A usually aggressive malignant mesenchymal cell tumor most commonly arising from muscle, fat, fibrous tissue, bone, cartilage, and blood vessels. Sarcomas occur in both children and adults. The prognosis depends largely on the degree of differentiation (grade) of the tumor. Representative subtypes are liposarcoma, leiomyosarcoma, osteosarcoma, and chondrosarcoma. -- 2004
