A metastasis is a migrated malignancy. A metastatic neoplasm — also known as a metastatic tumor — is a cancerous tumor whose cells have migrated from a primary site of cancer to a secondary site. As a diagnosis, metastatic neoplasm is a form of secondary cancer. A metastatic neoplasm is made up of abnormal cell growths from an adjoining organ, or tumor cells that have invaded the second site’s organs after traveling through either the blood or lymph networks. Sometimes it takes a considerable battery of tests to discover the primary site of the cancer.
The primary site is the site in the human body where cancer first developed. The cells of a metastatic neoplasm can be examined carefully for clues as to the makeup of the first cells, sometimes leading to the discovery of the primary site. In order to ensure that both sites might receive treatment, it is necessary to discover the primary. Another possibility is that a single tumor cell can travel through the lymph trunks or blood capillaries from an organ or the tissues of a faraway region in the body. For instance, some forms of metastatic neoplasms in the brain originate from a primary bladder tumor.
A metastatic neoplasm, when it establishes itself in a secondary site, develops its own blood networks to gather nourishment from adjoining tissues and capillaries. Tumor cells that migrate through blood capillaries branch back to those blood capillaries or penetrate blood vessel membranes nearby to raid nourishment from the blood to grow. As the neoplasm invades nearby blood vessels, it can deposit its own metastatic tumor cells in the bloodstream to migrate elsewhere.
Metastatic tumor cells that survive the killer macrophages and white blood cells that constantly scan the bloodstream for diseased microorganisms often show a tendency to migrate from certain organ areas to other specific organ areas. Medical researchers, pathologists, and oncologists have recorded certain patterns in the behavior of these migrations that can help in locating primary sites. Research on these topics is ongoing. Sometimes the presence of indicators like these in metastatic neoplasms can point to specific organs to receive imaging tests for the location of the primary sites.