The first sign of Ewing sarcoma may be pain in a bone or joint. The individual may think the pain and swelling comes from a sports injury or sprain. However, a doctor should evaluate the symptoms when pain does not go away in a reasonable amount of time.
Evaluation of the patient begins with imaging studies, such as X-ray, computed tomography (CT) scan, or magnetic resonance imaging (MRI), to locate the suspected tumor. Other imaging techniques that may be used include a chest CT, a bone scan and positron emission tomography (PET) scan. These images are helpful in evaluating the lungs and bones, areas to which the cancer commonly spreads (metastasizes).
To diagnose Ewing's sarcoma, the doctor removes small samples of the suspected tumor for examination (biopsy). A pathologist looks at the cells under a microscope to determine whether the tissue contains malignant cells. In some cases, tumor cells are tested for chromosome abnormalities.
A bone marrow biopsy may also be needed to help doctors determine the extent of the disease.