Sarcoma

Sarcoma is an ancient term which was vaguely used of tumours of a more or less flesh-like consistency, but had fallen into disuse. It was adopted by Virchow as the general name for a large and important class of new formations, and is at present universally employed as defined by him. The tumours now called Sarcomata are mainly composed of cells resembling those of some form of embryonic or imperfectly developed connective tissue, rather than those of any part of the adult organism. Their structure, as well as their individual cells, usually suggests an embryonic condition: the cells are imbedded in a structureless matrix; and the blood-vessels are often mere channels between the tumour-cells. They are thus distinct from the Carcinomata, or cancers proper, which consist of epithelial cells in a framework of fully organised fibrous tissues; though they share with them the property of malignancy (see TUMOURS). They are generally classified, according to the form of their most characteristic cells, as round-celled, spindle-celled, and myeloid sarcomata. They are most common before middle life, and may occur in any organ of the body. Their course presents the greatest possible variety: some myeloid and spindle-celled sarcomata are slow in their growth, and but little apt to recur after removal: some forms of round-celled sarcoma may rival and even surpass the true cancers in rapidity of growth and diffusion through the body. When secondary tumours occur they are not commonly in the neighbouring lymphatic glands, as in cancer, but in distant organs, and particularly in the lungs.