Designation given to the formation of a new neoplastic lesion, from a tumor originating from another organ. The tumor cells of the initial tumor (primary tumor) detach themselves and reach another part of the organism through the lymphatic circulation or the blood stream. At this other site, the cancer cells attach and develop, forming the metastasis. Lymph node metastases are called lymph node metastases. Metastases to other organs are generally called distant metastases. Major organs that can host metastases include:
So, when a tumor is diagnosed, many times tests are performed to find out the presence or not of metastases in these organs. This procedure is known as staging. There is a special situation in oncology in which metastases are detected without finding their origin (primary tumor). This situation is usually referred to as “metastases of unknown primary”.