Malignant Tumors


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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Of those who were exposed to radiation, 13, or 21.3%, were diagnosed with having a malignant tumor, while the figure for those who were not exposed to radiation was 35, or 15.3%.
Most of these benign and malignant tumors can be preoperatively diagnosed.
For example, convoluted cerebriform pattern is a reliable MRI feature of sinonasal inverted papillomas, [sup][8] but it is also demonstrated in a proportion of malignant tumors. Therefore, the discrimination between benign and malignant tumors on the basis of conventional CT and MRI findings is still difficult in a substantial number of cases, [sup][9],[10] and new imaging method is required to improve the discrimination.
However, among the malignant tumors, serous adenocarcinoma was most common and constituted 44.4% (12/27) of all ovarian malignancy.
Adenoid Cystic Carcinoma was the commonest malignant tumor (27 cases) which corresponded to 87% of the malignant tumors.
The malignant tumors of small intestine present with nonspecific clinical symptoms and inconclusive or incorrectly interpreted diagnostic tests.
After 29 weeks of exposure, CAsE-PE cells produced malignant tumors when inoculated into nude mice (Achanzar et al.
Differences in the numbers of these cell types between benign and malignant tumors were compared using the nonparametric Mann-Whitney statistical test.
(1) The smaller the gland has the higher the proportion of malignant tumors. The rate of malignancy in the parotid gland is 20-25%; it increases to 40-45% in the submandibular gland and to 51-80% in the sublingual and minor salivary glands.
1989); a third showed increased incidences of total malignant tumors, lymphomas and leukemias, and testicular interstitial-cell adenomas in male rats (Soffritti et al.
Although most tumors that originate in the external auditory canal are benign inflammatory polyps related to ear infections, a variety of other benign and malignant tumors occur there as well.