Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a rare type of soft tissue cancer that begins in cells that normally develop into skeletal muscle. Although it can occur at any age, RMS is most often diagnosed in children and teenagers. In the United States, roughly 350 to 400 pediatric cases are identified each year. Because RMS can arise almost anywhere in the body and tends to grow quickly, an early evaluation and specialized treatment are essential.

What are the causes and risk factors for rhabdomyosarcoma?

The exact cause of RMS is unknown, and most cases develop without any identifiable trigger. Researchers believe that a combination of genetic, developmental and environmental factors may play a role, although no single cause has been confirmed. Certain characteristics appear to increase the likelihood of developing RMS, including childhood age and several rare genetic or congenital conditions, including:

• Li-Fraumeni syndrome
• Neurofibromatosis type 1 (NF1)
• Beckwith-Wiedemann syndrome
• Costello syndrome
• Noonan syndrome
• DICER1 syndrome

These inherited syndromes may alter normal cell growth, increasing the likelihood that cancer could develop. Still, most patients have no known risk factors, and the condition often appears to arise sporadically.

Is rhabdomyosarcoma preventable?

There are no proven strategies to prevent RMS. Because a clear cause has not been established and most patients have no distinguishable risk factors, prevention is not currently possible. Awareness of unusual changes and a prompt evaluation of any persistent or unexplained masses can help support earlier detection.

What are the signs and symptoms of rhabdomyosarcoma?

RMS can occur in many different parts of the body, and its symptoms often resemble those of more common benign conditions. Some tumors cause few symptoms at first, while others produce noticeable changes as they grow.

What are the early warning signs of rhabdomyosarcoma?

Early symptoms of RMS often involve a new lump, mass or swelling that does not go away and may gradually increase in size. The lump may or may not be painful. Changes affecting nearby organs or structures can also serve as early warning signs, such as visual disturbances, difficulty passing urine or unexplained bleeding.

What are the most common symptoms of rhabdomyosarcoma?

RMS symptoms can vary widely based on the location of the tumor. Cancer that begins in the arms or legs may cause:

• Limb swelling or a noticeable lump under the skin
• Limited mobility or stiffness in the affected limb
• Localized pain, especially if the tumor is pressing on a nearby nerve
• Skin redness

If rhabdomyosarcoma develops in the head or neck area, symptoms can include:

• Swollen, bulging or crossed eyes
• Vision changes
• Sinus congestion
• Headaches
• Earaches
• Nosebleeds

RMS in the urinary or reproductive system may cause:

• Difficulty urinating
• Blood in the urine
• Rectal bleeding or unusual vaginal bleeding
• A mass that can be seen or felt in the genital area

Rhabdomyosarcoma that arises in the abdomen or pelvis may lead to:

• Abdominal pain
• Nausea and vomiting
• Constipation

What are the symptoms of advanced rhabdomyosarcoma?

As RMS progresses, the symptoms may become more severe or widespread. Advanced-stage cancer can cause:

• Significant pain or impaired function
• Rapidly enlarging masses
• Breathing problems, if RMS affects the lungs
• Bone pain, if the cancer spreads to the bones or bone marrow
• Fatigue, weight loss or decreased appetite

How is rhabdomyosarcoma diagnosed?

The diagnostic process for rhabdomyosarcoma usually involves a combination of medical history, physical examination, imaging studies and laboratory testing. Because RMS is rare and can mimic many other conditions, a thorough assessment by an experienced sarcoma specialist is often recommended.

What laboratory tests are used to diagnose rhabdomyosarcoma?

Blood work alone cannot confirm a diagnosis of RMS. However, several lab tests may be used to assess organ function, evaluate overall health and ensure the patient is ready for treatment. Common tests include a complete blood count (CBC) to measure blood cell levels and metabolic panels to check how well the liver and kidneys are functioning.

In some cases, specialized lab testing may also be performed to check for certain inherited genetic conditions associated with an increased risk of developing cancer. The results can help the physician plan treatment and identify other health concerns.

What imaging tests are used to diagnose rhabdomyosarcoma?

Imaging plays an important role in evaluating rhabdomyosarcoma because it can help the physician determine the tumor’s location, size and extent. Common imaging tests used during the diagnostic process include:

• Magnetic resonance imaging (MRI) for detailed soft tissue evaluation
• Computed tomography (CT) scans to assess deeper structures and check for possible cancer spread
• Ultrasound to examine surface-level or easily accessible masses
• Chest imaging to determine whether the tumor has spread to the lungs

Depending on the findings, the physician may recommend additional diagnostic studies, such as a bone scan or bone marrow evaluation, to determine whether the cancer has spread to other parts of the body.

What procedures are used to diagnose rhabdomyosarcoma?

A biopsy is required to confirm a diagnosis of RMS. Techniques may include:

• Core needle biopsy to collect a small sample of suspicious tissue
• Incisional or surgical biopsy to obtain tissue from a large or deep tumor

After the sample is collected, a pathologist will examine the tissue under a microscope for evidence of cancer. If rhabdomyosarcoma is identified, the pathologist may perform specialized lab tests to determine the cell type and subtype. This information can guide treatment planning and ensure an accurate diagnosis.

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How is rhabdomyosarcoma treated?

The optimal treatment approach for RMS depends on several key factors, including the tumor’s location, subtype and size and whether the cancer has spread to other parts of the body. These elements can help the physician determine which therapies are most appropriate and the order in which they should be delivered. Most patients are treated with a combination of therapies, such as surgery, chemotherapy and radiation therapy, coordinated by a multispecialty team. This collaborative approach ensures that each aspect of care is tailored to the patient’s individual needs and that all specialists involved are working together to achieve the best possible outcome.

How is surgery used to treat rhabdomyosarcoma?

Surgical treatment for RMS aims to remove as much of the tumor as possible while preserving nearby organs, nerves and normal function. When complete removal is feasible, surgery may serve as the initial treatment. In other cases, chemotherapy may be given first to shrink the tumor, making it easier and safer to remove with clear margins. Reducing the tumor size before surgery can also help protect critical structures and improve the likelihood of a successful outcome. Surgical planning is highly individualized, and the healthcare team will determine the most appropriate approach based on the tumor’s location, behavior and response to other treatments.

How is chemotherapy used to treat rhabdomyosarcoma?

A core component of RMS treatment, chemotherapy can target and destroy cancerous cells throughout the body. Because rhabdomyosarcoma can spread through the bloodstream, systemic therapy is often essential for addressing both the primary tumor and any microscopic cancer cells that may not yet be visible on imaging scans.

Chemotherapy may be used:

• Before surgery to shrink the tumor and improve the chance of a complete and safe removal
• After surgery to destroy any remaining cancer cells and reduce the risk of recurrence
• As the primary treatment, if the tumor cannot be surgically removed or has already spread to other parts of the body

The specific chemotherapy drug regimen will be tailored to the patient’s age, overall health and tumor characteristics. Treatment will be closely monitored so adjustments can be made as needed to achieve the best possible outcome.

How is radiation therapy used to treat rhabdomyosarcoma?

Radiation therapy may be used after surgery to destroy any remaining cancer cells that cannot be safely removed, helping to reduce the risk of local recurrence. In situations where surgery is not possible due to the tumor’s location or the patient’s overall health, radiation therapy may serve as the primary treatment to control tumor growth. It is also commonly used alongside chemotherapy, as combining these treatments can enhance their effectiveness.

Modern radiation delivery techniques facilitate the administration of carefully tailored doses that concentrate on the tumor while sparing as much surrounding healthy tissue as possible. This precise targeting can help limit side effects and support a safer, more effective treatment experience.

How is targeted therapy used to treat rhabdomyosarcoma?

Targeted therapy is not yet a standard treatment for RMS, but researchers continue to study its potential role as they learn more about the molecular changes that drive the growth of this rare and complex type of cancer. Targeted medications are designed to block the specific pathways or genetic alterations that help tumor cells survive and thrive, offering a more personalized approach to treatment.

Through ongoing research studies, scientists are evaluating targeted therapies for certain subtypes of rhabdomyosarcoma and advanced cancer that does not respond to conventional treatments. Many of these novel approaches are available only through clinical trials, which allow participants to access promising new medications while helping researchers better understand how these therapies may benefit those with RMS.

How is immunotherapy used to treat rhabdomyosarcoma?

Immunotherapy is not yet routinely used for RMS, but some patients may be eligible for clinical trials evaluating immune-based treatment strategies. These therapies aim to stimulate or enhance the body’s natural defenses so the immune system can better recognize and attack cancer cells. Researchers are currently studying several approaches, including checkpoint inhibitors and other agents designed to overcome the mechanisms RMS cells use to avoid detection by the immune system.

Ongoing research is helping scientists and clinicians better understand how the immune system interacts with RMS and which patients may benefit most from these emerging treatments. As knowledge evolves, immunotherapy may play a more prominent role in the future care of patients with this rare cancer.

Are there other treatment options for rhabdomyosarcoma?

A clinical trial may be an option for a patient who has advanced or recurrent RMS or is seeking alternatives to traditional treatments. Participation in a research study may allow the patient to benefit from a promising new therapy while contributing to advancements in cancer care.

In addition to active cancer treatment, supportive services may play an important role throughout the patient’s journey. Rehabilitation, nutritional counseling and symptom management can help preserve strength, reduce side effects and support overall quality of life both during and after treatment. These resources are valuable complements to clinical care and can be tailored to meet the patient’s individual needs.

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If you have questions about rhabdomyosarcoma, you can request an appointment with a specialist in the world-renowned Sarcoma Program at Moffitt by calling 1-888-663-3488 or completing our new patient registration form online. We do not require referrals.