Ewing sarcoma
Ewing sarcoma is a cancer that occurs primarily in the bone or
soft tissue. It can occur in any bone, but is most often
found in the
extremities and can involve muscle and the soft tissues around the tumor
site. Ewing sarcoma cells can also spread (metastasize)
to other areas of the body
including the bone marrow, lungs, kidneys, heart, adrenal gland, and other soft tissues. It
accounts
for about 2 to 3 percent of childhood cancers.
About 150 children and adolescents are diagnosed with Ewing sarcoma each year
in the US. It is the second most common malignant bone tumor in children and
adolescents and accounts for about 30 percent of pediatric bone cancers.
Ewing sarcoma
most often occurs in children between
the ages of 10 and 20. Prior to adolescence, the number
of males
and females affected are equal. After adolescence, however, the number of males affected
is slightly higher than the
number of females. It has been suggested that the increased rate of growth
among males during adolescence may account for this increased
incidence
What
causes Ewing sarcoma?
The majority of Ewing
sarcomas result from a chromosome rearrangement between chromosomes #11 and #22.
This rearrangement changes the position and function of genes, causing a fusion
of genes referred to as a "fusion transcript." Over 90 percent of individuals
have an abnormal fusion transcript, involving two genes known as EWS and FLI1.
This important discovery has led to improvements in diagnosing Ewing
sarcoma.
Similar to osteogenic sarcoma, trauma or injury is sometimes involved with
the site at the time of diagnosis. However, this trauma is thought to bring the
condition to attention rather than to have any causal relationship.
Some physicians classify Ewing sarcoma as a primitive neuroectodermal tumor
(PNET). This means the tumor may have started in fetal, or embryonic, tissue
that has developed into nerve tissue.
The symptoms of Ewing sarcoma
The
following are the most common symptoms of Ewing sarcoma. However, each child may
experience symptoms differently. Symptoms may include, but are not limited, to
the following:
- Pain around the site of the tumor
- Swelling and/or redness around the site of the tumor
- Fever
- Weight loss, decreased appetite
- Fatigue
- Paralysis and/or incontinence (if the tumor is in the spinal region )
- Symptoms related to nerve compression from tumor (i.e., numbness,
tingling, paralysis, etc.)
The symptoms of Ewing sarcoma may resemble other conditions or medical
problems. Always consult your child's physician for a diagnosis.
Diagnosing Ewing sarcoma
In addition
to a complete medical history and physical examination of your child, diagnostic
procedures for Ewing sarcoma may include:
- Multiple imaging studies, such as:
- X-rays. A diagnostic test which uses invisible electromagnetic
energy beams to produce images of internal tissues, bones, and organs onto
film. this test is used to measure and evaluate the curve.
- Radionuclide bone scans. Pictures or x-rays taken of the bone after a dye has
been injected that is absorbed by bone tissue. These are used to detect
tumors and bone abnormalities.
- Magnetic resonance imaging (MRI). A diagnostic procedure that
uses a combination of large magnets, radiofrequencies, and a computer to
produce detailed images of organs and structures within the body. This test
is done to rule out any associated abnormalities of the spinal cord and
nerves.
- Computed tomography scan (also called a CT or CAT scan). A
diagnostic imaging procedure that uses a combination of x-rays and computer
technology to produce cross-sectional images (often called slices), both
horizontally and vertically, of the body. A CT scan shows detailed images of
any part of the body, including the bones, muscles, fat, and organs. CT
scans are more detailed than general x-rays.
- Blood tests (including blood chemistries)
- Biopsy of the tumor. A procedure in which tissue
samples are removed (with a needle or during surgery) from
the body for examination under a microscope; to determine if cancer or other
abnormal cells are present; to remove tissue from the affected
bone.
- Bone marrow aspiration and/or biopsy. A procedure
that involves a small amount of bone marrow fluid and tissue to be taken,
usually from part of the hip bones, to further examine the number, size, and
maturity of blood cells and/or abnormal cells; to detect cancer cells. Ewing
sarcoma is difficult to distinguish from other similar tumors. Diagnosis is
often made by excluding all other common solid tumors, and by the use of
genetic studies.