treatment

Once treatment begins, you’ll need to know what to expect and what to look for. Not all of these questions may apply, but getting answers to the ones that do may be helpful.

• How will we know if the treatment is working?
• Is there anything we can do to help manage side effects?
• What symptoms or side effects should we tell you about right away?
• How can we reach you or someone on your team on nights, weekends, or holidays?
• Who can we talk to if we have questions about costs, insurance coverage, or social support? 
• What are the chances of the cancer coming back after treatment? What might our options be if this happens?
• What type of follow up and rehab will be needed after treatment?
• Are there nearby support groups or other families who have been through this that we could talk to?

Along with these sample questions, be sure to write down some of your own. For instance, you might want more information about recovery times so that you can plan your work or school schedules.

Keep in mind that doctors aren’t the only ones who can give you information. Other health care professionals, such as nurses and social workers, can answer some of your questions. To find more about speaking with your health care team, see The Doctor-Patient Relationship.