sarcoma

a malignant tumor that consists of connective tissue. Mesenchymomas, which are sarcomas made up of embryonic connective tissue (mesenchyma), are distinguished from sarcomas made up of mature tissues of mesenchymal origin, for example, bone sarcomas (osteosarcomas), cartilaginous sarcomas (chondrosarcomas), vascular sarcomas (angiosarcomas), hematopoietic sarcomas (reticulosarcomas), muscular sarcomas (leiomyosarcomas, rhabdosarcomas), and sarcomas of skeletal nerve tissue (gliosarcomas).

Sarcomas constitute about 10 percent of all malignant tumors; they occur relatively more often in some African and Asian countries. The most common sarcomas are bone tumors and tumors of soft tissues, including muscular, vascular, and nerve tissues. Sarcomas of the hematopoietic organs occur less frequently. Histomorphologically, there are round-cell, polymorphocellular (sometimes giant-cell), and spindle-cell sarcomas, all of which differ in the shape and size of the cells, and fibrosarcomas, in which fibrous elements predominate over cellular elements.

All malignant tumors are characterized by growing into and destroying surrounding tissues; this property is especially pronounced in sarcomas. The early stages of cancers differ from the early stages of sarcomas; cancers metastasize to the nearest lymph nodes, while sarcomas usually spread by way of the bloodstream and frequently metastasize to remote organs.

The principles and methods of diagnosis, preventive measures, and treatment of sarcomas are the same as those used for other malignant tumors.