Malignant Tumors


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Malignant Tumors

 

growths of cells that have lost their normal properties and communication with the body and have the capacity, while invading surrounding tissues, to disrupt them and produce metastases—that is, to transport themselves into other organs and tissues and form secondary tumor foci.

Malignant tumors include sarcomas, malignant tumors of connective tissue; cancer, malignant tumors that develop from epithelial tissue; and some forms of leukoses. They are found in man and animals. With the rise in average longevity in countries where medicine is highly developed, malignant tumors are diagnosed in more cases; they are the second greatest cause of death (after cardiovascular diseases).

External causes of malignant tumors may be certain radiations and chemical substances (carcinogenic substances); internal causes may be disturbances of metabolism and hormone balance. A number of tumors in animals are caused by viruses.

Treatment of malignant tumors includes surgery, radiation, and medication (and their combinations). Prophylaxis calls for decreasing the level of harmful influences on the body and the timely discovery and cure of so-called precancerous or preneoplasmic changes and early forms of malignant tumors.

L. M. SHABAD

References in periodicals archive ?
A higher median age of 60-65 years for malignant tumors has been reported from India and the western countries12,13.
Malignant tumors of the orbit may originate either from the primary orbital tissues including the eyeball, or may invade from surrounding structures like eyelids, paranasal sinuses, nasopharynx or cranial cavity.
There is no confirm clinical criteria for differentiation of benign and malignant tumors.
The incidences of bilateral neoplasm are more frequently seen in malignant tumors.
Adenoid Cystic Carcinoma was the commonest malignant tumor (27 cases) which corresponded to 87% of the malignant tumors.
Comparison of the information on for the first time revealed cases malignant tumors between the State register and the Cancer -register is quarterly carried out.
On May 12, 1999, Gipson, then 40, was seen at High Desert for examination of an abnormal mass on a portion of her right lung, which medical personnel suspected was either a malignant tumor or the result of an infection, wrote Principal Deputy County Counsel Gary N.
They compared the results with studies conducted on 235 people who were born in the same period and were also suspected of having malignant tumors but were not exposed to radiation, the officials said.
There was significant difference in age, hypertension, occupation type, malignant tumors, operation time, smoking status, and postoperative exercises between the two groups (p0.
1) The smaller the gland has the higher the proportion of malignant tumors.
Methods: This retrospective study included 197 consecutive patients with sinonasal tumors (116 malignant tumors and 81 benign tumors).
The arsenic-transformed cells had been exposed continuously to sodium arsenite and, after 29 weeks of exposure, produced malignant tumors when inoculated into nude mice.