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1. Pathol the spreading of a disease, esp cancer cells, from one part of the body to another
2. a rare word for metabolism



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.



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.
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.
References in periodicals archive ?
Diagnosis of metastases to the breast can be confirmed using comparative histopathology of the mammary lesion and the primary cancer.
7 Zacet et al, reported results of 20-years experience of surgical management of brain metastases from melanoma and concluded that surgical resection along with WBRT improved survival and quality of life in these patients.
On examination, choroidal metastases appear as pale subretinal lesions.
During the follow-up, 21 patients developed distant metastases, 56 developed intrahepatic recurrences, and 15 developed both.
Cyclin Dl overexpression and p27 underexpression were found in a variety of tumors and were associated with increased tumor aggressiveness, incidence of lymph node metastases, and poorer prognosis (13).
Brain metastases cause an estimated 20% of all cancer deaths in the United States annually.
In fact, bone metastases lead to an increased risk of morbidity and death in patients with CRPC.
Contrast enhanced MRI is more sensitive scanning in detecting brain metastases, especially small lesions or metastases situated in the posterior fossa.
For each patient, we collected information on baseline characteristics, such as age, sex, date of nephrectomy, prognostic class based on the Heng criteria, (14) and site of metastases at the beginning of the third-line treatment.
3%[5] The detection of skin metastases in lung cancer signifies end-stage disease and confers a poor prognosis.
In clinically node negative neck, lymph nodes in the neck are also treated with surgery or radiotherapy because statistical data from various studies reveal that the risk of occult cervical lymph node metastases in such cases ranges from 20% to 40%4 although in majority of the cases this aggressive treatment is totally unnecessary.
Cardiac metastases can also occur in the absence of hepatic metastases as noted in 4 case reports, though only one originated from the small bowel.