Soft tissue sarcomas occur with an incidence of 30 per million and represent less than 1% of all malignancies. They can occur in almost any anatomic site, but tend to occur with a frequency that reflects the volume of mesechymal-derived tissue in that region.  For example, around 55% occur in the limbs. The type of tumour varies with age: rhabdomyosarcoma is a disease of early life, whereas leiomyosarcoma is more common in the elderly.

Environmental factors associated with sarcoma include:

• Radiation (eg after therapeutic radiotherapy)
• Immunodeficiency
• Occupational (eg exposure to dioxins)

Genetic factors include