TUMOR

a swelling caused by some form of new growth. Tumors fall into three groups—connective ti ue tumors, epithelial tumors, and dermoid tumors. (1) Connective Ti ue Tumors. — The great majority of these are of an innocent type, and their structure corresponds with that of the ti ues in which they arise. They are usually encapsulated. As a rule, they grow slowly, and generally give rise to danger only by pre ure upon important structures. All connective ti ue tumors which exhibit malignancy are sarcomatous. Sarcomata grow rapidly, and having no capsule invade neighboring ti ues and organs. Their infiltration of blood-ve els leads to di emination and to the production of secondary growths by the distribution of sarcoma cells to distant parts of the body. Their growth from small fragments explains their recurrence after incomplete removal. Of sarcomata three varieties are described. (i) Round-celled sarcomata are composed of ma es of round cells like those of granulation ti ue. Such tumors grow rapidly, and are extremely malignant. (ii) Spindle-celled sarcomata grow more slowly, and approach more nearly to the structure of fibrous ti ue. They are le malignant than the round celled variety. (iii) Melanotic or pigmented sarcomata are extremely malignant, and of rapid growth. The cell elements are usually spindle-shaped. (2) Epithelial tumors contain epithelium as the e ential and characteristic feature. When simple they are either papillomatous (7.e.), of a warty nature— or adenomatous—that is, glandular. Warts, although non-malignant, may endanger life; in the larynx they may cause suffocation; in the bladder they may produce fatal anemia from continued hemorrhage; while pigmented warts frequently a ume malignant characters. Adenomata arise from the epithelium of secreting glands, and often become cystic from the accumulation of perverted secretion. They have no tendency to recur, do_not give rise to secondary deposits, and do not infect neighboring lymph glands, but may endanger life from their size and from pre ure upon Vital organs. Malignant epithelial tumors are carcinomata See CANCER. (3) Dermoid tumors contain skin or mucous membrane with cutaneous appendages, such as hair or teeth, and occur in situations where these structures are not found normally. With the exception of the Ovarian variety, dermoid cysts are congenital. They are jnnocent; but moles sometimes a ume malignant characters, and ovarian dermoids are dangerous to life in a variety of ways. Teratomata are sometimes confounded with dermoid cysts; but as they contain imperfect ti ues of a suppre ed. but separate foetus attached to an otherwise normal individual, they must be cla ed with monstrosities rather than with tumors. Phantom tumor is a hysterical affection which often simulates pregnancy.