What is Alveolar Rhabdomyosarcoma (ARMS)?
Also known as...
- Alveolar rhabdomyosarcoma of soft tissue
- ARMS
- Alveolar RMS
- Alveolar type
Alveolar rhabdomyosarcoma is a type of sarcoma that affects the muscles and is more commonly found in children and adolescents. It is a rare and aggressive form of rhabdomyosarcoma that typically arises in the large skeletal muscles, especially the arms and legs.. The skeletal muscles are the ones used for conscious movement.
The name “alveolar” comes from the appearance of the tumour cells under the microscope, which resemble the small air sacs (alveoli) in the lungs. The tumour cells tend to grow in clusters, which can make it difficult to remove them completely with surgery.
How rare is it and who does it affect?
Alveolar rhabdomyosarcoma is a very rare type of cancer, accounting for about 1% of all childhood cancers. In the UK, it is estimated that there are around 30 new cases of rhabdomyosarcoma diagnosed each year, and of these cases, approximately 20-25% are classified as the alveolar subtype, approximately 0.01 cases per 100,000.
The exact cause of alveolar rhabdomyosarcoma is not known, but certain risk factors may increase the likelihood of developing the disease. These include exposure to radiation, certain genetic syndromes (such as Li-Fraumeni syndrome), and a family history of cancer. However, most cases of alveolar rhabdomyosarcoma occur in people with no known risk factors.
Alveolar rhabdomyosarcoma tends to occur more frequently in children and adolescents than in adults. It is most commonly diagnosed in children between the ages of 10 and 14 years old, although it can occur in younger children and adults as well.
It may occur slightly more often in boys and children with African ancestry.




















