Rhabdomyosarcoma

Rhabdomyosarcoma (Greek: rhabdos ∈= ∈rod, myos ∈= ∈muscle, sarkos ∈= ∈flesh) is a primary malignancy in children and adolescents that arises from embryonic mesenchyme with the potential to differentiate into skeletal muscle. Rhabdomyosarcoma accounts for over half of all soft tissue sarcomas in children and, with approximately 250-300 new cases per year in the United States, the third most common solid tumor in infants and children behind neuroblastoma and Wilms tumor. In adults, rhabdomyosarcomas arise mostly in the extremities, while in children they can occur in any anatomical location of the body, even in places where there is no skeletal muscle, such as the urinary bladder or biliary tree. In fact, the disease can arise at any site and in any tissue in the body except bone. The most common sites are the head and neck region and the genitourinary tract, with only 20% occurring in the extremities.