Alveolar rhabdomyosarcoma | Sarcoma UK
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Alveolar rhabdomyosarcoma

Alveolar rhabdomyosarcoma, also known as “ARMS”, is a type of soft tissue sarcoma. It develops from the cells in skeletal muscle, and often in teenagers and young adults.

ARMS can occur anywhere in the body, but it often occurs in the arms and legs. It can also occur in:

  • the head and neck area
  • the muscles around the spine
  • the area between the genitals and the anus.
ARMS is mostly associated with people between the ages of 10 and 25 years old. ARMS doesn’t occur more in either sex.


There are an average of 31 cases of ARMS diagnosed every year in England.

ARMS makes up just over a quarter of all rhabdomyosarcoma diagnoses.

For more information on these statistics, you can visit our soft tissue sarcoma data hub.

Signs and symptoms

Symptoms of ARMS can vary depending on the size and location of your tumour.

The main symptom of ARMS is a lump, lesion or swelling in the soft tissue of the body under the skin. It often appears in the arms and legs. It’s often fast-growing, but usually painless.
A lesion in the head or neck can result in symptoms such as:
  • Loss of hearing or balance
  • Bulging of the eyes
  • Weakness, numbness, or pain in the face
  • Trouble swallowing

A lesion in the muscles around the spine can result in symptoms such as:

  • Back pain
  • Difficulty walking
  • Loss of bowel or bladder control

A lesion in the area between the genitals and the anus can result in symptoms such as:

  • Constipation
  • Abdominal pain, swelling, or bloating
  • Blood in the pee or poo


A specialist doctor will diagnose ARMS through a series of tests. These may include:
  • Physical examination – looking at and feeling any lump.
  • A scan – taking pictures of the inside of the body using scans such as CT, MRI, PET, x-ray, or ultrasound scans.
  • A biopsy – taking and testing a sample of the tumour. Using this biopsy, a doctor will look to see if the biopsy looks like ARMS. They will also look to see whether it contains the chromosome error.
  • A lumbar puncture – ARMS sometimes starts in the muscles around the spine, and can spread or grow to the spine. A lumbar puncture uses a small needle to take a sample of the fluid that surrounds the spine. It does this to look for any cancer cells.
  • Bone scans and bone marrow biopsies – ARMS sometimes spreads to the bone marrow. Bone scans and bone marrow biopsies can test for this.
To read more about these scans and tests, click here.


  • Surgery
    • The first treatment method for ARMS is surgery. The surgeon will remove the tumour and will aim to take out an area of normal tissue too. This is known as “taking a margin”. This is to make sure that all the cancer has been removed.
    • ARMS mostly affects the arms and legs. Surgeons will do limb-sparing surgery so that the limb can continue to work well.
    • Very rarely, the cancer can spread throughout the limb. In this case, the surgeon may have to perform a partial or full amputation to stop the cancer.
  • Radiotherapy
    • This treatment uses high-energy radiation to destroy cancer cells.
    • It can be used either before or after surgery.
      • When used before surgery, radiotherapy aims to make the tumour smaller. This is so that it can be more easily removed.
      • When used after surgery, radiotherapy aims to kill off any remaining cancer cells that were not removed by surgery.
  • Chemotherapy
    • This treatment uses anti-cancer drugs to destroy cancer cells. It’s sometimes used in patients that have a high risk of the cancer coming back. It’s also sometimes used if the cancer has spread to other parts of the body, also known as “metastasis”.
  • Targeted and experimental therapies
    • Researchers have been learning more about treatments known as “targeted therapies” and “immunotherapies”.
      • Targeted therapy is a treatment that targets specific characteristics within cancer cells. It does this to stop them from growing and spreading.
      • Immunotherapy is a treatment that helps a person’s immune system fight and kill cancer cells.
    • Some targeted therapies and immunotherapies have worked well in clinical trials of ARMS. We need more research and trials before these treatments can be approved.
  • Clinical trials
    • Your doctor may offer you an opportunity to take part in a trial. The trial might investigate new diagnosis methods, drugs, or treatments. Some studies also look at the care and well-being of patients. Your doctor or nurse can give you more information on taking part in a clinical trial.
    • There are trials currently recruiting patients with ARMS. For more information, please follow this link.

After treatment

After treatment, you will have regular follow-up appointments for several years. You should receive a follow-up schedule from your sarcoma clinical nurse specialist. The follow-ups will usually include:

  • A chance to discuss symptoms.
  • An examination to look for any signs of ARMS returning. This may include scans such as CT or MRI scans.
  • A chest x-ray and bone scans to rule out any secondary cancers occurring in the lungs or bone marrow.

Living with

ARMS can reappear in the same area after the treatment of a previous tumour. This is called a “local recurrence”.
If the cancer does reappear, it is important to get treated as quickly as possible. This could involve further surgery and/or radiotherapy. Your doctor will assess your treatment plan on an individual basis. It’s also useful to check for recurrences yourself through self-examination. Your doctor can tell you what to look for.
If you’re worried about your cancer returning, please contact your doctor or nurse. They may prioritise your follow-up appointment so they can investigate your concerns.
What if my cancer spreads to another part of my body?
A recurrence of ARMS may be accompanied by cancer in other parts of the body. This is called “metastasis” or “secondary cancer”. Some people are diagnosed with sarcoma because their secondary cancer is discovered before their primary cancer. In ARMS patients, these secondary cancers can appear in the lungs. This is why you will have a chest x-ray at follow-up appointments.
Secondary cancers may also appear in the bone marrow and lymph nodes. Treatment for secondary cancer may involve surgery, radiotherapy or other treatment as appropriate. Your doctor will assess your treatment plan on an individual basis.

If you have any questions or if you need to talk to someone, our Support Line team are here for you.


More information –

An overview of ARMS

Last reviewed: 6 March 2023

Next review due: 6 March 2026


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