Ewing Sarcoma Treatment (PDQ®): Treatment - Patient Information [NCI] - General Information About Ewing Sarcoma
A biopsy is done to diagnose Ewing sarcoma.
Tissue samples are removed during an incisional or needle biopsy so they can be viewed under a microscope by a pathologist to check for signs of cancer. It is helpful if the biopsy is done at the same center where treatment will be given.
- Needle biopsy: For a needle biopsy, tissue is removed using a needle. This type of needle biopsy may be done if it's possible to remove tissue samples large enough to be used for testing.
- Incisional biopsy: For an incisional biopsy, a sample of tissue is removed through an incision in the skin.
- Excisional biopsy: The removal of an entire lump or area of tissue that doesn't look normal.
For an incisional or excisional biopsy, the specialists (pathologist, radiation oncologist, and surgeon) who will treat the patient usually work together to decide where the incision should be made. This is done so that the biopsy incision doesn't affect later treatment such as surgery to remove the tumor or radiation therapy.
If there is a chance that the cancer has spread to nearby lymph nodes, one or more lymph nodes may be removed and checked for signs of cancer.
The following tests may be done on the tissue that is removed:
- Cytogeneticanalysis: A laboratory test in which cells in a sample of tissue are viewed under a microscope to look for certain changes in the chromosomes.
- Immunohistochemistry: A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer.
- Flow cytometry: A laboratory test that measures the number of cells in a sample, the percentage of live cells in a sample, and certain characteristics of cells, such as size, shape, and the presence of tumor markers on the cell surface. The cells are stained with a light-sensitive dye, placed in a fluid, and passed in a stream before a laser or other type of light. The measurements are based on how the light-sensitive dye reacts to the light.