Biopsy and imaging. The most important test for diagnosing rhabdomyosarcoma (rms) is obtaining a biopsy of the mass and having a pathologist examine it. In general, there are three different types of rms alveolar, embryonal and pleomophic. Special stains will be used on the tissue, and other specialized tests (looking for specific chromosomal abnormalities) may be done. Body imaging will determine the staging.
CT and MRI. Depending on where this soft tissue malignancy is determines the more appropriate test. Both may be of benefit in the workup or follow up because they work on different physical principles when imaging the body's tissues and organs.