metastasis

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metastasis

1. Pathol the spreading of a disease, esp cancer cells, from one part of the body to another
2. a rare word for metabolism
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Metastasis

 

a secondary pathological focus arising from the transfer of a pathogenic principle (tumor cells, infectious agent) from the primary site of affection by the lymph or blood.

In the modern view, the term “metastasis” generally applies to the spread (dissemination) of malignant tumor cells; the spread of an infectious principle is usually described by the term “metastatic infectious focus.”

Benign tumors are also known to metastasize, and the capacity to do so is inherent in normal cells of various origin (in placental villi, adipose and hematopoietic bone-marrow cells). A distinctive feature of metastasizing tumor cells is the uncontrollable growth of the metastasis, relating it to primary foci of malignant growth. Metastatic tumor nodes retain other properties of primary tumors as well, such as microstructural features and the capacity to form the same products; however, metastatic nodes often have a more primitive structure and consist of functionally less mature cells than do the original tumors.

When tumor cells spread chiefly through the lymphatic vessels, metastases generally appear in the lymph nodes closest to the primary site. Although much research has been devoted to the routes and anatomical patterns of lymphogenous metastasis, the biological patterns of formation of lymphogenous metastases remain obscure. The mechanisms of hematogenous metastasis (to the lungs, liver, bones, and other viscera) are better understood. Four stages in the development of hematogenous metastasis are distinguished: (1) the detachment of cells from the primary tumor node and their penetration of the blood through the vascular wall; (2) the circulation of the tumor cells in the blood; (3) the attachment of the cells to the vascular wall and the start of intravascular growth; and (4) the rupture of the vascular wall by the tumorous masses and the subsequent growth of the metastasis into the tissue of the affected organ. The presence of metastasis indicates that a tumorous process has shifted from a local growth phase to a phase of generalization. A distinction is made between solitary metastasis, which generally can be removed surgically, and multiple metastases, which require combined treatment using radiation and chemotherapy.

N. S. KISELEVA

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

metastasis

[mə′tas·tə·səs]
(medicine)
Transfer of the causal agent (cell or microorganism) of a disease from a primary focus to a distant one through the blood or lymphatic vessels.
(physics)
A transition of an electron or nucleon from one bound state to another in an atom or molecule, or the capture of an electron by a nucleus.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Molecular assignment of tissue of origin in cancer of unknown primary may not predict response to therapy or outcome: a systematic literature review.
(3) To our knowledge, there are few reported cases of cancer of unknown primary site that were found to have metastasized to the cutaneous-subcutaneous anterior abdominal wall and no cases presenting as an isolated intramuscular abdominal wall mass.
The common differential diagnoses include metastases of malignancies primary to the head and neck, malignant lymphoma, and cancer of unknown primary site (CUP).
Aileen Orr, 50, is tackling the Simplyhealth Great Women's Run to highlight Cancer of Unknown Primary (CUP).
Deaths from Cancer of Unknown Primary are about eight per cent of all cancer deaths.
There are plenty of published data proving that miRNAs are better markers in some instances than proteins or mRNA (identifying cancer of unknown primary is only 1 important example).