Metastasis, or metastatic disease (sometimes abbreviated mets), is the spread of a disease from one
organ or part to another non-adjacent organ or part. It was previously thought that only malignant
tumor cells and infections have the capacity to metastasize
Cancer occurs after a single cell in a tissue is progressively genetically damaged to produce a cancer
stem cell possessing a malignant phenotype. These cancer stem cells are able to undergo uncontrolled
abnormal mitosis, which serves to increase the total number of cancer cells at that location. When the
area of cancer cells at the originating site becomes clinically detectable, it is called primary tumor.
Some cancer cells also acquire the ability to penetrate and infiltrate surrounding normal tissues in
the local area, forming a new tumor. The newly formed "daughter" tumor in the adjacent site within the
tissue is called a local metastasis.
TThe symptoms of metastasis varies with location of the tumors.
Initially, nearby lymph nodes are struck early. Lungs, bones, liver, and brain are the most common
metastasis locations from solid tumors.
In lymph nodes, a common symptom is lymphadenopathy
Lungs: cough, hemoptysis and dyspnea (shortness of breath)
Liver: hepatomegaly (enlarged liver) and jaundice
Bones: bone pain, fracture of affected bones
Brain: neurological symptoms such as headaches, seizures, and vertigo.