Diagnosing Rhabdomyosarcoma

Pictured: Leonard Wexler & Joanna Moulton

A proper diagnosis leads to proper treatment. When our doctors suspect that a child, teen, or young adult has rhabdomyosarcoma, they take a sample of the affected tissue. This typically involves removing a small part of the tumor while the patient is under anesthesia. The doctor sometimes takes out the entire tumor during this process.

Our pathologists test the tissue to look for specific signs of this disease. For example, one test can identify a genetic abnormality found only in alveolar rhabdomyosarcoma. Researchers at MSK were the first to identify a different mutation in some patients with the embryonal form of rhabdomyosarcoma. We do genomic profiling on all newly diagnosed patients with rhabdomyosarcoma.

After doctors make a diagnosis, they use the information they collected to determine the stage (extent) of the tumor. This shows how advanced the cancer is, and if and where it has spread. Because rhabdomyosarcoma can spread throughout the body, our experts may also do bone marrow tests and imaging studies such as MRI, CT scans, PET scans, and bone scans to find out how far the tumor has spread.

These tests allow MSK doctors to put children and young adults with rhabdomyosarcoma into different risk groups — low, intermediate, or high — based on how much of the body is involved and how they expect the patient to respond to treatment.

For rhabdomyosarcoma, the staging system is based on the primary site of the tumor, the size of the tumor, whether the tumor has spread, the way the tumor looks under the microscope, and the extent of surgery at the time of diagnosis.

The stages of rhabdomyosarcoma are:

Stage I: The tumor can be any size and may have spread to nearby lymph nodes, but nowhere else in the body. The tumor started in a favorable area such as:

  • the area surrounding the eye
  • the head and neck region, except for the nasal passages, sinuses, middle ear, or upper throat (these are next to the membranes that cover the brain)
  • a genital or urinary site, except the prostate or bladder
  • bile ducts

Stage II: The tumor is five centimeters or smaller and has not spread anywhere else in the body. However, the tumor started in an unfavorable area such as:

  • the nasal passages, sinuses, middle ear, or upper throat
  • the bladder or prostate
  • an arm or a leg
  • somewhere in the body not mentioned in stage I

Stage III: The tumor is five centimeters or smaller but has spread to nearby lymph nodes. Or, the tumor is larger than five centimeters and may or may not have spread to lymph nodes. The tumor has not spread elsewhere.

Stage IV: The tumor can start anywhere and be any size; it has spread to distant areas like the lungs, liver, or bone marrow.