Rhabdomyosarcoma (RMS or ‘rhabdo’) is a tumor made up of cancerous cells that look like immature muscle cells.  In the United States, about 350 new cases are diagnosed each year in children under 15.  Almost two-thirds of children’s rhabdo cases develop in children under 10.

RMS may arise in any part of the body, but the most common sites for this tumor are:

• Adjacent to the base of the skull (parameningeal)
• Around the eye (orbital)
• Other superficial sites in the head and neck, such as the cheek or lip
• Arms and legs (extremities)
• Urinary system and reproductive sexual organs

In children, there are two major types of rhabdo, which are defined by how the tumor cells look under the microscope (pathology).

Embryonal rhabdomyosarcoma (ERMS) is the most common type.

• ERMS tends to occur in younger children.  Common sites include the area around the eye known as the orbit, around the head and neck, and the genitourinary system.
• ERMS often occurs in hollow organs that are lined with mucosa (moist tissue), such as the nasal passages, the vagina and the bladder, and can appear as a grape-like mass on the surface. 

Alveolar rhabdomyosarcoma (ARMS) makes up about 25-40% of RMS.  This type is more commonly found in adolescents and often occurs on the arms and legs.

Last updated July, 2011

Newly Diagnosed with Rhabdomyosarcoma
In Treatment for Rhabdomyosarcoma
After Treatment for Rhabdomyosarcoma