by Jason Wasserman MD PhD FRCPC
September 25, 2024
Rhabdomyosarcoma is a type of cancer that develops from skeletal muscle tissue, the muscle responsible for voluntary movements like walking or lifting objects. This cancer most commonly affects children, but it can also be found in adults. Rhabdomyosarcoma can occur almost anywhere in the body, but it most frequently arises in areas such as the head and neck, arms, legs, or the urinary and reproductive organs. It is considered an aggressive cancer, meaning it has the potential to grow and spread quickly if not treated.
The symptoms of rhabdomyosarcoma depend on where the tumour is located. Common symptoms include:
The exact cause of rhabdomyosarcoma is not fully understood. In most cases, no specific risk factors are identified. However, certain genetic conditions, such as Li-Fraumeni syndrome or neurofibromatosis, increase the risk of developing rhabdomyosarcoma. In many cases, rhabdomyosarcoma develops without any known cause.
In some types of rhabdomyosarcoma, specific genetic changes are known to play a role in the development of the tumour. For example, alveolar rhabdomyosarcoma is often associated with a specific genetic fusion, where two genes (PAX3 or PAX7 and FOXO1) become joined together abnormally. This genetic change drives the growth of cancerous cells. Other types of rhabdomyosarcoma may have different genetic mutations, but not all cases have identifiable genetic abnormalities.
There are several types of rhabdomyosarcoma, each with unique features:
The diagnosis of rhabdomyosarcoma is made through a combination of clinical evaluation, imaging studies (such as MRI or CT scans), and a tumour biopsy. A biopsy involves removing a small tissue sample from the tumour, which a pathologist examines under a microscope. The pathologist looks for specific features that help distinguish rhabdomyosarcoma from other types of cancer.
To confirm the diagnosis of rhabdomyosarcoma and determine its specific type, pathologists use several tests: