Sarcoma is named according to the type of tissue in which it begins to grow.
According to the American Cancer Society, about forty percent of cases occur in the legs, fifteen percent occur in the arms and hands, fifteen percent in the head and neck area, and thirty percent in the trunk. Sarcomas are not common but can be found in both adults and children. Researchers do not fully understand the cause of sarcomas. The first sign of a sarcoma may be a painless lump that grows and causes pressure against nearby nerves and muscles. Many such lumps are benign, not cancerous.