Overview
Rhabdomyosarcoma (rab-doe-my-oh-sahr-KOE-muh) is a rare cancer that starts as a growth of cells in soft tissue. Rhabdomyosarcoma is a type of soft tissue sarcoma. Soft tissues connect, support and surround other structures in the body. Soft tissues include muscle, fat, blood vessels, nerves, tendons and the linings of the joints.
Rhabdomyosarcoma is the most common soft tissue sarcoma in children. But teenagers and adults can get it too.
Rhabdomyosarcoma can start almost anywhere in the body. It often starts in the:
- Head and neck.
- Urinary system, such as the bladder.
- Reproductive system, such as the vagina, uterus and testes.
- Arms and legs.
The prognosis, also called the outlook, is different from person to person. It generally is better when the cancer has not spread far from where it started. Age, where the tumor starts, tumor size and whether there are specific gene changes in the cancer cells also affect the outlook. Rhabdomyosarcoma in children differs from rhabdomyosarcoma in adults in the types that are more common and in the overall outlook. Children generally have a better outlook than adults do.
Types
Rhabdomyosarcoma has four main types. The type is based on how the cancer cells look under a microscope and whether the cancer has specific gene changes. These differences can affect the treatment plan.
- Embryonal rhabdomyosarcoma is the most common type in children. It often starts in the head and neck or the urinary or reproductive systems. Its cells can vary in how they look. Some look more like mature muscle cells. Others look like very immature cells and not yet like muscle cells.
- Alveolar rhabdomyosarcoma is different from embryonal rhabdomyosarcoma in a number of ways. It's more common in older children, teenagers and adults than in young children. And it often starts in the arms, legs or trunk instead of the head and neck. Alveolar rhabdomyosarcoma gets its name because its cells often grow in groups separated by bands of tissue. This makes a pattern that can look like the tiny air sacs in the lungs, called alveoli. Many alveolar rhabdomyosarcomas also have a gene change called a FOXO1 fusion. This gene change can help diagnose alveolar rhabdomyosarcoma and affect the outlook.
- Spindle cell-sclerosing rhabdomyosarcoma is not a common type of rhabdomyosarcoma. It may start in the head, neck, arms, legs or trunk. This type can happen in infants and tends to have a good outlook when it does. This type also can happen in teenagers or adults and may act aggressively. The cells in spindle cell-sclerosing rhabdomyosarcoma may be long and narrow, also called spindle shaped. Some tumors may have dense, scarlike tissue in them.
- Pleomorphic rhabdomyosarcoma is a rare type that mostly affects adults, especially older adults. It often starts in the arms or legs. It also can start in the trunk. The term pleomorphic means that the cancer cells can look very different from one another in shape and size. This type tends to be aggressive and harder to treat. The treatment approach for pleomorphic rhabdomyosarcoma may be different from the approach for other types of rhabdomyosarcoma.
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Symptoms
Signs and symptoms of rhabdomyosarcoma can differ depending on where the cancer starts and how large the tumor grows.
General symptoms
As a rhabdomyosarcoma grows, it may cause:
- A noticeable lump or swelling.
- Pain.
You can't tell whether a lump is a sarcoma simply by how it looks or feels.
Head and neck
Symptoms may include:
- Bleeding from the nose, throat, ears or eyes.
- Changes in vision.
- Eye that bulges.
- Stuffy nose.
- Earache.
- Headache.
Urinary or reproductive systems
Symptoms may include:
- Bleeding from the vagina.
- Blood in the urine.
- Needing to urinate more often.
- Trouble urinating.
- Constipation.
Arms and legs
Symptoms may include:
- Arm or leg pain.
- Arm or leg weakness.
- One arm or leg area that looks bigger than the same area in the other arm or leg. This may even cause clothing to feel tighter in that area.
Belly or pelvis
Symptoms may include:
- Constipation.
- Swelling of the belly.
- Vomiting.
When to seek care
Many signs and symptoms of rhabdomyosarcoma are usually caused by something else. Still, make an appointment with a healthcare professional for:
- A lump, swelling or other symptom that does not go away or gets worse.
Also, have a lump checked if it:
- Continues to grow.
- Is larger than about 2 inches (5 centimeters).
- Feels like it is deep beneath the skin.
Do not wait for a lump to become painful before seeing a healthcare professional. A soft tissue sarcoma lump may not hurt.
Causes
It's not clear what causes rhabdomyosarcoma. It starts when a soft tissue cell develops changes in its DNA. A cell's DNA holds the instructions that tell a cell what to do.
In healthy cells, the DNA gives instructions that help control when cells grow, multiply and die. In cancer cells, DNA changes give different instructions. The changes can tell the cancer cells to grow and divide when they should not or to keep living when healthy cells would die. This causes too many cells to build up.
The cancer cells might form a mass called a tumor. The tumor can grow into and destroy healthy tissue. In time, cancer cells can break away and spread to other parts of the body. When cancer spreads, it's called metastatic cancer.
Some types of rhabdomyosarcoma have specific gene changes in the cancer cells. These changes can help identify the type of rhabdomyosarcoma and may help guide treatment decisions. But for most people with rhabdomyosarcoma, there is no known cause or inherited condition that explains why the cancer happened.
Risk factors
Most people with rhabdomyosarcoma do not have a known risk factor.
Factors that may increase the risk include:
- Younger age. Rhabdomyosarcoma happens most often in children and teenagers.
- Inherited cancer syndromes. Some cancer syndromes passed down through families can increase the risk of rhabdomyosarcoma. These include Li-Fraumeni syndrome, neurofibromatosis type 1, Costello syndrome, Noonan syndrome, Beckwith-Wiedemann syndrome and DICER1 syndrome.
Sept. 18, 2026