Ewing tumors are usually found as a result of signs or symptoms that a child or teen is having. If a tumor is suspected, tests will be needed to confirm the diagnosis.

Signs and symptoms of Ewing tumors

The most common symptom of a Ewing tumor is pain at the tumor site. Most patients with bone tumors have bone pain. The pain may be caused by the tumor spreading under the tissue covering the bone (periosteum), or the pain may be from a break or a fracture of a bone that has been weakened by the tumor.

Most Ewing bone tumors and almost all of the non-bone Ewing tumors (of soft tissue) cause a swelling or mass, which is more likely to be noticed in tumors in the arms or legs. The tumor may feel soft and warm. Tumors in the chest wall and pelvic tumors may not be noticeable until the tumor has grown quite large.

If the tumor has spread, the child may have a fever, feel very tired, or even lose weight. Rarely, tumors near the spine can cause weakness or paralysis, while 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 evaluated and treated, if needed.

Because many of these signs and symptoms are also typical of normal bumps and bruises or bone infections, Ewing tumors may not be recognized right away. The correct diagnosis is often made only after the child's condition does not quickly go away or does not improve with antibiotics, at which time the bone is x-rayed.

Medical history and physical exam

If your child has signs or symptoms that may suggest a tumor, the doctor will want to take a complete medical history to check for symptoms. A physical exam can provide information about the tumor and other health problems. For example, the doctor may be able to see or feel an abnormal mass.

If symptoms and/or the results of the physical exam suggest a Ewing tumor (or other tumor) might be present, more involved tests will probably be done. These might include imaging tests, biopsies, and/or lab tests.

Imaging tests

Imaging tests use x-rays, magnetic fields, or radioactive substances to create pictures of the inside of the body. Imaging tests may be done for a number of reasons, including:

• to help find out if a suspicious area might be cancerous
• to learn how far cancer may have spread
• to help determine if treatment has been effective

Most patients who have or may have cancer 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, the doctor will probably order an x-ray. A radiologist (doctor who specializes in reading imaging tests) can usually identify a bone tumor on an x-ray and can often recognize a Ewing tumor that involves bone. But other imaging tests may be needed as well.

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

Magnetic resonance imaging (MRI) scan

Often, an MRI scan is done to better define a mass seen on an x-ray. MRI scans can usually tell if the mass is likely to be a tumor, an infection, or some type of bone damage from other causes. MRI scans can also help determine the exact extent of a tumor, as they provide a detailed view of the marrow inside bones and the muscle, fat, and connective tissue around the tumor. Defining the extent of the tumor is important when planning surgery or radiation therapy. MRI is also useful in seeing the effect of the treatment on the tumor.

MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays, so there is no radiation involved. The energy from the radio waves is absorbed by the body and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into a very detailed image of parts of the body. A contrast material called gadolinium may be injected into a vein before the scan to better see details.

MRI scans may take up to an hour to have done. Your child may have to lie inside a narrow tube, which is confining and can be distressing. Newer, more open MRI machines can help with this, but the test still requires staying still for long periods of time. The machines also make buzzing and clicking noises that may be disturbing. Sometimes, younger children are given medicine to help keep them calm or even asleep during the test.

Computed tomography (CT or CAT) scan

CT scans are often used to see if a Ewing tumor has spread to the lungs, lymph nodes, or liver.

The CT scan is an x-ray test that produces detailed cross-sectional images of parts of the body. Instead of taking one picture, like a regular x-ray, a CT scanner takes many pictures as it rotates around your child while he or she lies on a table. A computer then combines these pictures into images of slices of the part of the body being studied. Unlike a regular x-ray, a CT scan creates detailed images of the soft tissues in the body.

Before the scan, your child may be asked to drink a contrast solution and/or get an intravenous (IV) injection of a contrast dye that helps better outline abnormal areas in the body. If the contrast dye is to be injected, your child may need an IV line. The contrast may cause some flushing (a feeling of warmth, especially in the face). Some people are allergic and get hives. Rarely, more serious reactions like trouble breathing or low blood pressure can occur. Be sure to tell the doctor if your child has any allergies or has ever had a reaction to any contrast material used for x-rays.

CT scans take longer than regular x-rays, but not as long as MRI scans. Your child will need to lie still on a table while they are being done. During the test, the table moves in and out of the scanner, a ring-shaped machine that completely surrounds the table. Some people feel a bit confined by the ring they have to lie in while the pictures are being taken. In some cases, your child may need to be sedated before the test to stay still and help make sure the pictures come out well.

Spiral CT (also known as helical CT) is now available in many medical centers. This type of CT scan uses a faster machine. The scanner part of the machine rotates around the body continuously, allowing doctors to collect the images much more quickly than with a standard CT. This lowers the chance of blurred images occurring as a result of breathing motion. It also lowers the dose of radiation received during the test. The image slices are also thinner, which yields more detailed pictures.

Bone scan

A bone scan can help show if a cancer has metastasized (spread) to the bones, and is often part of the workup for children with a Ewing tumor. This test is useful because it provides a picture of the entire skeleton at once.

For this test, a small amount of low-level radioactive material is injected into a vein (intravenously, or IV). The substance settles in areas of damaged bone throughout the entire skeleton over the course of a couple of hours. Your child then lies on a table for about 30 minutes while a special camera detects 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 make an accurate diagnosis, other imaging tests such as plain x-rays or MRI scans, or even a bone biopsy might be needed.

Positron emission tomography (PET) scan

For a PET scan, glucose (a form of sugar) that contains a radioactive atom is injected into the blood. The amount of radioactivity used is very low. Because cancer cells in the body are growing quickly, they absorb large amounts of the radioactive sugar. A special camera can then create a picture of areas of radioactivity in the body. The picture is not finely 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, in finding out whether abnormal areas seen on a bone scan or CT scan are tumors, and also in following the response to treatment.

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 with the more detailed appearance of that area on the CT.

Biopsy of the tumor

Although the results of imaging tests may strongly suggest that cancer is present, a biopsy (removing some of the tumor for viewing under a microscope and other lab testing) is the only way to be certain. A biopsy is also the best way to tell Ewing tumors from other types of cancer.

If the tumor involves bone, it is very important that a doctor experienced in treating Ewing tumors perform the biopsy. Proper planning of the biopsy location and technique can prevent later complications and reduce the amount of surgery needed later on during treatment.

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

Excisional biopsy

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

Incisional biopsy

If the tumor is large or cannot be easily removed, an incisional biopsy (taking only a piece of the tumor) is more likely to be done. The surgeon can do this either during an operation by cutting away a piece of the tumor through an opening on the skin (known as an open biopsy) or by placing a large, hollow needle through the skin and into the tumor (known as a needle biopsy or closed biopsy). Although incisional biopsies in adults are sometimes done using a local anesthetic (numbing medicine), in children they are more often done while the child is under general anesthesia (asleep).

If a child is going to have general anesthesia for the biopsy, the surgeon may also plan other procedures while the child is asleep to avoid having to do them as separate procedures later on. For example, if the tumor is thought to have spread to the chest or elsewhere, the surgeon may take a biopsy of these suspected lumps when the child is still asleep. The doctor may also do a bone marrow biopsy (see below) to see if the cancer has spread to other bones.

During the biopsy (while the child is still asleep), a pathologist can take a quick look at the tissue sample under the microscope. If it is a Ewing tumor, the surgeon may place a central venous access catheter into a main blood vessel in the chest area during the same operation. The catheter end lies just under or outside on the skin, which gives doctors and nurses easier access to the vein. This is better for the child when chemotherapy is given at a later time because they will get fewer needle sticks. (See the discussion on chemotherapy in the section, "How are Ewing tumors treated?").

Bone marrow aspiration and biopsy

These tests look to see if the cancer cells have spread into the bone marrow, the soft inner parts of certain bones. The tests aren't usually done to diagnose Ewing tumors, but they may be done once the diagnosis is made, 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 as a separate procedure, or they may be done during the surgery to biopsy or treat the main tumor (while the child is still under anesthesia).

If the bone marrow aspiration is being done as a separate procedure, the child lies on a table (on his or her side or belly). After the area is cleaned, the skin over the hip and the surface of the bone are numbed with a local anesthetic, which may cause a brief stinging or burning sensation. In most cases, the child is also given other medicines for pain or 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 twisted as it is pushed down into the bone. Once the biopsy is done, pressure will be 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 the biopsy samples

A pathologist (a doctor specializing in using lab tests to diagnose diseases) looks at all biopsy specimens under a microscope to see if cancer is present. In most cases, the specific type of cancer can be determined as well. But because cells from Ewing tumors share many of the same features as cells from other types of childhood cancer, more lab tests are often needed.

Immunohistochemistry

For this test, a portion of the sample is treated with special proteins (antibodies) that specifically attach to substances that are 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 tumor is in the Ewing family.

Cytogenetics

For this test, chromosomes (long strands of DNA) are looked at under a microscope to detect any changes. As noted in the section "Do we know what causes Ewing tumors?", cells from Ewing tumors usually have chromosome translocations, where 2 chromosomes swap pieces of their DNA. In most cases, Ewing tumor cells have translocations between chromosomes 11 and 22. Less often, the translocation is between chromosome 22 and another chromosome. Finding these changes can help distinguish Ewing tumors from other types of cancer.

Standard cytogenetic testing usually takes about 3 weeks because the cancer cells must grow in lab dishes for a couple of weeks before their chromosomes can be seen under the microscope. A newer form of cytogenetic testing is called fluorescence in situ hybridization (FISH). FISH uses special fluorescent dyes to recognize specific chromosome changes in Ewing tumors. FISH is very accurate and can usually provide results within a couple of days, which is why this test is now used in many medical centers.

Reverse transcription polymerase chain reaction (RT-PCR)

This test is another way to find translocations in the Ewing family of tumors cells to confirm the type of tumor. Instead of using a microscope to look for the chromosome changes as in cytogenetic testing, RT-PCR uses chemical analysis of the RNA (a substance related to DNA) from genes affected by the translocation. RT-PCR testing is often able to find translocations that aren't detected by cytogenetics.

RT-PCR is also useful in looking for left over or recurrent cancer after treatment. For example, if RT-PCR testing of a bone marrow sample after treatment finds a translocation, it is likely that the cancer has not been cured and more treatment may be needed.

Blood tests

There are no blood tests that can be used to diagnose the Ewing family of tumors. But certain blood tests may be helpful once a diagnosis has been made.

A complete blood count (CBC) can show abnormal levels of white blood cells, red blood cells, and platelets in the blood. An abnormal CBC result 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 has been linked with a larger amount of tumor in the body, which indicates the cancer may be harder to treat.

Blood tests can also be done to check a child's general health (especially before surgery) and to look for side effects during treatment such as chemotherapy. These tests may include complete blood counts and tests to measure how well the liver and kidneys are working.

Last Medical Review: 08/20/2009
Last Revised: 08/20/2009